Topic: Gas Mileage Thread

[93yjFirstJeep]

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 

[stan98tj]

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.

[sharpxmen]

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.

[TahoeYJ]

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 

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 

[IdahoXJ]

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.

[SoPo94YJ]

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

[dwtaylorpdx]

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

[Sine Deviance]

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.

[jfrabat]

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...

[Sine Deviance]

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.

[radark1]

140 miles per tank. I have a 92 YJ, 4banger,....4.88 gears, 33" tires, stock tranny and transfer case. MILEAGE SUCKS!

[dwtaylorpdx]

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

[jfrabat]

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).

[sharpxmen]

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.

[tony_dt]

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.