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What's your mpg?

Discussion in 'Intermediate CJ-5/6/7/8' started by bigjohn, May 10, 2011.

  1. bigjohn

    bigjohn Active Member

    Well, the gas gauge does not work (would help to hook it up) so I was testing out the mileage on my freshly road worthy jeep and made it 170 miles on 15 gallons. About half of those miles were running rich before I rebuilt the carb and got the timing right.Also, probably an hour or more running in the garage testing the temp, checking for leaks and tuning.

    So the question is, what is your mileage and is 11mph somewhat close to what I should be getting?

    Some specs include 258, t14, 33 nearly bald bfg muds, 3.73, yf one barrel, stockish exhaust, hei. I am thinking of advancing the timing, leaning it out a bit and changing to higher grade fuel.

    Thanks in advance guys.
     
  2. bigjohn

    bigjohn Active Member

    Oh, 120 miles were at 55 on the freeway and the rest were in town.
     
  3. 73cj5

    73cj5 Member

    On the highway I get 12 @ 75mph , 16 @ 55mph and 14mpg around town.
     
  4. 78-5r

    78-5r Member

    My '78 5 with 304/t-150/3.55's and 31's averages 12. I've seen a best of 15 and I still don't know how I got it...I've never been able to again. I ran mine out of gas on purpose as (my gas gauge) is not working either and it went 160 miles and took a little over 13 gallons to fill it back up. I think I have some nasties in the bottom of my tank. It runs rich for sure and I am not familiar enough with carbs yet to get it any better (been scared to try) so I've just been living with the mileage. I just go 100 mjles and fill it up to be safe...take 7-9 gallons for each 100 miles I drive.
     
  5. hudsonhawk

    hudsonhawk Well-Known Member

    When I had mine, it I got about 14 on the highway and 11~12 or so in town. It was nowhere near stock and ran EFI so it is probalby not a valid comparison. I ran a 258/T-18/4.56's and 35's. With the cage and armour it weighed in at 3750 lbs with me and my trail gear ready for a weekend. I also was not ginger with it either. I could wheel for a weekend on a tank of gas. (15 gallon fuel cell).
     
  6. sterlclan

    sterlclan Member 2024 Sponsor 2022 Sponsor

    232 3 speed glass tub average 18 or so but i dont do highway speeds
     
  7. DREDnot

    DREDnot Not new to JEEPS

    Mine got 14.2 the last time I checked. Daily driving to work mostly. Mainly 45-50 mph surface streets.
    I'm safe with 150 miles and about 4 gallon reserve.
    It would probably make it 200 miles on fumes if I kept it at a steady 50.
     
  8. bigjohn

    bigjohn Active Member

    Great, thanks for the responses guys! Ill keep working on testing and tuning to see what works. Ultimately as I work issues out here and there Im shooting for this to be my gas saver until I rebuild the vw motor and get that together. If I can get 16-18 highway then Ill be a happy camper. 14 will work though.

    Ive read on some other forums that some guys are getting 20+ mpg with theirs, but I wonder if thats with better quality or higher grade fuel than the west coast or if they are just blowing smoke...
     
  9. nwedgar

    nwedgar Now with TBI!

    I vote smoke.
     
  10. sparky

    sparky Sandgroper Staff Member Founder

    Rule number one of owning a classic Jeep is you don't discuss it's fuel economy.

    Rule number two of owning a classic Jeep is you don't discuss rule number one.
     
  11. mb82

    mb82 I feel great!

    :rofl:
     
  12. bkd

    bkd Moderator Supreme Staff Member 2022 Sponsor

    Yup

    Sent from my DROID2 using Tapatalk
     
  13. 0IIII0

    0IIII0 Nibblin' on sponge cake..

    304, T-18a, 3.73, 31 10.50 BFG, single pipe stock - 15-16 @ 65-70 flat. 12-14 mountains.
     
  14. Corveeper

    Corveeper Member

    Warmed over Corvette 327, SM420 transmission, 4.27 gears and 33” tires.
    As long as I can take back roads and keep my speed below about 50-55 MPH I can get a good 15 MPG out of it but as soon as I hit the highway and have to run 65-70 that starts dropping fast.
     
  15. 72_CJ5_MUD

    72_CJ5_MUD Gunner

    Excellent Sparky... well stated!, thank you,

    In fact... am heading back into garage and beneath my "cantankerous" 39 year-young friend.. :coffee:
     
  16. '74Renegade

    '74Renegade Active Member

    My guess is that most people are just estimating the mpg. Breaking out the calculator drastically decreases your mileage.


    So with the calculator I am getting about 15 @ 65 with a 2 barrel 304, T-18, 3.73 and 33x12.50 BFG MT's. I've never checked around town because I really don't want to know.

    You don't drive a jeep for the fuel economy.
     
  17. bigjohn

    bigjohn Active Member

    If I can get the Jeep over 12-14mpg then the Jeep officially becomes a gas saver compared to the Chevy and the non-op vw. This is the rational I use to continue putting money and work into it and neglecting the other projects. "I need it for fuel economy..."