Topic: Gas Mileage Thread

[grumpygy]

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.

[Torch_Ind]

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

[road2damascus]

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?

[Jeffy]

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.

[Torch_Ind]

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.

[grumpygy]

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.

[road2damascus]

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.

[Jeffy]

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

Yes.

[sharpxmen]

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.

[road2damascus]

I don't have the original doors. Its a Wrangler "S" and so was the guy I traded doors with. 205-75-15.

[Jeffy]

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.

[road2damascus]

I had the 9 slot steel wheels. They were 15x6. Now American racing.

[Torch_Ind]

But I am An old Man and want to drive younger.

ya I hear ya! you don't buy jeeps for mpgs is my opinion lol.

[chrisfranklin]

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  )

[Torch_Ind]

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  )

  that's awesome!!