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General Forums => The Mess Hall => Topic started by: Jeffy on March 14, 2007, 11:59:20 AM

Title: Gas Mileage Thread
Post by: Jeffy on March 14, 2007, 11:59:20 AM
This is the official gas mileage thread.  So, post your mileage.  Here are some stipulations though.  Please post in the thread this additional information.

Title: Re: Official Gas Mileage Thread
Post by: 4X4DAVE on March 14, 2007, 12:32:18 PM
I average 13.76 mpg, this is taking ineffect of the tire change. I have an excel spreedsheet keeping track for the past year.

I drive mostly short distances within 5 miles, so thats why mpg is low mostly because of my gears, I need to change them.

3 speed auto
1995 2.5L
33/12.5/15
3.73
Speedometer Not Calibrated
4.0 t/b, t/b spacer, and K&N cone filter

Before on 30 inch tires and 4.0 t/b and spacer, I was getting an average of 17.1 mpg and also I think that I was driving mostly highway at that time
Title: Re: Official Gas Mileage Thread
Post by: jcsanders79 on March 14, 2007, 01:33:41 PM
Getting about 12-13 on my TJ. Got a 2.5L with the 3 speed auto,  4.88 gears, 33" tires, performance chip, header, 4.0 throtle body w/ spacer, K&N cold air intake, speedo calibrated
Title: Re: Official Gas Mileage Thread
Post by: SKI BOY on March 14, 2007, 02:02:29 PM
18 mpg; 2.5L, at, 31x10.5, 3.73 gear, no speedo recal, 4.0L tb, tbs, hi-flow intake, jet chip, flowmaster exhaust, elect. rad. fan  :nod:
Title: Re: Official Gas Mileage Thread
Post by: Mozman68 on March 14, 2007, 02:30:22 PM
usually about 17 mpg....manual 2.5L running 31's...no revised speedo but checked with GPS...4.10 gearing...no engine mods.

Title: Re: Official Gas Mileage Thread
Post by: chardrc on March 14, 2007, 05:36:06 PM
13mpg

ax5, 4.10 gears, 31's.. speedo not regeared, 2.5l tbi.. no engine mods and leaks oil
Title: Re: Official Gas Mileage Thread
Post by: wrangler387 on March 14, 2007, 05:55:21 PM
This is for my 1995 2.5L with 115000 miles. I get about 20mpg, unless i go on the highway... but i dont ever do that, all city driving.

Title: Re: Official Gas Mileage Thread
Post by: lanulos89 on March 14, 2007, 05:55:37 PM
12ish mpg 2.5 of course 3 spd auto 3.73's soon to be 4.11's full performance exhaust (header to tail pipe) 4.0 throttle body, and cool air intake.  31's and speedo not yet recalibrated
Title: Re: Official Gas Mileage Thread
Post by: Elyod on March 14, 2007, 07:31:36 PM
98' 5 spd 2.5L 4.10 gears 30" no speedo calibration.  Have gps though around 17mpg, mostly around town. 
Title: Re: Official Gas Mileage Thread
Post by: Jesse-James on March 15, 2007, 12:56:21 AM
~14mpg

2.5 auto, 3.73, 31's, orig speedo gear, 4.0TB and spacer
Title: Re: Official Gas Mileage Thread
Post by: Sidscan on March 15, 2007, 12:09:24 PM


Transmision Type - Automatic - 30RHEngine Type (ie., F134, L134, Pontiac 151, AMC 150   AMC 2.5L 
Tire Size - 31x10.5
Differential Gearing - 3.73:1 stock auto
Speedometer Calibration  - No
List of ENGINE Mods if any - Bolt on 4.0 tb and tbs, PD firepower kits, champion truck 4412 plugs.
back to stock airbox.

Mostly city/hwy - little freeway.  Average mileage is 15-16. 
Title: Re: Official Gas Mileage Thread
Post by: jwrape on March 15, 2007, 01:55:18 PM
Average of 12-14 mpg.
92 YJ
2.5L
4.0TB
Electric Fan
33x12.50 on 15x10 rockkrawlers
5 speed (AX15 upgraded)
4:10 gears
Cold Air intake
Exhaust leak that actually helps performance. :lol:
Title: Re: Official Gas Mileage Thread
Post by: lanulos89 on March 15, 2007, 03:45:16 PM
who is getting beter than 21??????
Title: Re: Official Gas Mileage Thread
Post by: jcsanders79 on March 15, 2007, 05:00:48 PM
It must be the gas fairy?  I think someones math is not right :twofingers: I'm just pissed its not me!!!
Title: Re: Official Gas Mileage Thread
Post by: dunklervogel on March 15, 2007, 07:44:10 PM
14-15 mpg mostly city

Title: Re: Official Gas Mileage Thread
Post by: cromwell on March 16, 2007, 06:06:13 AM
around 8 MPG,
Tranny - AX-5
Engine - 2.5
Tires - 31"x10.5"x15 STTs
Gearing - 4.10s
Speedometer Calibration - No
Engine Mods - None

Tony
Title: Re: Official Gas Mileage Thread
Post by: Elyod on March 16, 2007, 10:08:39 AM
8mpg?!! Ouch. 
Title: Re: Official Gas Mileage Thread
Post by: lanulos89 on March 16, 2007, 10:29:00 AM
how are you getting 8 with a 5 spd 4.10's and 31's .

im getting like 12 with 3spd auto 3.73's and 31's  sry buddy impossible, unless engine mods help that much which i doubt, but if they do GET TO WORK
Title: Re: Official Gas Mileage Thread
Post by: Sidscan on March 16, 2007, 10:29:19 AM
around 8 MPG,
Tranny - AX-5
Engine - 2.5
Tires - 31"x10.5"x15 STTs
Gearing - 4.10s
Speedometer Calibration - No
Engine Mods - None

Tony

Tony,

What's your style of driving?  Is wheeling included in your 8 mpg's.  
Title: Re: Official Gas Mileage Thread
Post by: jwrape on March 16, 2007, 11:39:17 AM
who is getting beter than 21??????


I wanna say YJmechanic was getting close to 20mpg after his build up .

Maybe he will chime in.
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on March 16, 2007, 12:23:44 PM
Well, in one of my Jeeps incarnations, I was getting around 23-25mpg with all highway driving.  This was a while back when the speed limits were 55mph.  I was running 32's and stock gearing.   The Jeep was only lifted 3" back then too. :lol:

Currently, I'm getting anywhere from 16-18mpg normally.  Although with this last tank, I've had plenty of springs to 4000 rpm so I think I'm around 15-16mph this time.  It's hard to tell since my gas gauge is a bit inaccurate so I have to wait till get to the pump to know how much gas I used.

Title: Re: Official Gas Mileage Thread
Post by: chardrc on March 16, 2007, 05:03:23 PM
wow 8mpg.. that hurts my jeep gets 12-13 and its in need of a tune up and i pretty much have it floored the whole time im driving it.

wait you are in Ireland or some thing like that aren't you???.. maybe they put something in there gas that kills millage...
Title: Re: Official Gas Mileage Thread
Post by: 95 Lowbuck on March 17, 2007, 07:22:59 AM
1995  Rio Grande with a hard top.
2.5, 5speed, 4:10 gears, 4" lift, SYE, 33-10.50 BFG MT on stock wheels.
I'm getting about 16 mpg combined city and highway.
Note: Once I got my D.S. angle perfect I picked up about 2 mpg.
Title: Re: Official Gas Mileage Thread
Post by: RoKnAzn on March 19, 2007, 02:39:32 PM
This is for my 2000 2.5L with 65000 miles. I get about 12-14mpg.

Transmision Type: 3 Speed Auto
Engine Type: 2.5L 150CI
Tire Size: 37x12.5XR15
Differential Gearing: 4.88
Speedometer Calibration: Yes
List of ENGINE Mods; K&N Drop-In Air Filter, TBS, Accel 8.8 Wires, No Cat with a Turbo Tube...
Title: Re: Official Gas Mileage Thread
Post by: cromwell on March 19, 2007, 03:23:26 PM
If I knew why I am only getting 8 MPG I would fix it.  As for my driving style it is a Jeep not a sports car so I do not drive it past the posted speed of 63 MPH (100 KPH).  Lets see what have I done to try to figure it out.  First the Jeep throws a code 51 and I have replace both o2 sensors, plugs, wires, cap, rotor, pulled the throttle body and cleaned it.  And that will erase the code for about 2 hours and it is back.  The plugs do come out black.  The Jeep came with split fire plugs and I just ordered Champion Truck plugs to replace them with and they have been in for less that 15K miles. 

If anyone has suggestions for trouble shooting let me know.

Tony
Title: Re: Official Gas Mileage Thread
Post by: Justin Sinclair on March 24, 2007, 11:00:20 AM
1998 81,500 miles 20mpg mostly but have had 24

Transmision Type: 5spd Manual
Engine Type: 2.5L
Tire Size: 31x10.5XR15
Differential Gearing: Stock 4.10's?
Speedometer Calibration: Not yet
List of ENGINE Mods; K&N Drop-In Air Filter
 
 
Title: Re: Official Gas Mileage Thread
Post by: Dan Marino on March 27, 2007, 07:05:10 AM
I've got a stock 1994 YJ.  4 cylinder 2.5 MPFI engine, AX-5 manual transmission.  Original 15 inch steel wheels.  No lift of suspension mods.  Gas mileage appears to be slightly better with the hard top in place.  I get right around 22 mpg in mixed suburban driving.
Title: Re: Official Gas Mileage Thread
Post by: j33p3r on March 31, 2007, 10:09:08 PM
Average 13mpg

1998 2.5
AX-5
4.10
2" BB
33x13.50-16 on 16x8 Hellcats
No cal
No engine mods
Title: Re: Official Gas Mileage Thread
Post by: Rokcrwln on April 01, 2007, 06:01:57 PM
 16 mpg

 AMC 2.5L TBI
 AX-5
 35 X 12.50 R15 BFG M/Ts
 5.29 gears
 MSD ignition
 K&N Filter
 Indexed plugs
 
Title: Re: Official Gas Mileage Thread
Post by: aw12345 on April 01, 2007, 10:31:20 PM
an average of 20-21 mpg on mixed city highway driving. It seems to use very little fuel when 4 wheeling. On the highway it gets pretty good milage cruising 70-75

It is a 2006 SE wrangler with 2.4l engine
                                     nsg370 6 speed manual
                                     3.73 gears
                                     BFG all terain KO's 31x10.5
                                     Speedo corrected
                                     Dana 44 with diskbrakes in rear
                                     4" lift
                                     SYE kit and CV driveshaft


Art
Title: Re: Official Gas Mileage Thread
Post by: the idiot magnet on April 05, 2007, 11:06:05 AM
Just filled up this morning and did my calculations. I'm just a bit over 18MPG with a 2.5L 5 spd 4.10's 31" M/Ts, 1" body lift, hard top, and lots of added extra steel. Mileage is highway and city combined for a daily driver.
Depending on my driving habits I average 17 to 19 and that's important to know since the gas guage always reads full. Need to fix that.
Title: Re: Official Gas Mileage Thread
Post by: Erik on April 08, 2007, 01:15:38 PM
Title: Re: Official Gas Mileage Thread
Post by: aw12345 on April 08, 2007, 01:33:22 PM
darn at 10 mpg you can drive a crewcab dually my old carburated f350 dually would get 13.5 on the highway and about 8-9 in the city. You might want to do something about that uits a lot of gas for a little 4 banger

Art
Title: Re: Official Gas Mileage Thread
Post by: jung4g on April 11, 2007, 04:09:19 PM
I get around 13 I think...

That's with Hardtop and full doors on (winter mode).

Running 32 x 11.50s
4.10 gearing
2.5 MPI
AX5
K&N with cut box
Electric Fan
4.0 TB
Dynomax Catback w/ Hi-Flow Cat

Title: Re: Official Gas Mileage Thread
Post by: 6099 on April 23, 2007, 11:55:26 PM
18.5MPG

Transmision Type **AX5

Engine Type **2.5 MPFI

Tire Size **34"

Differential Gearing **7.1

Speedometer Calibration **GPS calculated

List of ENGINE Mods if any **4.0TB, no CAT, K&N in stock airbox. Header, stock.
Title: Re: Official Gas Mileage Thread
Post by: Mozman68 on April 24, 2007, 02:58:46 PM


Differential Gearing **7.1




Wha wha whaaaaaa???? :puzzled:
Title: Re: Official Gas Mileage Thread
Post by: chrisfranklin on April 24, 2007, 04:32:58 PM
This is the official gas mileage thread.  So, post your mileage.  Here are some stipulations though.  Please post in the thread this additional information.
About 16mpg city, 18-19mpg highway.  Used to run 20mpg highway on 205s

Transmision Type: AX-5
Engine Type: AMC 2.5L MPFI
Tire Size:  235/75/15,  roughly 29s
Differential Gearing: 4.10
Speedometer Calibration: No (Checked vs. GPS and it seemed right on the money)
List of ENGINE Mods if any: Borla exhaust, Full PD Ignition, Autolite Iridium plugs, Mobil 1, 62mm TB, TB spacer, air box restrictions pulled. 
Weight: Have 20 gallon gas tank mod which probably ads only 30lbs to vehicle weight on a full tank; no other significant weight additions such as winch, bumpers, racks, armor, larger axles, etc.
 
 
 
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on April 24, 2007, 04:57:05 PM


Differential Gearing **7.1




Wha wha whaaaaaa???? :puzzled:

He's running Volvo axles 7:1 is correct.
Title: Re: Official Gas Mileage Thread
Post by: Mozman68 on April 24, 2007, 09:15:11 PM


Differential Gearing **7.1




Wha wha whaaaaaa???? :puzzled:

He's running Volvo axles 7:1 is correct.


aaahhhhh...Mr. South America......we need more pics....
Title: Re: Official Gas Mileage Thread
Post by: Liljeepz on April 29, 2007, 04:59:50 PM
16 MPG here

2.4L
31x10" tires
4.11 gears
speed-o gear is not changed yet.
Title: Re: Official Gas Mileage Thread
Post by: Elyod on April 29, 2007, 10:22:10 PM
I just replaced my paper air cleaner with a drop in K&N for the 4.0 litre and my mileage went up to 22.5 from 17. My older one was a little dirty but almost 6 mpg is nuts!  Definitely worth the 60 bucks.
Title: Re: Official Gas Mileage Thread
Post by: Sidscan on May 02, 2007, 02:10:58 PM
I just replaced my paper air cleaner with a drop in K&N for the 4.0 litre and my mileage went up to 22.5 from 17. My older one was a little dirty but almost 6 mpg is nuts!  Definitely worth the 60 bucks.

Wow that's quite a change.  My best mileage is 17 and everything seems pretty well tuned.  What other secrets do you have?  I'm thinking you must drive down hill both ways.  ;)  I would be interested to hear your average MPG over a 6 month span.  You continue to get the 22 pretty consistantly, then I'm all in.  Thanks for postin  :smokes:
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on May 02, 2007, 04:59:50 PM
I just replaced my paper air cleaner with a drop in K&N for the 4.0 litre and my mileage went up to 22.5 from 17. My older one was a little dirty but almost 6 mpg is nuts!  Definitely worth the 60 bucks.

Wow that's quite a change.  My best mileage is 17 and everything seems pretty well tuned.  What other secrets do you have?  I'm thinking you must drive down hill both ways.  ;)  I would be interested to hear your average MPG over a 6 month span.  You continue to get the 22 pretty consistantly, then I'm all in.  Thanks for postin  :smokes:

Well, you can't really say the K&N did anything since he never tried a clean paper element first.  If any filter is really dirty it will reduce power.  Was the filter worth $60, maybe maybe not. :whistle:
Title: Re: Official Gas Mileage Thread
Post by: Elyod on May 02, 2007, 06:01:40 PM
I have had the paper filter in there for a year, when i got it, it was new (I hope) and i still only got around 18~19 mpg.  I have owned my jeep for four years now and have never seen as good gas mileage as i am now.  My two cents:  the K&N is worth it, not to mention it is cleanable and reusable. 
Title: Re: Official Gas Mileage Thread
Post by: Bounty Hunter on May 07, 2007, 12:26:53 PM
18mpg (gps verified) with:
bias 36" TSL's
5.38 gears
AX5
Mopar stage 2 cam
Airtube and conical K&N
4.0L TB and spacer
electric fan
Firepower iginition system

Nice being able to accelerate uphill in 4th and 5th gears, correct axle gearing makes all the difference in the world.

I've gotten 21+ with 4.10 gears back when I was running 31" and 32" tires.
Title: Re: Official Gas Mileage Thread
Post by: sharpxmen on May 13, 2007, 11:07:05 PM
13 or 14 mpg (never better) city and/or highway (with all she's got - top speed is 85mph with favorable wind conditions :'(). Rarely use 5th gear (only downhill otherwise it slows down...)

95 YJ / 2.5L MPFI
 - transmission: stock AX-5, stock diffs (4.10 if i'm not mistaking), stock t-case
 - tires: 33x12.50x15 BFG M/T
 - 3'' lift + 1'' body
 - cold air, 4.0TB, spacer, high ouput alternator
 - no speedo calibration but measurements based on gps

Title: Re: Official Gas Mileage Thread
Post by: kidwithayj on May 23, 2007, 11:39:18 AM
NV3550
2.5L
30X9.5 BFG AT
4.10
Speedometer Calibration [No]
4.0L Throttle Body, Rock-It intake, new exhaust

My mileage is not really consistent. I have 104,500 miles on the Jeep. When I first got it, it averaged about 17.5mpg no matter how I drove. Now that it's a bit older, my mileage can go anywhere from 13mpg to the highest ever of 19.7mpg (just a few weeks ago, actually). I would say my average is around 16mpg. I think the motor is losing compression, so that could account to less mileage.
Title: Re: Official Gas Mileage Thread
Post by: 01amberfirewv on June 18, 2007, 02:47:39 PM
01 TJ AX5 Stock 4.11's and 31" TrXus Mt's

*OK but what's your mileage?
Title: Re: Official Gas Mileage Thread
Post by: InFlames on June 20, 2007, 02:18:47 PM
17mpg average city/highway mix


Transmision Type: AX-5 manual
Engine Type: AMC 2.5L
Tire Size: 33x12.5x15(Truxus M/T= heavy)
Differential Gearing 4.88
Speedometer Calibration: yes
List of ENGINE Mods if any: None
Notes: Run all synthetic fluids,aftermarket muffler added,run alloy rims
    Also live in ozark mountain area so constantly deal with hills.
Title: Re: Official Gas Mileage Thread
Post by: larryp on June 23, 2007, 11:08:42 PM
 About 18mpg since I lifted it and added larger tires.

tranny; AX-5 manual
engine; 2.5 liter tbi
 tires; 31x11.5x15 LT Wildcat AS
gears; 4.10
speedo cal.; no
mods; 2 1/2" low pressure exhaust and cat.

 As of today engine has 126,000 miles and uses no oil. Most of the miles are at highway speed as I live 16 miles from town and work.

Title: Re: Official Gas Mileage Thread
Post by: Jeffy on June 29, 2007, 11:38:54 PM
Well, here's an update. I joined the 14-15mpg club.  I've run it this way for a few months to make sure it wasn't a fluke.  So tonight I swapped some stuff back and I'll be doing some more testing.  I have to say though, dropping form 16-18 mpg to 13-15 mpg makes a big difference for day to day driving.  I don't want to jump to conclusions so I'm holding off disclosing what is happening until I see if my mileage bounces back.
Title: Re: Official Gas Mileage Thread
Post by: jfrabat on July 16, 2007, 04:19:12 PM
On my 94 YJ 2.5L with bout 117K miles, I get about 15 mpg (but my speedo was not calibrated; I just replaced it, but have not yet filled the tank up), mostly doing short drives combining both highway and city (it's about 10 miles to work).

Transmision Type: AX-5
Engine Type; AMC 2.5L MPFI
Tire Size: 31x10.5r15 BFG h/t
Differential Gearing: 4.10
Speedometer Calibration: No
Engine Mods: TB Spacer, Bosch injectors (Mustang), K&N Air Filter in stock box (restrictors removed), aluminum radiator with Ford Taurus fan with DC Control speed controller (and override ON and OFF switch, but mostly stays on Auto), Accel 42K Volts coil, no leaks.

Felipe
Title: Re: Official Gas Mileage Thread
Post by: spoonman on July 26, 2007, 02:01:02 PM
i've put 3 tanks thru the jeep since tune up. crappy plugs ( and everything else) got 16 with no top. since the tune up, fuel system cleaner got 19 mpg around town and no top. it's a 97 stocker with 111000 on it.  is this good? i'll prolly drop a k&n 4.0 tbi and spacer next
Title: Re: Official Gas Mileage Thread
Post by: dexetr30 on July 31, 2007, 05:14:37 PM
16-19. Since swapping out the plugs/cap & rotor and adding the jet chip it's closer to 19. :thumbsup: I still think I can do better. Maybe some sea foam and some injector cleaner.
 Prior to these mods I was just above 11 mpg. :'(
Title: Re: Official Gas Mileage Thread
Post by: lanulos89 on August 23, 2007, 03:11:28 PM
im back from the dead with an update.  so i had my jeep in the air and noticed that the axle shafts never unlock from the driveshaft so its been spining constantly for god know how long since december when i swaped my axles out.  i hammered the fork back out of 4wd nd i get like 15 mpg now its amzing  :dance:
Title: Re: Official Gas Mileage Thread
Post by: jfrabat on August 30, 2007, 04:17:36 PM
On my 94 YJ 2.5L with bout 117K miles, I get about 15 mpg (but my speedo was not calibrated; I just replaced it, but have not yet filled the tank up), mostly doing short drives combining both highway and city (it's about 10 miles to work).

Transmision Type: AX-5
Engine Type; AMC 2.5L MPFI
Tire Size: 31x10.5r15 BFG h/t
Differential Gearing: 4.10
Speedometer Calibration: No
Engine Mods: TB Spacer, Bosch injectors (Mustang), K&N Air Filter in stock box (restrictors removed), aluminum radiator with Ford Taurus fan with DC Control speed controller (and override ON and OFF switch, but mostly stays on Auto), Accel 42K Volts coil, no leaks.

Felipe


The new speedo has not done anything for gas mileage; it still is 15 mpg.  I do like knowing what speed I am driving at, though!
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on August 30, 2007, 04:23:27 PM

The new speedo has not done anything for gas mileage; it still is 15 mpg.  I do like knowing what speed I am driving at, though!

Since you have only 31's the difference is probably around 3% difference.  You should still see the mileage creep up a little with the calibrated speedometer/odometer.
Title: Re: Official Gas Mileage Thread
Post by: jfrabat on August 31, 2007, 09:02:36 AM
Since you have only 31's the difference is probably around 3% difference.  You should still see the mileage creep up a little with the calibrated speedometer/odometer.

The difference in the speed before the calibration was bout 5~6 mph at 65 mph, so it was enough to get me a ticket if I was not careful.  As for the mpg, it improved, but only by about 0.05~0.1 mpg (that's more than the margin of error I figure I have, so I dont consider it).

I figure once I get around to it and take my engine apart and clean everything up nice it will improve significantly...  But that may be some years away, as this is still my daily driver, and if I take it apart, I dont have a mode of transportation!

Felipe
Title: Re: Official Gas Mileage Thread
Post by: jeepheap on September 02, 2007, 06:34:31 PM
ok ay finally got around to doing the math one this one....
90 yj 2.5, ax5 (with no fifth gear) ,stock diffs (4.10) stock intake, cherry bomb muffler but other wise stock exhast, 4" lift 33" tires.... and mind you this is while i was towing my time out camper, about 350lbs fully loaded....
i was getting 19.5 mpg!!! i am so happy. got figure it out with my next check (to be able to get a full tank) and my gps with out the trailer. :beer:
Title: Re: Official Gas Mileage Thread
Post by: chardrc on September 03, 2007, 07:28:14 AM
are you kidding me i couldn't get that rolling downhill with my 2 inch lift an 31's.
Title: Re: Official Gas Mileage Thread
Post by: jeepheap on September 03, 2007, 07:37:54 AM
yeah... i'm serious. i checked it going out to bath ny and double checked on my way from bath to lake george. i thought it was incredible myself, that's why i did the math twice.

i didnt have 5th but it's not like i would have used it anyways, with all the weight. i even had to downshift to third most of the time on hills. i was following my brother in law in the minivan (maybe i was drafting?..) and he had it set at 60 the whole way. can't wait to see what i'm getting with out the trailer.
Title: Re: Official Gas Mileage Thread
Post by: SDWE61988 on September 05, 2007, 08:41:20 AM
I just read through this thread and I guess I am doing pretty good with my jeep.  I got her almost three years ago, and was averaging 13-15 mpg.  I have done everything I can think of and now I am averaging 17-19 mpg.  The Jeep has 206500 miles on her.  I have a 95 2.5l MPFI with 5 spd, 31 inch tires with a stock rear end.  I changed the speedo gear last year after I got a speeding ticket, believe it or not :roflol: (Ironically I was trying to build up a enough speed to make it up the next hill!).  I also Added the trottle body spacer, cleaned the injectors, used seafoam, tune up (twice), and a couple of air filters.
I can maintian @ 65-70 mph in the highway (flat areas) and still achieve this, along with easy starts.  I start hard or run anything over 70, the mileage drops like a rock.
Title: Re: Official Gas Mileage Thread
Post by: chardrc on September 05, 2007, 02:43:29 PM
i didn't have 5th but it's not like i would have used it anyways, with all the weight. i even had to downshift to third most of the time on hills. i was following my brother in law in the minivan (maybe i was drafting?..) and he had it set at 60 the whole way. can't wait to see what i'm getting with out the trailer.

a drafting helps allot with my jeep. there i a hilly highway be me and if i have a person to draft with i can go 60- but if i loose my draft Im struggling to keep 45 on the hills. and these hills aren't all that step just last forever.
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on September 05, 2007, 03:11:42 PM
yeah... i'm serious. i checked it going out to bath ny and double checked on my way from bath to lake george. i thought it was incredible myself, that's why i did the math twice.

i didnt have 5th but it's not like i would have used it anyways, with all the weight. i even had to downshift to third most of the time on hills. i was following my brother in law in the minivan (maybe i was drafting?..) and he had it set at 60 the whole way. can't wait to see what i'm getting with out the trailer.

I think the reason was that you were going 60mph.  When you start pushing it to 65 and higher your gas mileage will tank.  Also, were there many hills?  What's the weight of the trailer?  Drafting probably also helped.  I used to draft big rigs.  You don't have to get really close to them to get into the draft.  You can actually hear it get quieter.  It's usually around a car length behind the trailer.
Title: Re: Official Gas Mileage Thread
Post by: jeepheap on September 05, 2007, 05:05:11 PM
yeah there were hills. anybody been up 81? it's alot of hills. and the trailer weighed in at about 350.
Title: Re: Official Gas Mileage Thread
Post by: jfrabat on September 07, 2007, 12:55:40 PM
I think the reason was that you were going 60mph.  When you start pushing it to 65 and higher your gas mileage will tank.  Also, were there many hills?  What's the weight of the trailer?  Drafting probably also helped.  I used to draft big rigs.  You don't have to get really close to them to get into the draft.  You can actually hear it get quieter.  It's usually around a car length behind the trailer.

I agree with this; I tested this when i went to the Florida Keys last weekend, and I just drifted behind the RV's heading down and back up, and not only was my engine workload SIGNIFICANTLY lowered, but the gas mileage increased significantly.  By the way, I also shut down the e-fan during the highway run...  Which means I almost overheated when I got to the Keys because I forgot to turn it back to auto, but that's a WHOLE OTHER STORY!   :biggrin:

Felipe
Title: Re: Official Gas Mileage Thread
Post by: dexetr30 on September 16, 2007, 06:17:40 PM
yeah there were hills. anybody been up 81? it's alot of hills. and the trailer weighed in at about 350.

I live in northeast PA and I travel 81 heavily. I have never gotten that kind of mileage. I'm only running 235's with no lift currently and I'm lucky to get 15 mph. When we were in Maryland/Delaware a few weeks ago where it's flat we were getting around 19 mpg.
Title: Re: Official Gas Mileage Thread
Post by: st.chevrolet on October 04, 2007, 09:50:12 PM
I have a 94 YJ 2.5L, 5 speed, 4.10s, and 235/75 R 15 that when I 1st bought it got about 17-18 mpg in town, it was bone stock other than a little bit of a bigger tire. The few upgrade/tune-ups I have done so far have brought my mileage up to 21+ mpg in town.
The upgrades/tune ups include:
New NGK plugs
New fuel filter
MSD 8.5mm Super Conductor Spark Plug Wires
Home made intake with K&N filter
Electric two speed cooling fan
4.0L throttle body
Molyslip Oil Supplement (molybdenum disulfide oil additive)
  With these few mods I have gotten as high as 24mpg but most of the time it gets about 21mpg.

 I am in the process of turbo charging my 2.5L, and from what I have read after turbo charging I should see increases of somewhere between 4-5 mpg. This information comes from others who have done the same procedure to there 2.5L. Needles to say a gain of 4-5 mpg is great but while also making the same or better HP power & torque of the 4.0L   :dance:

Title: Re: Official Gas Mileage Thread
Post by: swatsniper1s1k on November 08, 2007, 05:16:04 PM
91 YJ, 2.5L. 5spd, 4.10s street tires dimension of am. racing wheel is 15x10 tires are street prolly 27 or 28 inches. Only engine upgrades are new spark plugs, 8.5mm super conductors, high voltage coil, new distributer cap, and Flowmaster series 40 muffler. with that all, i'm pushing 26 miles a gallon highway, cruisin about 5mph under speed limit cuz my squirrels cant run fast enough, and some extreme hills. I am trying to decide whether to drop the money into a turbo, supercharger, or inline 6. trying to get the most power possible without jeopardizing vehicle balance with a chevy small block 305. anybody have any knowledge as to what works best?
Title: Re: Official Gas Mileage Thread
Post by: brian674 on November 19, 2007, 04:34:42 AM
OK, I got 22 MPG and 23 MPG, all highway with an average speed of 70 MPH. This was 3 weeks ago.

I get about 18 MPG in my normal everyday driving, which is mix of town and highway everyday.

2003 TJ SE
I have a stock 2.4L
I think it is a NVG3550 tranny, but not sure
(http://i208.photobucket.com/albums/bb33/brian674/IMG_0142.jpg)
A NP231/NVG231 T-case
D30/D35 axles with 4:10 gears.
Title: Re: Official Gas Mileage Thread
Post by: brian674 on November 19, 2007, 05:09:21 AM
Forgot to specify tire size (215-75-R15 Goodyear Wranglers)
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on November 21, 2007, 01:39:05 PM
I think it is a NVG3550 tranny, but not sure

If it's stock it has an NV1500.
Title: Re: Official Gas Mileage Thread
Post by: jrollings on March 09, 2008, 06:27:54 PM
94' yj
2.5l
130,000
15 mpg
4" suspension lift
33" mud rovers
3.73 stock gears: will be going to 4.56s soon as well as upgrading to super 35 kit and 4340 alloy front axles
high flow intake

needs new air filter and tune up and exhaust leak fixed  :beers:
Title: Re: Official Gas Mileage Thread
Post by: BarneyJeep on March 26, 2008, 07:59:46 AM
'98 TJ
2.5l (140k miles)
ax-5
30/35 w/ 4.10's and open
34" LTB's on 15x8 black steelies
mainly 4th gear try to keep the motor around 3k RPM
avg 15-16 MPG on 87 oct
Title: Re: Official Gas Mileage Thread
Post by: BarneyJeep on March 26, 2008, 08:01:10 AM
edit: 4.0l intake tube with open "ricer" filter
       Super Turbo muffler with stock cat + tailpipe
Title: Re: Official Gas Mileage Thread
Post by: st.chevrolet on March 29, 2008, 02:24:10 PM
'98 TJ
2.5l (140k miles)
ax-5
30/35 w/ 4.10's and open
34" LTB's on 15x8 black steelies
mainly 4th gear try to keep the motor around 3k RPM
avg 15-16 MPG on 87 oct

I was just curious as to why you would want to keep your engine at 3000 RPM, at that RPM your jeep would use more fuel. 
Title: Re: Official Gas Mileage Thread
Post by: Mr_Random on March 30, 2008, 01:28:51 AM
I was just curious as to why you would want to keep your engine at 3000 RPM, at that RPM your jeep would use more fuel. 

Yes, but with the highest torque. The 4cyl usually peaks around 3000RPM in torque, and is therefore most efficient in the comparison between incoming fuel/air and output torque. If I drive 25mph, with the engine in 4th gear, and around 1700 RPM, I get worse gas mileage than running in 3rd gear, at 2600 RPM or so. (just as an example, I don't exactly remember which RPM goes where, as I HATE driving 25 and do it as little as possible).

Actually, because of the nixed cat on mine (PO did it, not me), my whole curve moved up (but gained an HP or two) and it's most efficient for me to run going way too fast for my driving brick, with the RPMs up even higher than most 4cyls.

When cruising fast, 35-4000 RPM is the best for me, I stay in fourth going up to ~75mph, until either my vibrating foot or my sense of well-being makes me shift to fifth (and this is with 215/75r 15's!, wait until I get some 30's or 31's!).
Title: Re: Official Gas Mileage Thread
Post by: Mr_Random on March 30, 2008, 01:31:47 AM
Appearantly no edit allowed... 14mpg all-around town (stupid high idle EATS GAS), 20mpg mixed/county driving, ~25 highway (haven't done this for a while though, will do again soon).
Title: Re: Official Gas Mileage Thread
Post by: howler on March 30, 2008, 07:04:39 AM

2006 TJ
Avg. 18.5 mpg
I usually drive short trips

2.4 L
3.73:1
6 speed manual
31 inch MTR's

No real mods yet, hoping you guys can help with that.
Title: Re: Official Gas Mileage Thread
Post by: Rob the plumber on March 30, 2008, 12:23:19 PM
4000 rpm cruising down the freeway? Holy crap.......
Title: Re: Official Gas Mileage Thread
Post by: Mr_Random on March 31, 2008, 01:52:48 AM
4000 rpm cruising down the freeway? Holy crap.......

holy crap as in high? Yeah, that's when my speedo (stops at 85) is bouncing around past it's top end, I've only done it two or three times though... and when my XJ was stock height... I'll probably never try it again...

With taller tires my RPM's should drop, but I'll probably never go the same speed, so I'll be happy.
Title: Re: Official Gas Mileage Thread
Post by: BarneyJeep on April 03, 2008, 07:06:44 PM
update: 170mile trip this weekend... cruise set @ 66mph (according to GPS), in fourth gear @ 2850 RPM... 16.1MPG no drafting
Title: Re: Official Gas Mileage Thread
Post by: Bounty Hunter on April 16, 2008, 02:14:31 PM
I agree with keeping the 2.5 at 3000rpm's, mine cruises best about there.

Keep in mind it takes the 'puter a good while to adjust to performance mods.  My mileage went way up a few weeks after installing a 62mm throttle body.  Takes a certain amount of key or warm-up cycles to relearn.
Title: Re: Official Gas Mileage Thread
Post by: jfrabat on April 16, 2008, 05:30:18 PM
With all the mods I have done and the same driving style, I've seen my mpg increase from 14.4 to 15.8; I still want to break the 16mpg barrier, though, so I will try the 3K rpm and see how that goes.
Title: Re: Official Gas Mileage Thread
Post by: mpyusko on April 27, 2008, 12:45:39 AM
1997 TJ 4cyl, 5pd, 145,000 miles.

Worst ever:  14.5 towing a ~2000 lb trailer. (Adk's)
Best ever:     19.5 towing a ~2000 lb trailer. (Rocketry gear)

Usually, puttering gives me 16.5 and highway up to 17.5.

(My TPS died once at Paragon and I drove 4.5 hours home getting 15 MPG)
Title: Re: Official Gas Mileage Thread
Post by: Rob the plumber on April 27, 2008, 03:34:43 AM
I don't know how much yet, but my mileage definitely increased after installing the turbo. it looks to be about 3 mpg or so. I guess not having to use half the throttle maintain 60 mpg helps.
Title: Re: Official Gas Mileage Thread
Post by: TrailsLessTaken on April 30, 2008, 09:26:24 AM
--------------------------------------------------------------------------------
around 8-10 MPG,
Tranny - AX-5
Engine - 2.5
Tires - 35X12.5X15 Wranglet mtr
Gearing - 4.10s
Speedometer Calibration - No
Engine Mods - air intake, flowmaster exhaust,
120,000 miles and the mileage doesnt change much no matter if its city or highway, but i think the motor may be about shot
Title: Re: Official Gas Mileage Thread
Post by: Rob the plumber on May 01, 2008, 06:09:07 PM
--------------------------------------------------------------------------------
around 8-10 MPG,
Tranny - AX-5
Engine - 2.5
Tires - 35X12.5X15 Wranglet mtr
Gearing - 4.10s
Speedometer Calibration - No
Engine Mods - air intake, flowmaster exhaust,
120,000 miles and the mileage doesnt change much no matter if its city or highway, but i think the motor may be about shot

There is something wrong there. You should be around 15 mpg.
Title: Re: Official Gas Mileage Thread
Post by: TrailsLessTaken on May 01, 2008, 08:12:17 PM
when i got the jeep about 5 or 6 years ago it used to be alot be alot better but just the last year or two its started getting worse and i bought a new truck and just put it on the back burner but now i have the money to finally get the engine rebuilt that way i can finally get back out on the trail
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on May 02, 2008, 05:10:12 PM
Bad O2 sensor?
Title: Re: Official Gas Mileage Thread
Post by: TrailsLessTaken on May 02, 2008, 08:44:12 PM
it could be but im not gettin a check engine light coming on and when i hook the computer up to it, i dont get any codes to pop up on it. i'll go buy a new one this weekend and see what that does
Title: Re: Official Gas Mileage Thread
Post by: somthinwicked on May 07, 2008, 12:34:35 PM
15 mpg mostly, 1998 2.5L SE. 31/10.5 tires/wheels, Engine Light On, getting it looked at asap.
Title: Re: Official Gas Mileage Thread
Post by: Mozman68 on May 08, 2008, 06:30:06 PM
13.5 with the new gears.....and new weight. Not as bad as I thought it would be, but I was hoping for 15. Tracking another tank full to see if I get the same.
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on May 08, 2008, 06:31:51 PM
13.5 with the new gears.....and new weight. Not as bad as I thought it would be, but I was hoping for 15. Tracking another tank full to see if I get the same.

I bet it's the gearing.  :wall:
Title: Re: Official Gas Mileage Thread
Post by: Tsd on May 08, 2008, 07:21:07 PM
I got 16, everything stock, fat driver and busted o2 sensor  :doggy:
Title: Re: Official Gas Mileage Thread
Post by: dexetr30 on May 09, 2008, 01:32:48 PM
I was getting around 15 mpg. A month or so I bored out the intake manifold to match the bore size of the 4.0l t.b. and installed a Taurus fan. As the weeks went on I noticed crisper throttle response and better overall power. I guess I had to let the ecm catch up with the intake mod? Anyway... I'm hitting an average of 18 mpg now. My catalytic converter is starting to smell a bit and it's time to change the o2 sensor. Things may improve after I do these two things also.
Title: Re: Official Gas Mileage Thread
Post by: Mozman68 on May 23, 2008, 08:37:29 AM
update.....14.3 and 14.7 on my next two fill-ups respectively.

And then the next one earlier this week.....15.3.  :clap:

Gonna keep tracking until I end up with a good average.
Title: Re: Official Gas Mileage Thread
Post by: bidi on May 25, 2008, 12:56:20 PM
I'm amazed how bad mileage you guys are getting.  I've always gotten 20mpg average, sometime it would hit 18mpg, but that's the lowest it's ever been.  This is with 31" and 2" lift.  I generally travel in fairly flat roads, but it's pretty windy where I live now... that accounts for the 18mpg.  I've actually been thinking of getting a DD, but not sure since I don't take the Jeep out anymore I wouldn't have a reason to keep it anymore.
Title: Re: Official Gas Mileage Thread
Post by: Mozman68 on May 25, 2008, 08:54:50 PM
I'm amazed how bad mileage you guys are getting.  I've always gotten 20mpg average, sometime it would hit 18mpg, but that's the lowest it's ever been.  This is with 31" and 2" lift.  I generally travel in fairly flat roads, but it's pretty windy where I live now... that accounts for the 18mpg.  I've actually been thinking of getting a DD, but not sure since I don't take the Jeep out anymore I wouldn't have a reason to keep it anymore.

..and this is GPS certified?? Or, you've changed your speedo gear??

I dipped back down into the 14's with my last fill up...I'll take 14.5 as a great average any day with my setup!! :thumb:
Title: Re: Official Gas Mileage Thread
Post by: bidi on May 27, 2008, 06:33:36 PM
I changed the speedogear.  It's also been calibrated since then though.  My fuel pump short circuited on the trail about a year ago (cost me $800, too... bastards) and they went ahead and calibrated everything.  Mileage increased after the new fuel pump by about 1-2 mpgs.

On that note, with the original speedo gear and larger tires you'd actually seem to get lower mpg since you're moving more than your odometer is registering (your odometer would say you traveled 100 miles instead of 110, for example, so you'd be short 10%).
Title: Re: Official Gas Mileage Thread
Post by: Mozman68 on May 28, 2008, 02:35:36 PM
On that note, with the original speedo gear and larger tires you'd actually seem to get lower mpg since you're moving more than your odometer is registering (your odometer would say you traveled 100 miles instead of 110, for example, so you'd be short 10%).

I was short when I ran the 31's....but I don't have a speedo gear anymore....I'm electronic now, so running about 10% MORE...using the GPS as a speedo for now and also to make sure I am using accurate mileage numbers.

Too cheap to spend the hundred bucks for the electronic module....can't even remember what it's called.  The guys who did the work on my rig thought I had one for some reason.
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on June 03, 2008, 05:41:05 PM
I was short when I ran the 31's....but I don't have a speedo gear anymore....I'm electronic now, so running about 10% MORE...using the GPS as a speedo for now and also to make sure I am using accurate mileage numbers.

Too cheap to spend the hundred bucks for the electronic module....can't even remember what it's called.  The guys who did the work on my rig thought I had one for some reason.

The Dealer can actually calibrate that for you.  Otherwise, you can get a Jet or Dakota or Superlift module...
Title: Re: Official Gas Mileage Thread
Post by: JamesPadgett on July 06, 2008, 10:08:19 PM
according to my uncalibrated speedo i am getting 13mpg.
Transmision Type  AX-5
Engine Type AMC 2.5L TBI
Tire Size 33/ 10.5/ 15
Differential Gearing 4.88
Speedometer Calibration n
List of ENGINE Mods: ported throttle body, throttle body spacer, k&n

I am planning a sm420 /dana300 swap so i am thinking when i do that i will fig out my speedo.
Title: Re: Official Gas Mileage Thread
Post by: aw12345 on July 07, 2008, 03:21:12 AM
went from 33/12.5 tires to goodyear mtr 32/11.5 both sets of tires are the same diameter milage for short trips went from 15 to 17 mpg am quite happy about that
Title: Re: Official Gas Mileage Thread
Post by: whitejeep94 on August 05, 2008, 02:17:24 PM
I have a 94 and run 31 with 4.10 /my upgrades are cut the airbox with k&N and knew header  and flowmaster 40 series airaid spacer and i still only get 10 mpgs

 what can i do to get my mpgs up ?
Title: Re: Official Gas Mileage Thread
Post by: jfrabat on August 16, 2008, 06:55:00 PM
I have a 94 and run 31 with 4.10 /my upgrades are cut the airbox with k&N and knew header  and flowmaster 40 series airaid spacer and i still only get 10 mpgs

 what can i do to get my mpgs up ?

Buy a Prius!   :roflol:

No, just keep your speed down at 55 mph in the highway, be gentle on the throttle when the light goes green, and coast to stops signs and red lights.  I am assuming your jeep is running smoothly and you do all the tune-ups and oil changes in a timely fashion...
Title: Re: Official Gas Mileage Thread
Post by: Bill M. on August 17, 2008, 01:20:51 PM
A prius? hahah.. Jeff Dunham....
Title: Re: Official Gas Mileage Thread
Post by: Jesse-James on August 17, 2008, 05:52:11 PM
A prius? hahah.. Jeff Dunham....

Not just a Prius, a "Blue" Prius.....  :lol:
Title: Re: Official Gas Mileage Thread
Post by: Compstall on October 22, 2008, 11:49:40 PM
I just marked my last fuel tank at 24.xx mpg based on the last fill-up.  A couple days ago I finished up my own cold-air kit.  This Jeep is mainly driven to work and back, 4 miles each way.  We'll see how the cold-air kit fares...
Title: Re: Official Gas Mileage Thread
Post by: Mozman68 on October 24, 2008, 09:45:41 AM
I've been tracking pretty steadily for 6 months now since my latest upgrades....about 14.7 mpg on average...I'm happy with that all things considered.
Title: Re: Official Gas Mileage Thread
Post by: TahoeYJ on October 31, 2008, 11:56:32 AM
92 with about 45-50K on the clock, 5 spd, 4:88 gears, 4.0 TB, ported intake, K&N w/ airbox restrictor removed, 35"  MT/R's ran at 35 PSI, Magnaflow exhaust, and I might be forgetting something. I average anywhere from 18-20 MPG depending on how I drive. With a light foot I can get at least 19 around town and if I stay at 70 or below highway, I get 19-20  :twofingers:  :naughty:
Title: Re: Official Gas Mileage Thread
Post by: FourbangerYJ on December 20, 2008, 10:47:06 AM
Tranny = AX5
Motor = 2.5L MPFI
Tire size = 37 (32psi)
Gearing = 5.38
Checked my speedo with a GPS it's on the money!
Engine mods = Rockit City intake tube with K/N. 4.0TB non bored intake. Flowmaster 50 series muffler.

My last run I checked my mileage. I got 12.9 MPG. This is doing 65-70 MPH thru some hills and flat HWY. I  :lol: real hard when one of the guys running a 4.0 XJ told me I was driving to fast and to keep it under 65MPH!

When I was running 4.88's and 35's I was getting about 10 MPG.

When I bore the intake and add the 62mm TB I will update.
Title: Re: Official Gas Mileage Thread
Post by: TahoeYJ on December 21, 2008, 11:45:58 AM
Tranny = AX5
Motor = 2.5L MPFI
Tire size = 37 (32psi)
Gearing = 5.38
Checked my speedo with a GPS it's on the money!
Engine mods = Rockit City intake tube with K/N. 4.0TB non bored intake. Flowmaster 50 series muffler.

My last run I checked my mileage. I got 12.9 MPG. This is doing 65-70 MPH thru some hills and flat HWY. I  :lol: real hard when one of the guys running a 4.0 XJ told me I was driving to fast and to keep it under 65MPH!

When I was running 4.88's and 35's I was getting about 10 MPG.

When I bore the intake and add the 62mm TB I will update.
I always have people telling me there's no need to go above 65 on the highway in a lifted Jeep. I tell them there is, because it's fun  :smokes: I love being able to jet down the highway at 75-80 passing lifted fullsize trucks and what not, half the time they decide they need to pass me right back, guess they don't expect it from a Jeep  :blbl:

Mileage goes down at those speeds, but when I want to get somewhere relatively quick I couldn't care less about the few MPG's I lose
Title: Re: Official Gas Mileage Thread
Post by: FourbangerYJ on December 21, 2008, 05:25:39 PM

Mileage goes down at those speeds, but when I want to get somewhere relatively quick I couldn't care less about the few MPG's I lose

That is exactly how I feel. If I was worried about mileage I wouldn't drive a Jeep. Besides I only put between 1-2k miles a year on it. So when I use it it's to go wheeling, and I want to get there fast. With the new gearing it's a real pleasure to drive! No more 3rd gear on the hills. :dance:
Title: Re: Official Gas Mileage Thread
Post by: TahoeYJ on December 25, 2008, 06:09:56 PM
That is exactly how I feel. If I was worried about mileage I wouldn't drive a Jeep. Besides I only put between 1-2k miles a year on it. So when I use it it's to go wheeling, and I want to get there fast. With the new gearing it's a real pleasure to drive! No more 3rd gear on the hills. :dance:
I have to use 3rd gear when I get into steeper hills at higher elevations, but that's so I can ring it out to 65-70 and maintain speed. I don't mind bringing my 4 popper up to it's limit  :biggrin:

I've made it from my house to South Lake Tahoe in juuuust over 3 hours. Mileage really went down that trip, but again I didn't care  :hump:

Anyway, enough mileage thread whoring  :pirate:
Title: Re: Official Gas Mileage Thread
Post by: 93yjFirstJeep on January 27, 2009, 06:52:10 PM
tranny: ax5
motor: 2.5L
Tires: 33x12.50 m/t
gearing: stock (4.11 i think)
no speedo cal yet
completely stock engine

about 14 in my calculations, but prolly a lil more since i don"t have a speedo cal yet
Title: Re: Official Gas Mileage Thread
Post by: dexetr30 on January 28, 2009, 08:09:43 AM
I noticed a big drop in m.p.g. in the past month or so. Probably for 2 reasons. 1. I need to replace the o2 sensor after the cat. and 2. I've had it in 4wd way more than usual because of all the ice, snow and general slop we've been getting for almost 4 weeks on a regular basis. I've gone from about 18 m.p.g. to around 15 or so m.p.g.  :'(
I can't wait for the big thaw!
Title: Re: Official Gas Mileage Thread
Post by: chardrc on January 28, 2009, 12:25:41 PM
mialage also drop when its cold.. I lose 5 mpg in the winter in my dd
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on January 28, 2009, 01:43:19 PM
mialage also drop when its cold.. I lose 5 mpg in the winter in my dd
Does your state switch over to a 'Winter Blend'?  If it does, then that's the reason.  Also, during winter, people use their heaters, wipers and lights more often which causes the alternator to charge more.  Although, I doubt that's measurable/
Title: Re: Official Gas Mileage Thread
Post by: The_Madness on January 31, 2009, 11:04:36 AM
I get around 14.4 in the summer time around town, but that drops down to 13.2 in the winter. However, I pull 20-25 on highway trips, and not flat highway - up and down hills at 40-55 mph.

Motor: 2.5 MPI
Engine Mods: Royal Purple Syn Oil, K&N Panel Filter
Tranny: 30RH 3 Speed Automatic
Gears: Stock gearing (3.73s from what I can find)
Tires: 29" Goodyear Wranglers
Weight: 3395 (if I can remember correctly) with hardtop and me in it
Aerodynamics: Like a brick
Title: Re: Official Gas Mileage Thread
Post by: chardrc on January 31, 2009, 09:19:50 PM
Does your state switch over to a 'Winter Blend'?  If it does, then that's the reason.  Also, during winter, people use their heaters, wipers and lights more often which causes the alternator to charge more.  Although, I doubt that's measurable/

the mpg is lost in the motor not being warmed up (as fast) resulting in a richer fuel ratio and a slightly higher idel... and when its really cold and i have to sit and let it warm up
Title: Re: Official Gas Mileage Thread
Post by: indyjeepnut on February 07, 2009, 10:47:33 AM
Debating on 456 or 488... 2.5 ax5 31's anyone running either of these combo's. With 488 I should be tacking 3k @ 65mph. 456 should be 2600. Which would be better gas mileage for street driving? From what I have read the 2.5 like to run around 3k.

Give me your thoughts
Title: Re: Official Gas Mileage Thread
Post by: FourbangerYJ on February 09, 2009, 10:20:06 AM
Tranny = AX5
Motor = 2.5L MPFI
Tire size = 37 (32psi)
Gearing = 5.38
Checked my speedo with a GPS it's on the money!
Engine mods = Rockit City intake tube with K/N. 4.0TB non bored intake. Flowmaster 50 series muffler.

My last run I checked my mileage. I got 12.9 MPG. This is doing 65-70 MPH thru some hills and flat HWY. I  :lol: real hard when one of the guys running a 4.0 XJ told me I was driving to fast and to keep it under 65MPH!

When I was running 4.88's and 35's I was getting about 10 MPG.

When I bore the intake and add the 62mm TB I will update.
Update With the 62MM TB I got 13.8 MPG. I drove the same route as my last gas mileage post.
Title: Re: Official Gas Mileage Thread
Post by: TahoeYJ on February 20, 2009, 09:36:23 AM
Filled up the other day and I've kept my foot out of the skinny pedal as much as possible to see what kind of mileage I truly get out of a tank. Granted this tank will be like 95% city driving, I'm anxious to see what I get, as my gas guage seems to be moving at a nice, slow rate  :dance:

Sometimes I forget how much better mileage I get when I don't drive the piss out of it  :ass:
Title: Re: Official Gas Mileage Thread
Post by: aka-justin on February 28, 2009, 09:15:13 AM
I get about 15 MPG in my 1995YJ.

AX5
2.5L 4 Banger!
31x12.5xR15 ProComp Mud Terrians
Stock 4.11 Gearing
No Speed Calibration, only off by 1 mph per 15.  When I'm doing 60 per the gauge, I'm going 64-65.
Only upgraded the TB to a 4.0 and did a tune up. (Spark Plugs, Oil and Filter, Air Filter, Fuel Filter, and Diff./Transmission/Axle Fluid Change)

Title: Re: Official Gas Mileage Thread
Post by: dexetr30 on March 20, 2009, 07:58:35 AM
My mileage is slowly making it's way back up to where it should be during the warmer months. I figure it's due to not having to warm it up for 10 minutes every morning and not having it in 4wd all the time.

Maybe I'm crazy but it seems like my mileage sucks when I use gas with 10% ethanol in it. Does this happen to anyone else?
Title: Re: Official Gas Mileage Thread
Post by: FourbangerYJ on May 26, 2009, 09:21:44 AM
Mileage went down to just over 11. The only thing I changed was swapping the soft top for a bikini and taking the K&N/Rockit city air intake tube off and swapping in a OE TJ intake box.
How much areo loss is there by going from a soft top to a bikini?
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on May 26, 2009, 11:59:33 AM
Mileage went down to just over 11. The only thing I changed was swapping the soft top for a bikini and taking the K&N/Rockit city air intake tube off and swapping in a OE TJ intake box.
How much areo loss is there by going from a soft top to a bikini?
A lot.  There is too much turbulence with no top or bikini top on.  Air gets sucked back into the Jeep from behind, air getting sucked in from the sides, etc...   I noticed a difference in mileage when I went from Soft top to a hard top even though the hardtop adds weight.  The hardtop has a slicker surface so there is less for teh wind to grab, not to mention it's 2" shorter then the softtop.  The softtop inflates at higher speeds which also increases it's size.  The flapping doesn't help either.  BUT this is at higher speeds.  Aerodynamics come into play at speeds higher then 35MPH.  At 55MPH it's not too bad, even 60MPH but start pushing it to 70 or higher and you'll start to hit the proverbial brick wall.

I've mentioned this before but I played around, removing a bunch of weight and noticed no difference at highway speeds in mileage.  I removed my rear bumper, rear seat, spare, spare mount, passenger side mirror, winch, winch plate, aux lights etc and noticed very little is any difference at highway speeds.  I did notice it was quicker from a stand still.

Also when I was playing around with the intake and exhaust, I noticed I have more torque with the stock air box and my Borla.  I was running a K&N open element and I was able to REV more freely but there wasn't as much torque at the low or mid.  I had more HP at the top end though.  I also noticed when I punched a 2" tear in my exhaust right after teh muffler,  I had less torque but had more HP at the top end.  It was enough to feel the difference.
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on May 26, 2009, 12:22:14 PM
Maybe I'm crazy but it seems like my mileage sucks when I use gas with 10% ethanol in it. Does this happen to anyone else?
Yes, ethanol reduces your mileage.
Title: Re: Official Gas Mileage Thread
Post by: jfrabat on May 26, 2009, 12:33:47 PM
Yes, ethanol reduces your mileage.

Correct; ethanol has less energy than gas, hence you need to consume more to get the same power...
Title: Re: Official Gas Mileage Thread
Post by: FourbangerYJ on May 26, 2009, 02:14:54 PM
A lot.  There is too much turbulence with no top or bikini top on.  Air gets sucked back into the Jeep from behind, air getting sucked in from the sides, etc...   I noticed a difference in mileage when I went from Soft top to a hard top even though the hardtop adds weight.  The hardtop has a slicker surface so there is less for teh wind to grab, not to mention it's 2" shorter then the softtop.  The softtop inflates at higher speeds which also increases it's size.  The flapping doesn't help either.  BUT this is at higher speeds.  Aerodynamics come into play at speeds higher then 35MPH.  At 55MPH it's not too bad, even 60MPH but start pushing it to 70 or higher and you'll start to hit the proverbial brick wall.

I've mentioned this before but I played around, removing a bunch of weight and noticed no difference at highway speeds in mileage.  I removed my rear bumper, rear seat, spare, spare mount, passenger side mirror, winch, winch plate, aux lights etc and noticed very little is any difference at highway speeds.  I did notice it was quicker from a stand still.

Also when I was playing around with the intake and exhaust, I noticed I have more torque with the stock air box and my Borla.  I was running a K&N open element and I was able to REV more freely but there wasn't as much torque at the low or mid.  I had more HP at the top end though.  I also noticed when I punched a 2" tear in my exhaust right after teh muffler,  I had less torque but had more HP at the top end.  It was enough to feel the difference.

Good to know. I have run the bikini for so many years all year, then last fall I got a soft top. Good info THANKS!
Interesting on the weight study. I thought for sure that on the top end a lighter Jeep would beable to have a higher top speed. Make sense getting off the line.
I have always gotten fairly low mileage around 10. I was kinda shocked that I was getting in the 13's. I had not realized that the type of top you run makes such a differance in mileage.
Title: Re: Official Gas Mileage Thread
Post by: Bill M. on June 02, 2009, 12:55:05 PM
A lot.  There is too much turbulence with no top or bikini top on.  Air gets sucked back into the Jeep from behind, air getting sucked in from the sides, etc...   I noticed a difference in mileage when I went from Soft top to a hard top even though the hardtop adds weight.  The hardtop has a slicker surface so there is less for teh wind to grab, not to mention it's 2" shorter then the softtop.  The softtop inflates at higher speeds which also increases it's size.  The flapping doesn't help either.  BUT this is at higher speeds.  Aerodynamics come into play at speeds higher then 35MPH.  At 55MPH it's not too bad, even 60MPH but start pushing it to 70 or higher and you'll start to hit the proverbial brick wall.

I've mentioned this before but I played around, removing a bunch of weight and noticed no difference at highway speeds in mileage.  I removed my rear bumper, rear seat, spare, spare mount, passenger side mirror, winch, winch plate, aux lights etc and noticed very little is any difference at highway speeds.  I did notice it was quicker from a stand still.

Also when I was playing around with the intake and exhaust, I noticed I have more torque with the stock air box and my Borla.  I was running a K&N open element and I was able to REV more freely but there wasn't as much torque at the low or mid.  I had more HP at the top end though.  I also noticed when I punched a 2" tear in my exhaust right after teh muffler,  I had less torque but had more HP at the top end.  It was enough to feel the difference.

Sorry to bring up an old thread, but why did you induce an exhasut leak?? I would think a small horsepower gain for a exhasut leak wouldnt be a good idea!
Title: Re: Official Gas Mileage Thread
Post by: Jeffy on June 04, 2009, 04:28:47 PM
Sorry to bring up an old thread, but why did you induce an exhasut leak?? I would think a small horsepower gain for a exhasut leak wouldnt be a good idea!
I did not induce one it just sort of ripped open.   :uhoh:  Ended up with a 2" tear, 1/2" wide in the pipe right after the muffler.  It wasn't ideal since the increase of HP was at the expensive of low end torque.
Title: Re: Official Gas Mileage Thread
Post by: chrisfranklin on July 24, 2009, 12:43:57 PM
My 4Banger can now "out-drink" a big V8!  :lol:
Title: Re: Official Gas Mileage Thread
Post by: spoonman on August 18, 2009, 08:03:26 AM
since gas has been cheap all summer, i have been driving my jeep for my daily commute. it's 100 miles with mostly highway. i've not been easy on it and going 70+ on the freeway. i'm still getting 19.5. i think this week i'll try hypermiling the jeep. my jeep is stock except for panel filter and cat back. eventually i'll get a 4.0 tb when davey's gets one in. the tires are stock too.  it's not an offraod jeep b/c i need it as a 3rd vehicle. it gets alot worse mileage than my hyundai accent (46) , but is something a can live with.
Title: Re: Official Gas Mileage Thread
Post by: 93yjFirstJeep on August 18, 2009, 05:15:25 PM
with my 4.88's, half worn 33x12.50 procomp muds, stock air filter, hi flo cat and catback,
about 19-20 if i keep her below 55
about 14-16 if i drive 70
really sucks considering my commute to college is goin to be 90 miles each way once a week  :brick:
Title: Re: Official Gas Mileage Thread
Post by: stan98tj on August 28, 2009, 02:03:04 PM
how are you guys gettin upwards of 18+ mpg while hauling 32"+ tires????? im hauling 31s, stock gearing, and a few bolt on "performance" parts and im getting at best 12-13...maybe 14 on a good day. id kill for 18+.  i have yet to bore out the intake port on the engine to match the 62mm....but i doubt it's what is killin me.  I used to get around 9mpg when i first bought it, the AEM intake brought it to around 13-14.  Maybe the injectors are shot? fuel regulator? id love my jeep to see 18-19mpg.
Title: Re: Official Gas Mileage Thread
Post by: sharpxmen on August 28, 2009, 10:49:50 PM
how are you guys gettin upwards of 18+ mpg while hauling 32"+ tires????? im hauling 31s, stock gearing, and a few bolt on "performance" parts and im getting at best 12-13...maybe 14 on a good day. id kill for 18+.  i have yet to bore out the intake port on the engine to match the 62mm....but i doubt it's what is killin me.  I used to get around 9mpg when i first bought it, the AEM intake brought it to around 13-14.  Maybe the injectors are shot? fuel regulator? id love my jeep to see 18-19mpg.
4.10 and 33s and the pedal to the floor on the hwy i was getting 13 mpg. If you slow down you'll improve your mpg substantially and gearing will help as you will be able to use 5th more efficiently. The jeep is as aerodynamic as a brick, so it hurts badly when you speed up.
Title: Re: Official Gas Mileage Thread
Post by: TahoeYJ on September 16, 2009, 12:21:21 PM
Been doing a lot of driving lately, lots of like 150-200 mile round trips. Yesterday and today I had to make a 125 mile round trip to follow my uncle up to the dealership he bought his Harley at and drive him back, and again to pick it up today. Doing an average of about 68-70 most of the way I used right around a half a tank, which puts me at a hair over 17 MPG. There's some short inclines in some places, where I had to downshift to 4th to maintain 70, but my foot still wasn't planted to the floor in 4th. I just wanted to maintain speed.

As of now, this is what I've done performance wise...

Magnaflow XL muffler, 2.25" tailpipe
Carsound high-flow cat
4.0 TB
19# Design III injectors
MSD Blaster Coil, plugs re-gabbed to .050
Minor porting on the intake manifold ports
And recently added, Rock-It intake w/ a K&N

I'm pretty happy with the mileage, as long as I keep it at about 70 max 16-17 is easy to get with the hard top on. My next performance mod will be a 4.0 TB spacer, and perhaps a header down the road. I've also got the intake manifold from my old motor I've been slowly doing port work on, I've almost got it cleaned up enough to slap back on. Don't know how much of a difference it will make but WTH  :confused:

Dunno if it makes a difference with mileage or not, but my oil has a good 3500+ HARD driven miles on it. I haven't exactly been easy on the old girl lately  :whistle:
Title: Re: Official Gas Mileage Thread
Post by: IdahoXJ on September 16, 2009, 01:30:19 PM
Currently getting 21mpg. My 1993 XJ is a bone stock "base" model with no engine or exhaust mods. I run Toyo 235/75R15 tires (29.5" dia) on AWC white spoke steel rims. There are 167889 miles on the odo. I drive a mix of highway and secondary roads (paved) varying from 50 to 65mph, around 50 to 75 miles a day.

The only major work I've done so far is replace the timing set, cam and lifters with stock units. The originals were damaged by a sheared off cam drive gear to cam locater pin which ruined the cam and cam drive gear.

Other than that, a complete and through tune-up is it.

I plan a 4.0L TB with spacer in the near future along with removing the mechanical fan and replacing it with a electric unit.

Cheers.
Title: Re: Official Gas Mileage Thread
Post by: SoPo94YJ on September 22, 2009, 08:44:47 PM
94 Wrangler, k&n filter, Airaid throttle body spacer, 4.10's, 6" total lift,35's 95k miles, with my stock speedo gear it wont read past 55 down hill with the wind at my back and i cant touch 5th gear (havent used it in months) Im guessing it would be about 60 maybe a little more with speedo correction. i get about 130 miles to a full tank :). 15 gallon tank? and the odo is a little off... 10 maybe 12mpg haha...yeah big things coming soon
Title: Re: Official Gas Mileage Thread
Post by: dwtaylorpdx on September 24, 2009, 12:08:21 PM
94 Yj
2.5 built out 10.8 :1 Hesco cam (RV)
Stock air cleaner
4.0 TB with 7/8 smooth bore spacer.
GC injectors (6 cyl)
AX5 tranny
235x85-16 tires.
4.56 gears.
heavy accessory load (Bumpers, winch etc.)

was getting 10 with 285x75-16 tires the 235 put me back up to 15~16.
Just did a 1200 mile road trip to Colorado.

Dave
Title: Re: Official Gas Mileage Thread
Post by: Sine Deviance on October 04, 2009, 09:54:17 PM
I just added a performance intake yesterday. So I'll post what I was getting before that.

'95 YJ, Rio Grande edition
158,000 miles
Stock 2.5L
Stock manual trans
Stock 4.10's
Stock exhaust with what seems to be a small leak, dunno where yet
2" Black Diamond lift
31x10.5 BFG A/T's (Not sure if speedo was recalibrated. The guy that owned it before me did most of the mods and he spared no expense, and by judging from traffic, I'm pretty sure it was.)
x4 PIAA HALO Daylighters on a Carr Rota lightbar that is always up

I do a mix of City/Highway driving, mostly City. I calculated my fuel usage from a totally full tank of gas to "on the E" and came up with 16mpg.

After I get some more engine mods and the e-fan I'll post again with the new results. I expect them to be closer to 20, if not over.
Title: Re: Official Gas Mileage Thread
Post by: jfrabat on October 07, 2009, 08:34:59 AM
I just added a performance intake yesterday. So I'll post what I was getting before that.

'95 YJ, Rio Grande edition
158,000 miles
Stock 2.5L
Stock manual trans
Stock 4.10's
Stock exhaust with what seems to be a small leak, dunno where yet
2" Black Diamond lift
31x10.5 BFG A/T's (Not sure if speedo was recalibrated. The guy that owned it before me did most of the mods and he spared no expense, and by judging from traffic, I'm pretty sure it was.)
x4 PIAA HALO Daylighters on a Carr Rota lightbar that is always up

I do a mix of City/Highway driving, mostly City. I calculated my fuel usage from a totally full tank of gas to "on the E" and came up with 16mpg.

After I get some more engine mods and the e-fan I'll post again with the new results. I expect them to be closer to 20, if not over.

Dont get your hopes up so much; mine was still in the 16mpg range even with the e-fan, 4.88 gears, all the mods and 31's...
Title: Re: Official Gas Mileage Thread
Post by: Sine Deviance on October 10, 2009, 07:19:17 PM
Dont get your hopes up so much; mine was still in the 16mpg range even with the e-fan, 4.88 gears, all the mods and 31's...

It's actually already better. With the intake and TB swap I recalculated my fuel usage for the past week. Again, from a full tank to "on the E." I came up with 18mpg.

I'm going to assume that it will only get better with a new header/high-flow cat and the E-fan. People tell me the high-flow cat is the most important part.
Title: Re: Official Gas Mileage Thread
Post by: radark1 on December 03, 2009, 11:40:35 AM
140 miles per tank. I have a 92 YJ, 4banger,....4.88 gears, 33" tires, stock tranny and transfer case. MILEAGE SUCKS!
Title: Re: Official Gas Mileage Thread
Post by: dwtaylorpdx on December 05, 2009, 10:27:49 PM
94 Yj
2.5 built out 10.8 :1 Hesco cam (RV)
Stock air cleaner
4.0 TB with 7/8 smooth bore spacer.
GC injectors (6 cyl)
AX5 tranny
235x85-16 tires.
4.56 gears.
heavy accessory load (Bumpers, winch etc.)

was getting 10 with 285x75-16 tires the 235 put me back up to 15~16.
Just did a 1200 mile road trip to Colorado.

Forgot to put in my Headers = Thorley, 2.5 inch exhaust all the way, High flow matrix cat. spintec muffler.

Dave

Title: Re: Official Gas Mileage Thread
Post by: jfrabat on January 05, 2010, 01:41:36 PM
140 miles per tank. I have a 92 YJ, 4banger,....4.88 gears, 33" tires, stock tranny and transfer case. MILEAGE SUCKS!

Did you do the tank mod to get the 20 gals out of the tank?  I get almost 300 miles out of mine (94 with 33's and 4.88 also).
Title: Re: Official Gas Mileage Thread
Post by: sharpxmen on January 05, 2010, 09:01:26 PM
Did you do the tank mod to get the 20 gals out of the tank?  I get almost 300 miles out of mine (94 with 33's and 4.88 also).

my guess is he's on the small tank and never accounted for the difference in speedo/mileage with the larger tires, otherwise he'd be at 7mpg which means he's leaking fuel or something's very wrong.
Title: Re: Official Gas Mileage Thread
Post by: tony_dt on January 08, 2010, 07:05:05 PM
JEEP: 2001 TJ
Motor: 2.5
Engine Mods: Banks Header, Exhaust, Aftermarket Cat, AirRaid, Rebuilt Motor (Different Block and heads)
Oil: Amzoil 0-30
Tranny: Stock
Gears: Stock gearing
Tires: 30"
Softtop, with full doors.

I made a few additions that really improved my gas mileage. I replaced the stock CAT and the whole exhaust with  Banks Exhaust and some cheap CAT. I also added full doors. Not sure if that helped or hurt. I have had my jeep since almost new (12000mi) and the best mileage I could get on the hiway was 21 when new with stock tires and this dropped as the motor got older to 18, 16 and sometimes 12. On the way back from Des Moines a few weeks ago, I was getting 24.6 on two fillups. (I don't use the speedo as it is wrong, I used GPS). I had some tailwind so I am sure that was some of it but I am very pumped about the mileage now. I get consistantly get 20 going back in forth from work, which is mostly old farm roads.


Title: Re: Official Gas Mileage Thread
Post by: mrcabinet on February 05, 2010, 08:10:11 AM
2001 TJ, Hardtop, 2.5, 5 spd., 4.56 gears, 33x12.50 BFG ATs.
4" lift, Flowmaster exhaust, Airaid intake, 62mm TB & spacer.

Combined mileage before the TB/Spacer was 13.9. After, it went to 15.3.
I'm pleased, since I have more power along with better gas mileage. Hopefully
when I do an e-fan this spring it will improve a little more.
Title: Re: Official Gas Mileage Thread
Post by: hotwired on February 14, 2010, 11:56:40 AM
 Around 14MPG with stock 97 TJ 2.5L, 4:88's and 35" MTR's, speedo is re-calibrated.
Title: Re: Official Gas Mileage Thread
Post by: Lu on March 08, 2010, 11:13:11 AM
2.5L, Ax-5, Stock gearing, 31's, hard top, 4.0L TB, spacer, airaid CAI, royal purple oil, magnaflow exhaust, accel coil powering bosch platinum +4 plugs, small shackle lift, recent tune-up,

between 16 and 18 mpg

Title: Re: Gas Mileage
Post by: Jeffy on April 17, 2010, 09:37:59 PM
Just wanted to update.  With the Con-Ferr rack on top the Jeep's mileage dropped 1.4MPG as expected.  Still averaging 15MPG with mixed driving otherwise.
Title: Re: Gas Mileage
Post by: firebrick43 on April 25, 2010, 10:53:13 AM
When I bought the Jeep I was getting 18mpg

I am now getting 23MPG in mixed driving(20 miles of 55mph two lane hiway normally at 60mph, and 10 miles of city stop and go at ~30 mph)

I have a 91 2.5 with every thing now working correctly. Replacing several vacuum lines that were leaking(especially the one the fuel pressure regulator, and fixing an exhaust manifold leak saw me get to 20MPG.   Mobile 1 in the engine but have not put synthetics in the tranny/rear ends.  Using a 4.0 TB and boring out the intake manifold Saw a significant gain in power and a 1-2 mpg increase in fuel economy. 

I am running 235/75R15 Michiline's LTX with stock gearing which is a 29" tire if I recall correctly, this got me 1mpg to 23. 
Title: Re: Gas Mileage
Post by: jfrabat on April 25, 2010, 04:36:40 PM
Jesus, it seems that everyone's mpg's keep going UP and mine keep going DOWN!  I guess I'mm adding all the wrong parts for mpg...  BUT, then again the Jeep is no t a daily driver, so I ratehr go for power than mpg now.  Still, I know there is room to improve, as I can still smell a faint gasoline smell when I fill up the tank, so I'm sure there is a small leak SOMEWHERE above the tank (already tried twice to lower it and fix it, but no luck so far!  At least it's a very FAINT SMELL, and no liquid is seen spilling; it's only fumes coming out if you ask me, and you can only smell it if I park the Jeep in the garage and stick your nose in the fenderwell behind the DS rear wheel.)
Title: Re: Gas Mileage
Post by: chardrc on April 25, 2010, 05:08:39 PM
ive also noticed that my my front driveshaft is totaly free in 2wd. when a customer had me look at there 01 tj the front driveshaft and axles were always engaged even in 2wd except the transfer case isnt lock'd.

that's what the vacuum disconnect on the passenger side of the front axle is for. supposed to increase mpg by having less rotating stuff, but they eventually found it cost more than they thought it was worth and stopped having the disconnects when they made the TJ.
Title: Re: Gas Mileage
Post by: Jeffy on April 25, 2010, 05:29:37 PM
Jesus, it seems that everyone's mpg's keep going UP and mine keep going DOWN!  I guess I'mm adding all the wrong parts for mpg...  BUT, then again the Jeep is no t a daily driver, so I ratehr go for power than mpg now.  Still, I know there is room to improve, as I can still smell a faint gasoline smell when I fill up the tank, so I'm sure there is a small leak SOMEWHERE above the tank (already tried twice to lower it and fix it, but no luck so far!  At least it's a very FAINT SMELL, and no liquid is seen spilling; it's only fumes coming out if you ask me, and you can only smell it if I park the Jeep in the garage and stick your nose in the fenderwell behind the DS rear wheel.)
Drive slower and your mileage will increase.  55mph is a pretty good compromise for mileage v. speed.  Go faster and the mileage will take a quick dive.

If you can smell it in the fender well then it's probably the 90* rubber tube on the fuel filter.
Title: Re: Gas Mileage
Post by: jfrabat on April 25, 2010, 08:02:43 PM
If you can smell it in the fender well then it's probably the 90* rubber tube on the fuel filter.

It's actually the rollover valves; i can see where it leaks a bit, but I cannot get them to stop leaking.  Next time I drop the tank, I may end up using some RTV there...
Title: Re: Gas Mileage
Post by: firebrick43 on April 25, 2010, 09:35:37 PM
Most RTV is not fuel resistant.  The make potting compounds and non hardening sealers for fuel systems. 
Title: Re: Gas Mileage
Post by: Jeffy on April 25, 2010, 10:07:55 PM
Buy new breather line and replace them completely.    Otherwise, cut and re insert.
Title: Re: Gas Mileage
Post by: jfrabat on April 26, 2010, 08:31:28 AM
Buy new breather line and replace them completely.    Otherwise, cut and re insert.

That's what I did the last time, but it seems the gromet for the plastic valve is the one leaking...
Title: Re: Gas Mileage
Post by: FourbangerYJ on May 02, 2010, 11:26:37 AM
Last trip out was just a tad over 13 MPG. This will drop to about 11 when I take the soft top off. Seems the adjustable FPR has not changed my mileage.
Title: Re: Gas Mileage
Post by: Jeffy on May 04, 2010, 07:21:31 PM
tires make a big difference on fuel mileage. My non winter tires are toyo open country's. winter tires are firestone winterforces. with the winter force i was down to only 16mpg city or highway. also I run 5w-30 motor oil. lighter engine oil can slightly improve fuel mileage as well. 5w-30 is all i ever ran. using a 10-30 or 10-40 i wouldn't actually know how much of a difference it would make fuel mileage wise. but once i poured a whole bottle of STP in my subaru and that really slow'd the engine down. least it toke care of a bad valve tap in that motor til i sold  it.
Also, some states change the blend of their fuel so you end up getting less mileage as well.

All I run is mobile 1 5w30.
Title: Re: Gas Mileage
Post by: aka-justin on May 08, 2010, 01:20:32 AM
Update:

After replacing my TPS sensor and accounting for the difference in mileage for a 31" tire, my last tank of gas with mainly city to small amounts of highway, easy driving was 15.7 MPG!!!  Much better than my inital 10-12 I was receiving before recalculating for difference in tire size and bad TPS unit.  :naughty:
Title: Re: Gas Mileage
Post by: vprsrul on June 11, 2010, 09:25:54 AM
89 4banger ax-5 4:10 gears with 33/12.50r15 interco all terrains with a close to correct speedo gear(reads about 58-59 at 60mph per gps)  214,000 miles with all original drivetrain never rebuilt.  i return between 14-18 mpg according to jp's trip but that would be slightly less than actual as the speedo gear is a tad slow.  she used to have 10-30 now I run straight rotella sae30 with no decrease in mpg whatsoever with only wix filters.  still no oil leaks or use from the motor.  If I keep the 4banger I will switch to amsoil.
Title: Re: Gas Mileage
Post by: sharpxmen on June 23, 2010, 05:54:06 PM
33x12.50's how well does that pull with stock axle ratio's?

not that great but you can live with it (i did have exactly that, 33s and 4.10 and was usable but forget 5th).
Title: Re: Gas Mileage
Post by: RT on June 24, 2010, 08:36:28 PM
i usually get around twenty with the 225's, when i baby it I can push it to 23-24  :bandit:
Title: Re: Gas Mileage
Post by: RT on July 01, 2010, 10:24:32 AM
Drove an stock 89 yj 2.5 with 5inches SUA lift with 33/10.50's yesterday. WASNT SO BAD! :doggy:

I have a friend with a 91, 5 inch lift, and 33's...it runs fine but he eats a clutch every sick months :fitz:
Title: Re: Gas Mileage
Post by: Torch_Ind on July 02, 2010, 10:29:51 AM
I have a friend with a 91, 5 inch lift, and 33's...it runs fine but he eats a clutch every sick months :fitz:


stop riding the cluch then.    I bough mine of my parents with the original clutch and lifted it and have drove it 2 years now with 33x12.5r15's.  I put a performance clutch in that one lasted a month so went back to my stock used one and still going with that one!!

p.s Zoom performance clutches suck balls!!!
Title: Re: Gas Mileage
Post by: chrisjsmith4 on July 10, 2010, 10:36:37 PM
I have a 2003 2.4L nv1500/2550 what ever you wanna call it. 4:10 gears (stock). stock engine was getting 20 mix highway/city on 235, added turbo and lost a few, went down to 18-19 on 235; added 3.5 in lift and 33's getting 14 mpg. shocked at the difference. The turbo helps. I can put it in 5th on the freeway but forget about accelerating unless it is downhill. 1st through 4th gets up and moves though.

I'm thinking about doing a 6speed swap in the future. The 6 speeds come with 3:73 stock. If I do that but keep my 4:10 will it be the same result as the stock tranny and 4:56 or 4:88?
Title: Re: Gas Mileage
Post by: sharpxmen on July 11, 2010, 12:05:27 AM
I have a 2003 2.4L nv1500/2550 what ever you wanna call it. 4:10 gears (stock). stock engine was getting 20 mix highway/city on 235, added turbo and lost a few, went down to 18-19 on 235; added 3.5 in lift and 33's getting 14 mpg. shocked at the difference. The turbo helps. I can put it in 5th on the freeway but forget about accelerating unless it is downhill. 1st through 4th gets up and moves though.

I'm thinking about doing a 6speed swap in the future. The 6 speeds come with 3:73 stock. If I do that but keep my 4:10 will it be the same result as the stock tranny and 4:56 or 4:88?

did you account for the difference in odometer readings? it's about 15% with 33s so that will throw off your mpg calculations
Title: Re: Gas Mileage
Post by: Mozman68 on July 11, 2010, 12:17:10 PM
My last two tanks (since the TPs, CPS and electric fan install) have both been 15.5 mpg.....I'm going to check on a regular basis from now on to verify.  Was running as low as high 13's/low 14's pretty consistently before.  Could get into 15's if it was 100% highway.
Title: Re: Gas Mileage
Post by: chrisjsmith4 on July 11, 2010, 12:33:27 PM
If it is a 15% difference then I probably got around 16 mpg. Not really too bad but I can watch my needle drop when I go down the freeway. Its kind of a sinking feeling lol.
Title: Re: Gas Mileage
Post by: Complete Loser on August 04, 2010, 10:05:00 PM
17-18mpg of 87octane (city),
(mpg of oil yet to be determined),

92' ragged out 2.5L FI.
tbs, Performance Dist ignition kit, 4.0tb, Pacesetter header, 2 mufflers,
30" tires
no speedo calibration,
Ax5/np231
4:11/4:10
Startron fuel additive in every tank,
130amp alt,
new wipers.

One thing to consider on gas mileage that alot of folks forget is time sitting in the drive thru.  :beer:


Title: Re: Gas Mileage
Post by: karan on February 12, 2011, 10:04:58 AM
18 mpg with mostly city driving- live in downtown and work just out of it, drive 26 km every day to and fro with plenty of red lights and average moving traffic
*15 mpg with mostly city driving- live in downtown and work just out of it, drive 26 km every day to and fro with plenty of red lights and average moving traffic

As you notice i have two mpgs reported here, i do like the figure 18 mpg but its at the cost of looks of my jeep so i am going back to bigger tires this week, 30 9.50 15 was giving me 15 mpg which i think i can live with, at least it doesnt make my jeep look robbed of its natural beauty :)
 
Transmision Type Manual
gine Type AMC 2.5L MPFI
Tire Size 205/75/15
*Tire Size 30 9.50 15
Differential Gearing Stock
Speedometer Calibration (N)
List of ENGINE Mods - Cat back Exhaust System


As y
Title: Re: Gas Mileage Thread
Post by: Torch_Ind on March 07, 2011, 12:47:23 PM
did over 3 hour trip and managed to get some miles/fuel used between fuel stations. this is I will say 80-90% highway.. 10-15% town or idle.. 5% drifting some corners and playing on a back road at my parents lol..

anyway here is what I came up with.


Fuel Cost
     $68
 
Distance travelled
      291     km
      180.83     miles
 
Fuel Amount
      53.17     litres
      14.05     US gallons
      11.7     Imperial gallons
Cost of Fuel
 $1.28         per litre
 $4.84         per US gallon
 $5.81         per Imperial gallon
 
Fuel Economy
18.27
        litres per 100 km
12.87
        miles per US gallon
15.46
        miles per Imperial gallon
 
Mileage Costs
23.3677        ¢ents per km
37.6        ¢ents per mile


I think I could get better because the road I took has several large grade hills!! and I was also driving in extreme winter weather conditions!!

my next fill up I'm hopping to get 50% highway "took 1/2 tank to get home from last fuel station" and 50% city/idling to see what I come up with. oh and I plowed once already.  so I'm curious what I get doing some minor highway & my typically town driving it normally does..

Title: Re: Gas Mileage Thread
Post by: stan98tj on March 12, 2011, 04:03:51 PM
I hate all of you who are getting 18 and over...i REALLY hate you guys getting over 20..my jeep won't even get that parked with the motor OFF lol. Going from 31s to 33s didnt hurt me too bad in the mpg department. still 13-15. 15 on a real good day. I got 17 once (i DO NOT know how the hell that happened).
By the way has anyone seen these clips on youtube about Hydrogen boost to boost mpgs? I posted about it a while ago. Now with the increasing gas prices i've begun seeing more and more of these clips. Dateline NBC did a report on one manufacturer in particular who claimed increases and his product didnt work at all. But there seem to be many ppl who claim they do work.
here is a clip of a guy claiming 36mpgs on his wrangler:
http://www.youtube.com/v/7ireXlV7m-k
i dont know how to embed it
Title: Re: Gas Mileage Thread
Post by: Jeffy on March 12, 2011, 04:24:46 PM
I hate all of you who are getting 18 and over...i REALLY hate you guys getting over 20..my jeep won't even get that parked with the motor OFF lol. Going from 31s to 33s didnt hurt me too bad in the mpg department. still 13-15. 15 on a real good day. I got 17 once (i DO NOT know how the hell that happened).
By the way has anyone seen these clips on youtube about Hydrogen boost to boost mpgs? I posted about it a while ago. Now with the increasing gas prices i've begun seeing more and more of these clips. Dateline NBC did a report on one manufacturer in particular who claimed increases and his product didnt work at all. But there seem to be many ppl who claim they do work.
here is a clip of a guy claiming 36mpgs on his wrangler:
http://www.youtube.com/v/7ireXlV7m-k
i dont know how to embed it

It's the flames.  They add 20HP and raise the MPG 10-15 MPG.  I think he's got JATO rockets as nerfs as well.
Title: Re: Gas Mileage Thread
Post by: Torch_Ind on March 12, 2011, 05:29:27 PM
I hate all of you who are getting 18 and over...i REALLY hate you guys getting over 20..my jeep won't even get that parked with the motor OFF lol.


really I get 15 with mods and 6inches of lift 4.88's and 33's with open front fenders and a bit top light bar.. I could prob squeeze 17ish if I was easy on it in nice weather and flat strait roads.

also I did a mpg check when I was stock with 31's pulling a small trailer with a min z on it. and all our gear in the jeep we got roughly 22mpg

what do you got for a build ??
also do you run a/c
let it idle a lot?
clutch fan stuck?
Title: Re: Gas Mileage Thread
Post by: stan98tj on March 13, 2011, 09:04:18 AM
really I get 15 with mods and 6inches of lift 4.88's and 33's with open front fenders and a bit top light bar.. I could prob squeeze 17ish if I was easy on it in nice weather and flat strait roads.

also I did a mpg check when I was stock with 31's pulling a small trailer with a min z on it. and all our gear in the jeep we got roughly 22mpg

what do you got for a build ??
also do you run a/c
let it idle a lot?
clutch fan stuck?

stock fan. no a/c. auto, 33s, stock gears. Im just saying, it's like driving a barn...20+mpg is a lot more rare with these wranglers, i would think.
Title: Re: Gas Mileage Thread
Post by: Torch_Ind on March 13, 2011, 09:07:23 AM
stock fan. no a/c. auto, 33s, stock gears. I'm just saying, it's like driving a barn...20+mpg is a lot more rare with these wranglers, i would think.

ditch the stock fan go electric also get bigger gears won't have to work as hard on take off. also auto robs more power then stick "I'm stick"  being your lifted on 33's I would say you may never see 20mpg's again.

drop to 31's with stock gears and you would get just over the 20mpg range.

I got the 15 but the weather was extremely bad and the road I had to take it was full of step grade hills and did a little town driving so I was impressed I got 15mpg's 

this summer when the weather is nice I want to do a south trip from were I am to see if I can hit the 20mpg or close to 20mpg because it's all flat strait road going south and they have blasted through most of the step grade hills.
Title: Re: Gas Mileage Thread
Post by: Jeffy on March 13, 2011, 12:00:20 PM
stock fan. no a/c. auto, 33s, stock gears. Im just saying, it's like driving a barn...20+mpg is a lot more rare with these wranglers, i would think.
How fast are you driving?
Title: Re: Gas Mileage Thread
Post by: stan98tj on March 13, 2011, 08:19:12 PM
How fast are you driving?
55-60mph. i think 15mpg is normal though...id love to hit 18+ but im not too sure how those ppl are getting that (esp those with larger lifts and tires than i). but then again, the dude in that clip i posted is getting 36mpg!!!!!! lol
Title: Re: Gas Mileage Thread
Post by: Jeffy on March 13, 2011, 08:31:03 PM
55-60mph. i think 15mpg is normal though...id love to hit 18+ but im not too sure how those ppl are getting that (esp those with larger lifts and tires than i). but then again, the dude in that clip i posted is getting 36mpg!!!!!! lol
Did you recalibrate your speedometer?  That would make a difference.  15MPG is what I get but then I push my Jeep a little and get it up to 70mph on bursts.  I also do a lot of short (6 mile) trips during the week.

I get as low as 14mpg but I average 15mpg.  That's calculated over several years.  When I was driving on the highway more (40 miles), I'd get 18mpg though.

Honestly though, if you want to get better gas mileage you will need to reaccess your priorities.  Things like, if you're driving offroad enough to need 33x12.5R15's.  Skinny 33's or 31's would probably help a lot.  Wider flares, crawler fenders, and a lot of other stuff that help offroad will really hinder your mileage as well.
Title: Re: Gas Mileage Thread
Post by: Torch_Ind on March 14, 2011, 03:53:29 PM
Did you recalibrate your speedometer?  That would make a difference.  15MPG is what I get but then I push my Jeep a little and get it up to 70mph on bursts.  I also do a lot of short (6 mile) trips during the week.

I get as low as 14mpg but I average 15mpg.  That's calculated over several years.  When I was driving on the highway more (40 miles), I'd get 18mpg though.

Honestly though, if you want to get better gas mileage you will need to reaccess your priorities.  Things like, if you're driving offroad enough to need 33x12.5R15's.  Skinny 33's or 31's would probably help a lot.  Wider flares, crawler fenders, and a lot of other stuff that help offroad will really hinder your mileage as well.

ya I'm open tube fenders now to
Title: Re: Gas Mileage Thread
Post by: stan98tj on March 14, 2011, 04:32:37 PM
  When I was driving on the highway more (40 miles), I'd get 18mpg though.
i just drove down to baltimore ~300 miles and got ~15mpg. Even when i had the 31s it was 15, maybe 16mpg.  What size tires were you running when you were getting 18mpg? I've been thinking of doing an e-fan mod, but im not sure if it helps all that much. Also maybe ditching the AEM cold air intake for a snorkel..again im not sure if it will help much
Title: Re: Gas Mileage Thread
Post by: Jeffy on March 14, 2011, 04:49:37 PM
i just drove down to baltimore ~300 miles and got ~15mpg. Even when i had the 31s it was 15, maybe 16mpg.  What size tires were you running when you were getting 18mpg? I've been thinking of doing an e-fan mod, but im not sure if it helps all that much. Also maybe ditching the AEM cold air intake for a snorkel..again im not sure if it will help much
I've got 35x12.5R15's and 4.56:1 gears.  But I was getting 18MPG before I ever did the eFan.

Are you running 33's with 3.73:1 gears?  What's your crusing RPM and speed?
Title: Re: Gas Mileage Thread
Post by: stan98tj on March 15, 2011, 02:31:47 PM
I've got 35x12.5R15's and 4.56:1 gears.  But I was getting 18MPG before I ever did the eFan.

Are you running 33's with 3.73:1 gears?  What's your crusing RPM and speed?
yes with 3.73s. 65mph is under 3k. around 2750-2800
Title: Re: Gas Mileage Thread
Post by: sharpxmen on March 15, 2011, 03:14:03 PM
yes with 3.73s. 65mph is under 3k. around 2750-2800

it that with the converter locked? how far down you have the pedal?
Title: Re: Gas Mileage Thread
Post by: RT on March 15, 2011, 07:13:25 PM
With exhaust, throttle, intake, cleaned fuel injectors and a lift with 30" tires I'm doing pretty good. I'm at just over a quarter tank left with 200miles on the odometer....we'll see how that turns out
Title: Re: Gas Mileage Thread
Post by: stan98tj on March 15, 2011, 11:55:46 PM
it that with the converter locked? how far down you have the pedal?
half throttle. i will be driving home on friday. my speedo isnt recalibrated, but i have a gps unit. ill pay closer attention to my rpms at 60-65. but i know for a sure that cruising at 65mph with my current equipment (33s, 3.73gears,3spd auto, 62mm tb, CAI, header/exhaust/hi-flo cat) i am under 3k (maybe 2750-2800) and i am around 15mpg. i will pay closer attention when i head home on friday.
Title: Re: Gas Mileage Thread
Post by: Jeffy on March 16, 2011, 12:07:32 AM
half throttle. i will be driving home on friday. my speedo isnt recalibrated, but i have a gps unit. ill pay closer attention to my rpms at 60-65. but i know for a sure that cruising at 65mph with my current equipment (33s, 3.73gears,3spd auto, 62mm tb, CAI, header/exhaust/hi-flo cat) i am under 3k (maybe 2750-2800) and i am around 15mpg. i will pay closer attention when i head home on friday.
Seeing as the PCM uses the VSS (aka: speedometer) to adjust timing as well as the air/fuel, you are probably losing some points there.
Title: Re: Gas Mileage Thread
Post by: sharpxmen on March 16, 2011, 07:54:33 AM
half throttle. i will be driving home on friday. my speedo isnt recalibrated, but i have a gps unit. ill pay closer attention to my rpms at 60-65. but i know for a sure that cruising at 65mph with my current equipment (33s, 3.73gears,3spd auto, 62mm tb, CAI, header/exhaust/hi-flo cat) i am under 3k (maybe 2750-2800) and i am around 15mpg. i will pay closer attention when i head home on friday.

how do you calculate mpg?
Title: Re: Gas Mileage Thread
Post by: stan98tj on March 16, 2011, 11:09:21 PM
how do you calculate mpg?
it was a rough calc. from fill up to nearly empty. i know it's not the most accurate way to calculate it, but it gives me a rough estimate. sometimes ill calc it to half tank as a rough look.
Title: Re: Gas Mileage Thread
Post by: Jeffy on March 16, 2011, 11:23:39 PM
it was a rough calc. from fill up to nearly empty. i know it's not the most accurate way to calculate it, but it gives me a rough estimate. sometimes ill calc it to half tank as a rough look.
How'd you calculate your mileage then?  With the speedo off your odometer will also be off.
Title: Re: Gas Mileage Thread
Post by: sharpxmen on March 16, 2011, 11:51:15 PM
it was a rough calc. from fill up to nearly empty. i know it's not the most accurate way to calculate it, but it gives me a rough estimate. sometimes ill calc it to half tank as a rough look.

that's not the way to do it though, you fill up, drive about 200 miles then fill up again, divide the miles between fill-ups to the gallons you put in the last fillup and you get your mpg. Otherwise you don't know if you have 1 or 3 gallons left in the tank and that can be the difference you're looking for (like 15 to 18 mpg for that 2 gallon difference). 1/2 tank is even more inaccurate as the sender is very loose in indication.
Title: Re: Gas Mileage Thread
Post by: stan98tj on March 17, 2011, 02:55:18 PM
How'd you calculate your mileage then?  With the speedo off your odometer will also be off.
used my gps for milage
Title: Re: Gas Mileage Thread
Post by: sharpxmen on March 17, 2011, 04:31:40 PM
used my gps for milage

that is also not accurate (unless the road you drive is a perfect straight line), odometer or known distance on the hwy is the way to do it.
Title: Re: Gas Mileage Thread
Post by: Jeffy on March 17, 2011, 04:45:07 PM
used my gps for milage
I don't think a GPS is a good way to calculate your mileage.  Unless you wait for the GPS to connect, you'll get inaccurate numbers.  A GPS is also only accurate up to 15 meters as well.

What you want to do is replace the speedometer gear so it's within 1-2MPH.  Then fill up and drive till you need to fill up again.  Do this a few times and make sure you don't top off.  This will give you more accurate numbers.  Then if you want to get anal about it, get something like the OBD-II ScanGauge II which can give you real time mileage.  This is the one feature I wish my Jeep had.
Title: Re: Gas Mileage Thread
Post by: sharpxmen on March 17, 2011, 05:29:58 PM
I don't think a GPS is a good way to calculate your mileage.  Unless you wait for the GPS to connect, you'll get inaccurate numbers.  A GPS is also only accurate up to 15 meters as well.

What you want to do is replace the speedometer gear so it's within 1-2MPH.  Then fill up and drive till you need to fill up again.  Do this a few times and make sure you don't top off.  This will give you more accurate numbers.  Then if you want to get anal about it, get something like the OBD-II ScanGauge II which can give you real time mileage.  This is the one feature I wish my Jeep had.

what do you mean by "don't top off"?
Title: Re: Gas Mileage Thread
Post by: Jeffy on March 17, 2011, 05:30:50 PM
what do you mean by "don't top off"?
Top off the tank with gas.
Title: Re: Gas Mileage Thread
Post by: brokenwrist21 on March 31, 2011, 11:15:16 PM
mileage varies wildly from about 12 to about 14.5 mpg's
ax5 manual, synchromesh fluid
amc 2.5mpfi, pennzoil platinum full synthetic oil
bfg mud terrain ta/km 33x10.50r15
4.88 synthetic rear diff lube.
spedo calibrated
4.0l tb, tb spacer, k&n drop in air filter, flowmaster muffler, high flow cat, msd 8.5mm super conducter wires, bosch iridium +4 plugs,rv cam from delta camshafts, yella terra roller rockers.
Title: Re: Gas Mileage Thread
Post by: stevenu on April 01, 2011, 05:20:02 PM
Tried out 93 octane last fill up at 3.799. pulled 18 mpg.

2.5
AX-5
31x10.5
throttle body and spacer
dynomax cat back
speedo calibrated
KnN drop in filter

Title: Re: Gas Mileage Thread
Post by: Torch_Ind on April 01, 2011, 05:44:03 PM
Tried out 93 octane last fill up at 3.799. pulled 18 mpg.

2.5
AX-5
31x10.5
throttle body and spacer
dynomax cat back
speedo calibrated
KnN drop in filter




does that make it worth paying more?
Title: Re: Gas Mileage Thread
Post by: sharpxmen on April 01, 2011, 05:50:08 PM
Tried out 93 octane last fill up at 3.799. pulled 18 mpg.

2.5
AX-5
31x10.5
throttle body and spacer
dynomax cat back
speedo calibrated
KnN drop in filter



what were you getting with regular (87)?
Title: Re: Gas Mileage Thread
Post by: stevenu on April 01, 2011, 07:04:50 PM
Last 87 octane was 16.3mpg.  It works out in my favor paying more but just barely. Please know that this is my first Jeep and my first standard, I'm still figuring the best way to get around. I know in my 4 runner it helped running a higher octane so I'm trying it out. I will post again when i fill up next with 87.
Title: Re: Gas Mileage Thread
Post by: stan98tj on April 15, 2011, 10:14:37 AM
really I get 15 with mods and 6inches of lift 4.88's and 33's with open front fenders and a bit top light bar.. I could prob squeeze 17ish if I was easy on it in nice weather and flat strait roads.

also I did a mpg check when I was stock with 31's pulling a small trailer with a min z on it. and all our gear in the jeep we got roughly 22mpg

what do you got for a build ??
also do you run a/c
let it idle a lot?
clutch fan stuck?

stock fan. no a/c. 33s 3.25" lift. 3spd auto. 62mm Tb/spacer. aem intake. banks header and catback. high flow cat.
Title: Re: Gas Mileage Thread
Post by: RockinH5 on April 27, 2011, 10:01:05 PM
Fully stock 2.5L YJ on 31x10.50 getting about 16-18mpg.
Title: Re: Gas Mileage Thread
Post by: Jeffy on May 04, 2011, 11:24:29 PM
Well, the on the last tank of gas I got 17.5 mpg.  Seems to get better mileage as I run the tank dry.  I got over 300 miles out of the tank with 1-2 gallons left.  I think the most I've dared to do was around 330 miles.  On average I've been getting 15 mpg city for the last 3-4 years.  Before that it was 16-18 with a lot of highway driving.  It will be interesting to see how it changes with the new tires.  Although my speedometer is off by a small amount.  I should still be able to get an idea of the mileage since I know how off it is.
Title: Re: Gas Mileage Thread
Post by: WranglerCOdy on May 06, 2011, 06:19:46 AM
i get horrible gas miliage right now ahah. due to 35's that are the size of bald 37's.(pulled up next to me budy with 37's and they were a little bit smaller.)

but i have in my heep

4.0throttle body
throttle body spacer
Cold(ish) air intake
Flowmaster 40 series
electric fan(big difference!!!!!)


also cleaned out my PCV and notice that the majority of my blow by is gone. 2.5 L have a type of PCV called a fixxed Orafice. it is the brass fitting on the front of the valve cover. in my case, mine was serious clogged full of dirt and oil or something and would not allow it to ventalate. and with it clogged it will squeeze oil out of everywhere. when i cleaned that bad boy in the parts washer and cleaned my Vent filter on the rear of the the valve cover i have noticed that it isnt nearly as nasty as it used to be. it was so bad it would go thru the filter and coat the fire wall and harness with oil. also noticed after cleaning it that made a noticeable gain in performance. it seemed as if it wasnt working as hard as it usually would have to previous to cleaning the PCV.

i still most likely have some blow by and i plan on actually running a catch can to keep the engie bay a little but cleaner.
Title: Re: Gas Mileage Thread
Post by: jramey on May 18, 2011, 12:42:33 PM
2.5l mpfi xj stock
Ax5
4.10
Stock wheels

I was gettn righr around 20mpg before the 4.0tb, havnt calculated since but it seems with the tb that im gettn better. Filling up tomorrow and ill recalcutate n see
Title: Re: Gas Mileage Thread
Post by: Quite Happy on May 24, 2011, 10:18:30 PM
Just shy of 9 (yes, single digit) last fill up.  I'm thinking maybe something's going on with the ECM that controls the mixture.  Maybe leaner would give me the added horsepower I'm looking for.
Title: Re: Gas Mileage Thread
Post by: Jeffy on May 24, 2011, 10:35:31 PM
Just shy of 9 (yes, single digit) last fill up.  I'm thinking maybe something's going on with the ECM that controls the mixture.  Maybe leaner would give me the added horsepower I'm looking for.
A CJ will be lower then a YJ but 9 is pretty low.  I think 12-16 would be average with 50/50 Town/Highway.
Title: Re: Gas Mileage Thread
Post by: jramey on May 27, 2011, 05:00:33 PM
Calculations after the tb swap put me at 23.3mpg, keep in mind that was mostly hwy miles
Title: Re: Gas Mileage Thread
Post by: Jeffy on May 27, 2011, 05:30:35 PM
Calculations after the tb swap put me at 23.3mpg, keep in mind that was mostly hwy miles
That's pretty good.  The XJ's are a lot more aerodynamic then the Wranglers which helps a lot.
Title: Re: Gas Mileage Thread
Post by: Eucalypta on May 28, 2011, 11:21:40 AM
13.4 MPG  with my 2.5L, 4.0L TB, 33"x12.5" Mud tires, 4.10 diff
Drove about 120 miles on highway@ 60 mph and alot of off-road wheeling so I guess this will be better when I drive it on paved roads only.


Next weekend we will be exploring Furtenau in Germany (http://www.furstenforest.eu/)
I will be burning a tank of fuel on my way to the park so I will get some more information.

BTW: we have to pay $ 8.59 for a galon petrol 95 !!!

Title: Re: Gas Mileage Thread
Post by: sharpxmen on May 28, 2011, 07:53:43 PM
why not use 90 octane, is it still available in Europe?

so is the liter of 95 at 1.58 Euro now? (based on the price you gave that's what comes to) - was about 1.15 when i was there 4 years ago.
Title: Re: Gas Mileage Thread
Post by: Eucalypta on May 31, 2011, 01:10:13 PM
why not use 90 octane, is it still available in Europe?

so is the liter of 95 at 1.58 Euro now? (based on the price you gave that's what comes to) - was about 1.15 when i was there 4 years ago.

Only Euro 95 and 98 is available.
Prices vary; most are over € 1,60 / liter
On top of this; we have to pay road taxes which are dependable on weight and environmental impact of your car.
A Wrangler costs about € 160,= for 3 months.

This is the reason many Dutch buy very small/light cars. We just ordered a Renault Twingo 1.2L; this goes 18km on a liter and is taxfree for the next 2 years....
We keep the Wrangler and the minivan, the Grand Cherokee will be sold :((((
Title: Re: Gas Mileage Thread
Post by: sharpxmen on May 31, 2011, 01:46:19 PM
Prices vary; most are over € 1,60 / liter

ouchieeee  :brick:
Title: Re: Gas Mileage Thread
Post by: jfrabat on May 31, 2011, 03:00:30 PM
Only Euro 95 and 98 is available.

For some reason, here in CR as well as Panama, only 91 and 95 octane is available...  no 87 octane gas.
Title: Re: Gas Mileage Thread
Post by: sharpxmen on May 31, 2011, 04:23:50 PM
For some reason, here in CR as well as Panama, only 91 and 95 octane is available...  no 87 octane gas.

Europe used to have 90, 92 and 98 if i recall correctly (or maybe 90 and 98). 90 was used mostly in trucks and utility vehicles, all the small cars were using 98. then the unleaded came along and 95 was born. And seems that 90 and 92 is gone based on what he said. Diesel was always around, and used to be way cheaper than gasoline, last time i was there it was little difference in price (still cheaper but not by much). There was one kind of diesel (can't remember the name) which apparently was cleaner and more powerful (what the guy said at the pump trying to make me use that instead of good 'ol diesel fuel) and I think it was more expensive than the 95 octane. Funny thing is that you could buy heating oil for housing which was less than 1/2 the price (that was due to less taxes since it was for heating so not automotive use) and worked just fine in a diesel, but there was a limit as to how much you can use/buy every month based on house footprint or square footage to be more exact, there was still some room left to order some extra for a diesel vehicle.

EDIT: or maybe it was 90, 94 and 98 - can't remember
Title: Re: Gas Mileage Thread
Post by: Jeffy on May 31, 2011, 04:50:51 PM
For some reason, here in CR as well as Panama, only 91 and 95 octane is available...  no 87 octane gas.
There's really no reason for so many grades anyway.  It's cheaper to produce fewer grades.  I bet it's because most old pre-unleaded cars don't like 87.  There's no reason to make it other then to have a wider spread between prices.
Title: Re: Gas Mileage Thread
Post by: Eucalypta on June 01, 2011, 03:40:19 AM
Indeed we used to have more grades but only the 95 and 98 are left and even the 98 less and less available.

In France 95 is mixed with 5-10% bio fuell which some think are bad for you engine. In The Netherlands we will get 5% mix within a few years.

Diesel is very good available here and is about 1,43 Euro/liter. Cheaper as gasoline but the roadtax is much higher. So if you drive many miles/year, diesel is the best choice.
You can buy "red" diesel, which is used for agricultural vehicles and indeed some (older) homes use as heating fuell (although I do not any becasue we have a nationwide network of undergroud natural gas pipelines). This is the very same diesel as you put in the normal cars and trucks however, without the added fuell taxes. Thus it is illegal to use it in your car.

You can also make your own biodiesel by using sunflower oil; per liter very cheap and also very environmental friendly but....because there is no fuelltax on it...illegal to use.

We have a lot "LPG" Liquified Petroleum Gas stations. This is the least expensive fuell you can get; about 0,80/liter. Again; roadtax is much higher for these vehicles plus you will have to invest in your car by installing a LPG installation and tank. This makes it only interesting if you really eat miles and miles.

We see ALOT of "premium" gasolines and diesels in Europe. Every brand has its own.
It is said that it "cleans" the engine, increases performance and saves fuell.
It comes for 95 and diesel
I tried the Premium diesel for 6 months, 30.000 km and found absolutely no difference with the normal diesel.
Title: Re: Gas Mileage Thread
Post by: Jeffy on June 11, 2011, 06:53:28 PM
Well the first tank through the Jeep with the calibrated speedometer and new tires yielded 16.5MPG.  Although, I filled up with 5-7 gallons still in the tank.  The Jeep usually gets it's best mileage when the tank is almost empty so I suspect it's a bit better.  That's all city driving and mostly 6 mile trips which really isn't good for mileage.  Didn't bother trying to baby it like I would normally have to to get that sort of mileage with the old tires.  Maybe I'll try babying it and see where it goes.
Title: Re: Gas Mileage Thread
Post by: grumpygy on June 22, 2011, 06:42:16 PM
1st real tank thru it after getting it back running.  Today 15.5 MPG.  If I did my math right  Speedo is off by 5Mph 60=65.  So My Milage was 188 Converted is 203.  filled 13.137 Gal.


•Transmision Type (ie., Automatic - 30RH/TF909, AW4 etc..., Manual - AX-4, AX-5, AX-15, NV1500, NV3550, etc...)
 Believe AX5
•Engine Type (ie., F134, L134, Pontiac 151, AMC 150 Carburetor, AMC 2.5L TBI, AMC 2.5L MPFI, Chrysler 2.4L, etc...)
2.5 MPFI
•Tire Size
31/10.5
•Differential Gearing (ie., 3.73:1, 4.10, etc...)

Stock 4.11
•Speedometer Calibration (ie., Y/N)
No
•List of ENGINE Mods if any

4.0 Throttle Body, throttle Body Spacer, 19 LB injector, Cat is Gone and good free flow Muffler and a cold air intake.







Title: Re: Gas Mileage Thread
Post by: Torch_Ind on June 22, 2011, 07:03:33 PM
1st real tank thru it after getting it back running.  Today 15.5 MPG.  If I did my math right  Speedo is off by 5Mph 60=65.  So My Milage was 188 Converted is 203.  filled 13.137 Gal.


•Transmision Type (ie., Automatic - 30RH/TF909, AW4 etc..., Manual - AX-4, AX-5, AX-15, NV1500, NV3550, etc...)
 Believe AX5
•Engine Type (ie., F134, L134, Pontiac 151, AMC 150 Carburetor, AMC 2.5L TBI, AMC 2.5L MPFI, Chrysler 2.4L, etc...)
2.5 MPFI
•Tire Size
31/10.5
•Differential Gearing (ie., 3.73:1, 4.10, etc...)

Stock 4.11
•Speedometer Calibration (ie., Y/N)
No
•List of ENGINE Mods if any

4.0 Throttle Body, throttle Body Spacer, 19 LB injector, Cat is Gone and good free flow Muffler and a cold air intake.

around the 15mpg is about average you could prob drive it more old man like and get a bit better but that's about the norm
Title: Re: Gas Mileage Thread
Post by: road2damascus on June 23, 2011, 07:07:43 AM
My last 5 tanks were 16.8, 17.8, 18.1, 17.9, and 17.5. I have 30-9.5-15 BFG A/T's. How do you "convert" with slightly larger tires and would there be any difference with 30's?
Title: Re: Gas Mileage Thread
Post by: Jeffy on June 23, 2011, 09:11:11 AM
My last 5 tanks were 16.8, 17.8, 18.1, 17.9, and 17.5. I have 30-9.5-15 BFG A/T's. How do you "convert" with slightly larger tires and would there be any difference with 30's?
Yes, as stock tires are usually 205.75R15's or 215.75R15's  There was also an option for 225.75R15's.  If you haven't adjusted your speedometer then you're mileage will read lower then it actually is.  If you look at the door tag it will tell you what size tires it came with.
Title: Re: Gas Mileage Thread
Post by: Torch_Ind on June 23, 2011, 04:31:28 PM
My last 5 tanks were 16.8, 17.8, 18.1, 17.9, and 17.5. I have 30-9.5-15 BFG A/T's. How do you "convert" with slightly larger tires and would there be any difference with 30's?

was this all the same daily driving or is every tank typically different locations?

I just ask as to why you hit a 18mpg spike. I would like to know what was different for that tank of fuel..

and 15mpg is typically once your over 31's for tires average in town and highway mix driving.. you could get better if you did lots of highway and drafting/ following traffic.  

I used to get over 20mpg's highway in bone stock form.
Title: Re: Gas Mileage Thread
Post by: grumpygy on June 23, 2011, 06:12:44 PM
around the 15mpg is about average you could prob drive it more old man like and get a bit better but that's about the norm

But I am An old Man and want to drive younger. :blbl:
Title: Re: Gas Mileage Thread
Post by: road2damascus on June 23, 2011, 08:04:58 PM
was this all the same daily driving or is every tank typically different locations?

I just ask as to why you hit a 18mpg spike. I would like to know what was different for that tank of fuel..

and 15mpg is typically once your over 31's for tires average in town and highway mix driving.. you could get better if you did lots of highway and drafting/ following traffic. 

I used to get over 20mpg's highway in bone stock form.

I think the 18.1 was more highway (55mph in fifth right in between 2000-2500rpms). Yes it was all daily driving.
 
Yes, as stock tires are usually 205.75R15's or 215.75R15's  There was also an option for 225.75R15's.  If you haven't adjusted your speedometer then you're mileage will read lower then it actually is.  If you look at the door tag it will tell you what size tires it came with.

So with 30 inch tires I am getting more MPG than what I am calculating.

Title: Re: Gas Mileage Thread
Post by: Jeffy on June 23, 2011, 08:39:54 PM
So with 30 inch tires I am getting more MPG than what I am calculating.
Yes.
Title: Re: Gas Mileage Thread
Post by: sharpxmen on June 23, 2011, 09:09:07 PM

So with 30 inch tires I am getting more MPG than what I am calculating.


easy to calculate

real_mpg=calculated_mpg*(new_tire_diam/old_tire_diam)

so if you had 28 and now you're on 30 and you calculated your mpg to be 15 your real one was actually 15*30/28=15*1.07=16

so you're 7% off on both miles at the odometer, mph on the speedo and mpg.

of course this is all based on what stock tires the Jeep had on.
Title: Re: Gas Mileage Thread
Post by: road2damascus on June 23, 2011, 09:22:05 PM
I don't have the original doors. Its a Wrangler "S" and so was the guy I traded doors with. 205-75-15.
Title: Re: Gas Mileage Thread
Post by: Jeffy on June 23, 2011, 10:30:05 PM
I don't have the original doors. Its a Wrangler "S" and so was the guy I traded doors with. 205-75-15.
So he has your VIN barcode as well.

Stock for ths S are 205.7515's.  Those were usually mounted to the 9-slot 15x6 wheels.  If you have the 5-spoke wheels then you probably has 215.75R15's.  I can't see what you have on the Jeep.
Title: Re: Gas Mileage Thread
Post by: road2damascus on June 24, 2011, 06:41:21 AM
I had the 9 slot steel wheels. They were 15x6. Now American racing.
Title: Re: Gas Mileage Thread
Post by: Torch_Ind on June 24, 2011, 06:45:43 PM
But I am An old Man and want to drive younger. :blbl:


:thumb:

ya I hear ya! you don't buy jeeps for mpgs is my opinion lol.
Title: Re: Gas Mileage Thread
Post by: chrisfranklin on June 28, 2011, 01:56:27 PM
Getting gas today, I worked out mpg.    272 miles  / 17.5 gallons = 15.54 mpg. 

Got this after doing mixed city/highway (65-75mph) driving since last fill-up.  This is on 31s/4:10s, speedometer gear corrected. 

It's about what I expected it was getting -- was figuring 14-15mpg city, 16-17mph highway

Have been using the mean green starter I've got on there more lately.  If I know I am going to be idling for 2-3 minutes at a familiar traffic light, I kill the engine (course, everybody thinks I've run out of gas when they hear it crank when the light is getting ready to turn  :wall:)
Title: Re: Gas Mileage Thread
Post by: Torch_Ind on June 28, 2011, 06:41:21 PM
Have been using the mean green starter I've got on there more lately.  If I know I am going to be idling for 2-3 minutes at a familiar traffic light, I kill the engine (course, everybody thinks I've run out of gas when they hear it crank when the light is getting ready to turn  :wall:)

 :roflol: that's awesome!!
Title: Re: Gas Mileage Thread
Post by: chardrc on July 08, 2011, 04:21:19 PM
went through the first full tank of gas on road in my jeep since I've owned it. got 17.3mpg   :weee:... a nice surprise to me since I wasn't easy on the throttle given that 1/4 of the way through the tank i installed the new tb and had to test it out  :driving:. and before the new tb i was basically to the floor to keep up with traffic... but it was mainly highway miles... better than the 13 I used to get when this thread started.
Title: Re: Gas Mileage Thread
Post by: Jeffy on July 08, 2011, 04:22:23 PM
went through the first full tank of gas on road in my jeep since I've owned it. got 17.3mpg   :weee:... a nice surprise to me since I wasn't easy on the throttle given that 1/4 of the way through the tank i installed the new tb and had to test it out  :driving:. and before the new tb i was basically to the floor to keep up with traffic... but it was mainly highway miles... better than the 13 I used to get when this thread started.
Is that with just the new TB?
Title: Re: Gas Mileage Thread
Post by: chardrc on July 08, 2011, 05:06:37 PM
its a combo of three things.
1 the correct spark plugs (old owner had chevy v8 plugs in ti which are totally wrong).
2 electric fan
3. 50mm tb. changed after the first 35 miles on the tank (200 miles total before fill up I don't trust the gas gauge on the low end)
4. iirc that 13mpg tank was mainly city driving.

edit:
if the forecast looks sunny again this week i will see what kinda millage I can get when i know how fast im going... forgot how far off the speedo was and now know why i was getting to work so early... a decent chunk of improvement has to be from new tb, used to be pedal to metal most of the highway commute and now i can cruise at 3/4 throttle for a good portion of the commute.
Title: Re: Gas Mileage Thread
Post by: sharpxmen on July 08, 2011, 05:34:29 PM
its a combo of three things.
1 the correct spark plugs (old owner had chevy v8 plugs in ti which are totally wrong).
2 electric fan
3. 50mm tb. changed after the first 35 miles on the tank (200 miles total before fill up I don't trust the gas gauge on the low end)
4. iirc that 13mpg tank was mainly city driving.

edit:
if the forecast looks sunny again this week i will see what kinda millage I can get when i know how fast im going... forgot how far off the speedo was and now know why i was getting to work so early... a decent chunk of improvement has to be from new tb, used to be pedal to metal most of the highway commute and now i can cruise at 3/4 throttle for a good portion of the commute.

sh!t, wish i knew before pricing it out  :lol:
Title: Re: Gas Mileage Thread
Post by: road2damascus on July 10, 2011, 02:47:48 PM
18.08 mpg, 30" bfg AT, no correction for larger tires, NEW autolite platinum spark plugs
Title: Re: Gas Mileage Thread
Post by: chardrc on July 13, 2011, 08:47:30 PM
filled up the jeep again today. another 17mpg tank... im happy.. but my s10 apparently wasn't... :brick:
Title: Re: Gas Mileage Thread
Post by: road2damascus on July 20, 2011, 06:50:11 AM
My best yet, 18.54. Only difference from previous tanks was that I put a double dose of Lucas fuel treatment in the tank. Still not corrected for 30" tires.
Title: Re: Gas Mileage Thread
Post by: chrisfranklin on July 20, 2011, 08:18:07 AM
Was looking for a small bumper sticker saying:  

My "4" can out-"drink" your "8!"  



 :wall:
Title: Re: Gas Mileage Thread
Post by: jramey on July 23, 2011, 02:07:03 PM
Was looking for a small bumper sticker saying:  

My "4" can out-"drink" your "8!"  



 :wall:

Lol im sure you could hav that made
Title: Re: Gas Mileage Thread
Post by: Torch_Ind on July 23, 2011, 06:23:39 PM
Was looking for a small bumper sticker saying:  

My "4" can out-"drink" your "8!"  



 :wall:

 :thumb:  I would get that to.. I want to turbo mine as well lol bye bye fuel lol
Title: Re: Gas Mileage Thread
Post by: chrisfranklin on July 24, 2011, 07:16:21 PM
Maybe if I don't find anything out there, I'll get a shop to design/print some. 

What kind of graphic, if any, works with something like that blurb? Or maybe you just forget the graphic and do straight white text on black or vice versa?   I know what I like for decals/bumper stickers, but my skilz figuring what other people like has always been  :gimp:  ( :lol:)
Title: Re: Gas Mileage Thread
Post by: JeepNeek on July 28, 2011, 02:48:17 AM
My MPG using 93 octane - 17.75

Transmision Type - Manual - NSG 370
Engine Type - Chrysler 2.4L, etc...)
Tire Size - 31"
Differential Gearing - 4.10
Speedometer Calibration (N)
List of ENGINE Mods if any Jet Chip ,TBS, Magnaflow exhaust,Airad Intake.
Title: Re: Gas Mileage Thread
Post by: Jeffy on August 13, 2011, 08:32:11 PM
So after a few months ago I swapped my wheels and tires from 15x8.5 Cast aluminum wheels and 35x12.5R15 GT MT/R's with 15x7 5-spoke OEM's and 33x10.5R15 BFG KM2's.  I've run a few tanks through so here are the results.  With my old setup I was getting an average of 15MPG.  It would dip as low as 14MPG and if I tried hard I could get 16MPG.

With the new tires and wheels I'm averaging 17.5MPG without trying.  Actually, the low was 17.3MPG.  Haven't really tried to be conservative to see how much higher I can get it but I do drive rev to 4000RPM still.  I suspect that on a road trip at 65-70MPH it will be in the 20's.  But that's just speculation right now.
Title: Re: Gas Mileage Thread
Post by: FourbangerYJ on August 22, 2011, 04:54:15 PM
(http://i30.photobucket.com/albums/c331/FourbangerYJ/WestLake2011004.jpg)
I knew if I slowed down I would get better mileage. While convoying with another Jeep we averaged between 60-65 (2700-2800 RPM) miles per hour. I got 17.3 MPG loaded to the gills and climbing the Grapevine from L.A. towards Fresno. I had no idea that 500 RPM would make such a huge change. Last time I did this trip a few weeks ago I was just as loaded and averaged 11.5 MPG while doing 70+ and 3200 RPM.
Title: Re: Gas Mileage Thread
Post by: Torch_Ind on August 22, 2011, 05:08:19 PM
I knew if I slowed down I would get better mileage. While convoying with another Jeep we averaged between 60-65 (2700-2800 RPM) miles per hour. I got 17.3 MPG loaded to the gills and climbing the Grapevine from L.A. towards Fresno. I had no idea that 500 RPM would make such a huge change. Last time I did this trip a few weeks ago I was just as loaded and averaged 11.5 MPG while doing 70+ and 3200 RPM.

takes a lot to get a little

it helped to that you all drafted each other!!
Title: Re: Gas Mileage Thread
Post by: Jeffy on August 22, 2011, 05:31:02 PM
I knew if I slowed down I would get better mileage. While convoying with another Jeep we averaged between 60-65 (2700-2800 RPM) miles per hour. I got 17.3 MPG loaded to the gills and climbing the Grapevine from L.A. towards Fresno. I had no idea that 500 RPM would make such a huge change. Last time I did this trip a few weeks ago I was just as loaded and averaged 11.5 MPG while doing 70+ and 3200 RPM.
Wind resistance/aerodynamics comes into play at speeds above 35MPH and increase exponentially.  Dropping down from 70mph to 60mph makes a huge difference.  Drop down to 50-55mph and you'll see more gain.
Title: Re: Gas Mileage Thread
Post by: road2damascus on August 23, 2011, 08:13:26 AM
Wind resistance/aerodynamics comes into play at speeds above 35MPH and increase exponentially.  Dropping down from 70mph to 60mph makes a huge difference.  Drop down to 50-55mph and you'll see more gain.

I have the option of driving to work on the expressway @ 55mph (around 2500rpm in fifth) or taking side streets @ up to 45 mph (never over 2000rpm). I have tried both ways with full tanks of gas. There is a huge difference in MPG. Never getting past 2000 rpm for long distances sucks a lot less fuel. The other day I was going 70 mph @ 3500rpm and I could look down every five minutes and see the gas gauge go lower and lower.
Title: Re: Gas Mileage Thread
Post by: chardrc on August 23, 2011, 12:36:30 PM
The other day I was going 70 mph  (at)  3500rpm and I could look down every five minutes and see the gas gauge go lower and lower.

I have watched my gas gauge go down almost a quarter tank on my drive home when I go over 70mph.  :yikes:... speed definitely makes a difference. couldn't imagine going any real distance with all under 2000 rpm. my jeep doesn't come to life until 2000k (aka if you want to have a chance to maintain speed on a hill in 4th) and gets nice around 2500rpm.
Title: Re: Gas Mileage Thread
Post by: Higgs on August 23, 2011, 01:31:04 PM
couldn't imagine going any real distance with all under 2000 rpm. my jeep doesn't come to life until 2000k (aka if you want to have a chance to maintain speed on a hill in 4th) and gets nice around 2500rpm.
I could barely hold my speed at 2k and definitely could not accelerate from those rmps. Now that I have the 4.0L throttle body it at least doesn't feel boggy. I need a good flat surface to drive around 2k and certainly no less than that.
Title: Re: Gas Mileage Thread
Post by: road2damascus on August 23, 2011, 07:42:22 PM
Chicago-land is flat. I shift after 2000 rpm. On hills I down shift. With stock gears, 30" tires and modifications it does fine. Last MPG uncorrected was 17.7 uncorrected for the tires.
Title: Re: Gas Mileage Thread
Post by: reddogg on August 23, 2011, 09:04:25 PM
Just go back from a trip from Delaware to Tennessee.95 Jeep 2.5L got 21.6 mpg down and back. stock 225/15 tires. stock 410 gears.  I was getting between 16 and 18 before installing electric fan and 4.0tb.
Title: Re: Gas Mileage Thread
Post by: Torch_Ind on August 24, 2011, 03:43:41 PM
Just go back from a trip from Delaware to Tennessee.95 Jeep 2.5L got 21.6 mpg down and back. stock 225/15 tires. stock 410 gears.  I was getting between 16 and 18 before installing electric fan and 4.0tb.

nice!! shows improvement with the mild upgrades
Title: Re: Gas Mileage Thread
Post by: chuck172 on November 19, 2012, 04:44:27 PM
Very pleasantly surprised. I checked my mpg today for the first time ever. 22mpg. Didn't go over 60, new stock tires 215/75/15.
4.0, auto 3.07 rear.
Title: Re: Gas Mileage Thread
Post by: sharpxmen on November 20, 2012, 07:49:14 AM
Very pleasantly surprised. I checked my mpg today for the first time ever. 22mpg. Didn't go over 60, new stock tires 215/75/15.
4.0, auto 3.07 rear.

how did you check your mpg?
Title: Re: Gas Mileage Thread
Post by: Da_Skunk on November 20, 2012, 12:32:33 PM
Last tank was 13 mpg. I forgot to flash the computer after putting in 19lb injectors.  Stock 2.5 squirrels. Aerodynamics are shot I've got a light bar that is helping kill my mpg.
Title: Re: Gas Mileage Thread
Post by: sharpxmen on November 20, 2012, 02:26:11 PM
yeah, i'm not sure how chuck got his mpg calculated, it's not gallons/mile  :roflol:

guidelines for calculating correct mpg
 - to calculate mpg accurately top-up the tank, reset the trip or write down the odometer reading and drive a bunch, then top-up again and calculate the number of miles driven
 - pay attention on how the Jeep is positioned at the gas pump, the YJ/TJ gas tank is notorious for having differences while not level, best to average the mpg over several tanks to avoid errors.
 - use the numbers behind the decimal point (10.999 gallons is just that and not 10 gallons)
 - calculate mpg like this mpg=<miles_driven>/<gallons_including_decimal_places>

common errors when calculating mpg that result in ridiculous numbers:
 - if your tank shows 3/4 full it doesn't mean you only used 5 gallons (or whatever a 1/4 means in your case)
 - do not count the miles while it's been towed
 - if only driven on the highway with favorable wind the Jeep acts like a big sail, if you want to make it accurate drive the same distance back and re-calculate, better to average mpg over several tanks
 - doesn't count if driven down the mountain, you need to calculate both ways, same thing here - average works better
 - i'm sure there's other factors that I can't think of, feel free to contribute :lol:
 - EDIT: i remembered another one - larger tires without speedo recalibration can result in lower calculated mpg than actual, going the other way are smaller diameter tires or "longer" Ring & Pinion kits (odo/speedo showing more than actual speed/miles driven)
 - EDIT2: another one - doesn't count either if you draft a trailer, big truck or farm vehicles, it's your skill and patience and not real mpg.

if you're sure the Jeep is really good on gas then take the motor out and install it in a Smart car or a Fiat 500, it will get better mpg than the original and be as fast as a Corvette :lol:

if in doubt you can always check the published numbers, if you're off by too much might want to review the calculations http://www.fueleconomy.gov/feg/noframes/19193.shtml
Title: Re: Gas Mileage Thread
Post by: chuck172 on November 20, 2012, 06:41:37 PM
I filled up, traveled 163 miles, came back to the same station and filled again. I divided the gallons it took into  the miles I traveled. Came out to 22. I was stunned. I'll be rechecking from time to time to verify.
Title: Re: Gas Mileage Thread
Post by: sharpxmen on November 20, 2012, 08:11:23 PM
chuck, sounds like you did it the right way, if that is indeed the correct mpg you get the Wrangler platinum award for saving fuel. I'd be interested to see the next tank where you're at (as in from the last fillup since you calculated the mpg).
Title: Re: Gas Mileage Thread
Post by: Mozman68 on November 21, 2012, 03:13:11 AM
Have been checking mine after full fill ups since I changed tires a couple of months ago...getting right around 14 mpg on average...sometimes 14.5 if the wind is on my side, sometimes 13.8 at the lowest....

37" tires with 4.88 gearing....about 70 miles of highway a day, 5 days a week...bah.
Title: Re: Gas Mileage Thread
Post by: Jeffy on November 21, 2012, 11:52:58 AM
I've been getting 16-18 mpg city.  Lots and lots of short 12 mile trips.  I still don't do much of any highways on a regular basis.  I think what I have done matches the city mileage as I'm unable to predict the route before hand.  I might also need to tweak the air box a bit.  I have it setup for more top end and less bottom.  I was also doing 70-75 mph. which didn't help.
Title: Re: Gas Mileage Thread
Post by: chuck172 on November 21, 2012, 12:28:51 PM
chuck, sounds like you did it the right way, if that is indeed the correct mpg you get the Wrangler platinum award for saving fuel. I'd be interested to see the next tank where you're at (as in from the last fillup since you calculated the mpg).
I'm looking forward to the next fill too. Chances are the first calculation is high, I'd be happy with 18mpg.
Title: Re: Gas Mileage Thread
Post by: Jeffy on November 21, 2012, 01:05:33 PM
I'm looking forward to the next fill too. Chances are the first calculation is high, I'd be happy with 18mpg.
You'll want to keep tracking it for a long time.  I'm averaging 15.56 but that's averaged over 3 years and all the mods I've done over those years.
Title: Re: Gas Mileage Thread
Post by: sharpxmen on November 21, 2012, 04:46:47 PM
same here, average works better - i keep adding the quantity and do the odo difference since started and it's funny how my Jeep goes from even 12.75 to 17 mpg, it's actually all related to the long neck and lack of proper vents on the gastank, seen errors of 1/2 of gallon if not more based on which way the Jeep is pointing at the same gas station but averaging over several fillups makes it more accurate.
Title: Re: Gas Mileage Thread
Post by: Jeffy on November 21, 2012, 06:43:24 PM
same here, average works better - i keep adding the quantity and do the odo difference since started and it's funny how my Jeep goes from even 12.75 to 17 mpg, it's actually all related to the long neck and lack of proper vents on the gastank, seen errors of 1/2 of gallon if not more based on which way the Jeep is pointing at the same gas station but averaging over several fillups makes it more accurate.
Since I did the tires, I've brought up my average from 15 mpg.  I get a pretty solid 15.5-16.8 mpg City.
Title: Re: Gas Mileage Thread
Post by: aka-justin on November 22, 2012, 01:00:29 AM
The I6 in my Rubi has been getting 13-14 mpg to work on average - 23 miles mixed driving each way. If I drive it like a tractor at 45 mph, I'm getting 14.5 consistantly. Longer distances, I've seen as good as 18-19 highway, but usually involves hills and average is more around 16. Banks cat-back exhaust, AEM dry intake, ECU Programmed Hyper-Tech Stage 3, 5.13 gears, 4" lift sitting on 35"s, and keeping at or below 55 mph. Torque Android app has also helped me monitor my gallons per hour and psuedo MPG calculation.
Title: Re: Gas Mileage Thread
Post by: chuck172 on November 23, 2012, 02:42:55 AM
Low rears and big tires have to kill mpg. I have stock, 215/75/R15 with a 3.07 rear. As soon as I put on the tires, everything seemed to really smooth out. Less friction.
Title: Re: Gas Mileage Thread
Post by: sharpxmen on November 23, 2012, 08:18:58 AM
Low rears and big tires have to kill mpg. I have stock, 215/75/R15 with a 3.07 rear. As soon as I put on the tires, everything seemed to really smooth out. Less friction.

did you use to have bigger tires? what size?

btw, it's not the friction, it's the weight and wind resistance that counts the most (big tire=taller Jeep, wider tires, more tire sticking out=more frontal area) the friction part of the rolling tire is negligible - but yes, you get way better mpg with stock tires.
Title: Re: Gas Mileage Thread
Post by: Bounty Hunter on February 06, 2013, 01:52:35 AM
Low rears and big tires have to kill mpg.
Not necessarily.  Keeping the engine from lugging is very important.  I've consistently had 17+mpg with 35" tires and 5.38 gears.
Title: Re: Gas Mileage Thread
Post by: DanMarino on August 23, 2013, 04:33:26 AM
Stock I get 21-24 depending on how much highway driving I do around Baltimore/Washington.  I'd say I'm normally 22 or 23 mpg.  4 angry squirrels, 5 speed, stock tires and gearing.
Title: Re: Gas Mileage Thread
Post by: Jeffy on September 28, 2013, 12:14:52 AM
So here's an update on my Jeep.  With the A/C and driving from SF to Bakersfield on hwy 99 I made 20.6 mpg driving at the speed limit or slightly above.  From Bakersfield to Oakhurst, it was again around 20 mpg.  Then driving up hwy 41 which takes you from a few hundred ft to over 5000 ft in a short time (35mph most of the time), to the Yosemite Valley then out on 120 back to I580 I was getting around 16.6-17 mpg.  Still with the A/C on.  Well, until the pump decided not to work anymore and lock up.  But in any case, that's not too bad for a lifted Jeep running 33's and 4.56's at 70-75 mph.  I also had the rear packed with tools, water, and a lot of other things.  So, not too bad.  It was only a little bit more tiring then driving a car.
Title: Re: Gas Mileage Thread
Post by: jfrabat on October 14, 2013, 12:29:16 PM
So here's an update on my Jeep.  With the A/C and driving from SF to Bakersfield on hwy 99 I made 20.6 mpg driving at the speed limit or slightly above.  From Bakersfield to Oakhurst, it was again around 20 mpg.  Then driving up hwy 41 which takes you from a few hundred ft to over 5000 ft in a short time (35mph most of the time), to the Yosemite Valley then out on 120 back to I580 I was getting around 16.6-17 mpg.  Still with the A/C on.  Well, until the pump decided not to work anymore and lock up.  But in any case, that's not too bad for a lifted Jeep running 33's and 4.56's at 70-75 mph.  I also had the rear packed with tools, water, and a lot of other things.  So, not too bad.  It was only a little bit more tiring then driving a car.

That's actually quite good.  I am lucky to get 15 mpg out of mine!
Title: Re: Gas Mileage Thread
Post by: 95yj on January 31, 2014, 04:35:12 PM
on the hwy I am getting 18-20 doing 70mph. 2.5L with 31" tires. I do have a cracked exhaust manifold and a patched mid pipe that leaks like a sieve. Hopefully after I get that fixed i will see some better mpg
Title: Re: Gas Mileage Thread
Post by: chrisfranklin on February 02, 2014, 10:17:35 AM
Mine is still about 15mpg city/17 mpg highway with 4:10 gears and 31" MTs. 

My tires are holding up decently and it's going to be awhile before wear forces me to change them.   But if I moved up to some skinny 33s at some point, I'd probably do 4:88s and I wouldn't be surprised if my mileage numbers stayed around the same as now. 

I've been keeping the top off year around and using a cab-cover for when it's parked -- topless driving admittedly probably doesn't help with the aerodynamics. 

Title: Re: Gas Mileage Thread
Post by: sharpxmen on February 03, 2014, 10:30:39 AM
i'm between 14.5 and 15.5 if i drive normal, stepping on it gets me to 13s
Title: Re: Gas Mileage Thread
Post by: jfrabat on February 05, 2014, 06:32:25 PM
LAst time I checked, I was back to 14 mpg's, which is REALLy good for my rig (the best I have gotten out of her EVER was 15, and that was with no lift, no winch, no aftermarket bumpers and 31's!).
Title: Re: Gas Mileage Thread
Post by: Wrench on February 09, 2014, 07:39:35 PM
I have been getting around 12-13 on the highway, but I think that is due to a worn-out carb that doesnt atomize the fuel well.

'84 Cherokee 2.5, carbureted, AX5, 33" tires, 4.88 gears.
Title: Re: Gas Mileage Thread
Post by: Jeffy on February 20, 2014, 12:58:58 PM
So after after doing a 400 mile road trip, I've got some new numbers.  With a headwind and driving 70-75 mph, I get around 15 mpg.  If there is no headwind and I drive 60-65 mph I can get about 19-20 mpg.  No A/C this time.  Seeing the numbers I don't think A/C makes that much of a difference.  The real killer is the wind resistance.

 At 70-75 the Jeep gets a little sketchy in that you can feel the wind tossing the Jeep around.  Though it settles as you slow to below 70 mph.  My only real complaint is that my gas gauge doesn't always work so I'm using the trip meter to gauge how much as I have.  Problem is I usually have 4-6 gallons left in the tank when I'd rather have it closer to 2-3, about what's left when the gauge is on E.

There were two places where there were steep hills steep enough to have big rigs crawling at 40 mph, where I had to downshift into 3rd and rev it up (4K RPM) to hold 60 mph for several miles.

Title: Re: Gas Mileage Thread
Post by: jfrabat on February 20, 2014, 02:11:27 PM
I'd rather have it closer to 2-3, about what's left when the gauge is on E.

Maybe in YOUR rig...   :wall:
Title: Re: Gas Mileage Thread
Post by: motorhedfred on March 26, 2014, 10:56:46 AM
There's been some talk about hydrogen as a suppliment to gasoline on this thread and I'd like to add my 2¢. Most units are homemade as the commercial ones look the same as what you could put together from the isles og the Home Depot with a label on it. There's not much research data availible to the general public so we'll just consider this a fun experiment that might save you at the pump (or not).

One of the reasons people don't see the gains they were hoping for on fuel injected vehicles is they're not isolating the oxygen from the hydrogen. If you vent the oxygen to the atmosphere, the O2 sensors don't pick it up and therefore the ECM doesn't compensate with more fuel. Burning the hydrogen only richens the mixture as far as the O2 sensor is concerned which causes the ECM to pull fuel OUT to compensate.

While an HHO generator that can isolate the oxygen and vent it isn't as efficient because you need more space between the negative and positive sides, the difference in fuel economy should be substantial. One downside is, the hydrogen gas does displace some of the incoming atmosphere, but most onboard on demand type systems don't produce enough volume of gas to worry about that factor.....especially if you're not piping the oxygen into the intake. Water IS 1 part oxygen to 2 parts hydrogen after all !

MHF
Title: Re: Gas Mileage Thread
Post by: sharpxmen on March 26, 2014, 07:10:10 PM
you're right with the gains
but... theoretically, there's nothing wrong with pumping oxygen, you just press the gas pedal less (less need for oxygen from air) - remember that your fuel flow is related to the demand of power at a specific load, if you make power with something else then less need for gasoline+air (same thing with hybrids, the electric motor provides additional power so less need for fuel at times, or if you with going downhill - you can sustain the same speed with less gas pedal), but besides that you're right - all the on board H generators are not feasible, you replace the gasoline with some other fuel and it's not free regardless, plus it is probably negligible as far as quantity produced like you said.
Title: Re: Gas Mileage Thread
Post by: RickBrins on July 09, 2015, 12:02:20 PM
With 240,000 miles on my 95 yj, I am consistantly around the 15 to 16 mpg mark, 50/50 hwy and city.  When I bought it at 80,000 miles 13 years ago, I put the 4.0 thtl body and spacer on it, I also added a K&N to the stock air box, with the front venturi removed. I had a Borla header, then stock manifold, now pacesetter header, open cat and free flow exhaust.  I'm now running 30x9.5 BFG's no lift, but have not noticed much difference over the 215 or 225's that were on it when I bought it.

I always do my calculations based on fill up gallons and miles on the odometer.  I do get some fluctuations as the winter and summer gasses change over and depending on top on or off.

These numbers are also very close to those I used to get on my sadly missed CJ-5 with the 258 inline 6, very slightly lifted with 31 x 10.5's and a light bar.

My 2.5 is apart and headed to the machine shop preparing for a rebuild.  Any thoughts on internal changes to improve MPG will be appreciated, until it is buttoned up and back in.  :roflol:  If I go back to stock, I will be curious to see how much a fresh build helps the power and MPG, but I would be happier to make some proven changes.
Title: Re: Gas Mileage Thread
Post by: Jeffy on October 21, 2015, 02:56:04 PM
Well, I've decided to do an update.  After doing a basic tune-up on my jeep, ignition, injectors, plugs, oil change, rotated and checked tires, etc...  (I also lowered it 1.25".  Oh and took the panel off the airbox.  This made a difference by moving the torque to the 2K-3K range.)  I was able to take it on the road for an extended drive.  About 160 miles each trip.  On the first trip, yes I did the same trip twice, I got around 22-23mpg.  The second trip I drove a bit more aggressive and got 20 mpg.  I have driven this route once before many months ago and got 16 mpg.  I'll have to wait for next year to do a 600 mile road trip.
Title: Re: Gas Mileage Thread
Post by: tucked on March 30, 2016, 05:14:18 PM
13mpg is what I'm averaging... Less if trying to do highway speeds into a headwind!   

1995 Wrangler YJ
5-Speed
AMC 2.5L TBI
31x10.50x15" Mud Terrains
4.10
Speedometer Calibration - No
NO ENGINE Mods
Title: Re: Gas Mileage Thread
Post by: Jeffy on March 31, 2016, 05:19:51 PM
If you haven't recalibrated your speedometer then you're probably getting a bit better then that.  Although stock gears and 31's are a big jump from the stock 205's.
Title: Re: Gas Mileage Thread
Post by: 95 Lowbuck on March 25, 2020, 07:36:30 AM
1995 Jeep YJ Rio Grand, soft top, 174k miles
Completely stock motor, 5 speed, D44 rear, 4.88 gears.
TJ front axles. (front turning all the time)
33-10.50 BFG KO2’s.(25-30 psi)
No speedo calibration, but pretty close.
4” lift.
I get about 15 city, 17 hwy if not in the mountains.
One thing I want to comment about is the new KO2’S.
Although still a 2 ply side wall, I really like them compared
to the KM2’s I had on it.
Quieter, better riding, better mpg, and superior in any snow condition.
Time will tell how well they work in the rocks,
but aired down with the extra siping, and aggressive side wall tread,
I think they will do well.