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MPG test run

Discussion in 'Early CJ5 and CJ6 Tech' started by davistroy, Apr 2, 2014.

  1. Apr 2, 2014
    davistroy

    davistroy Grasshopper

    Marietta, GA
    Joined:
    Jul 30, 2009
    Messages:
    432
    Filled her up, ran downtown and back in mixed driving ... 32 miles per google maps ... Filled up again at the same exact pump. 1.713 gallons ... 18.68 MPG!!

    Does that sound right for a 66 CJ5?V6? Was better than I expected.
     
  2. Apr 2, 2014
    piffey263

    piffey263 Active Member

    Medford, OR
    Joined:
    Oct 16, 2008
    Messages:
    1,214
    Assuming all speeds were below 55 I think it's possible with a good running v6


    Last time I checked I got 14 but that was 2wd and fire roads


    Sent from my iPhone using Tapatalk
     
  3. Apr 2, 2014
    jeep2003

    jeep2003 Well-Known Member

    Upstate NY
    Joined:
    May 30, 2006
    Messages:
    1,933
    thats pretty good . Im not real good at figuring my milege but last time i think i got about 15 . What id like to do is fit an electric or even a gas motor to the pto output. like a hybrid lol maybe a golf cart motor and another alternator or two to charge the batteries. except it would only be like its working in 3rd gear. not much room under the jeep to work with either. maybe ill just stick to turning the jeep off and coasting downhills
     
  4. Apr 2, 2014
    Daryl

    Daryl Sponsor

    Bonney Lake, WA
    Joined:
    May 25, 2006
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    2,882
    I had a 71 with a 390 holley model 8007 carb on it's 225 and 3.73 gears with a T98 that got 18 pretty easy. The wife's Jeep same running gear with an auto trans only gets 10.
     
  5. Apr 2, 2014
    68BuickV6

    68BuickV6 Well-Known Member

    Hesperia, CA.
    Joined:
    Mar 12, 2012
    Messages:
    2,161
    I get 12 on a poorly tuned barely timed v6.
     
  6. Apr 2, 2014
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
    Joined:
    Aug 3, 2003
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    9,832
    18 mpg is way better than my 2.5L YJ. So much for progress.
     
  7. Apr 2, 2014
    davistroy

    davistroy Grasshopper

    Marietta, GA
    Joined:
    Jul 30, 2009
    Messages:
    432
    I was expecting 12-15, so was pleasantly surprised. Pretty small sample ... Hard to test when you have no odo ...
     
  8. Apr 2, 2014
    uncamonkey

    uncamonkey Member

    Greeley CO
    Joined:
    Jun 2, 2009
    Messages:
    2,104
    My 69 Commando V6 will get 17 MPG doing combined miles (3.73 gears)
    My 3B, V6, 5.38's with OD only gets about 15 MPG.
    The Commando has a bit over 80 K on it. The 3B motor is at about 186 K. The mileage on the motors could be part of the diffference in gas useage.
    If it's a 25% OD on the 3B, the final drive ratio is 4.04 or so, it explains some of this.
     
    Last edited: Apr 3, 2014
  9. Apr 3, 2014
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
    Messages:
    5,659
    x2 - but continued work on tuning and timing may have finally gotten mine to 14 based on a small 2 tank sample! With a 10 gallon tank, every mpg is needed.
     
  10. Apr 3, 2014
    davistroy

    davistroy Grasshopper

    Marietta, GA
    Joined:
    Jul 30, 2009
    Messages:
    432
    By the way, t86, no OD, 3.73 in the axles.
     
  11. Apr 3, 2014
    Middlefork Miner

    Middlefork Miner Member

    N. Highlands Ca
    Joined:
    Apr 1, 2013
    Messages:
    187
    My speedo is off because of my tire size, but I get VERY good mileage when I pop it into overdrive & get on the highway. 373 gearing.
     
  12. Apr 3, 2014
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Aug 3, 2003
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    "My speedo is off because of my tire size"

    Try a GPS unit.
     
  13. Apr 3, 2014
    davistroy

    davistroy Grasshopper

    Marietta, GA
    Joined:
    Jul 30, 2009
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    432
    I have a speedhut gps speedo on order ... Will post when I get it installed.
     
  14. Apr 3, 2014
    JCHansen

    JCHansen New Member

    Arizona
    Joined:
    Oct 14, 2013
    Messages:
    14
    I got 19.5 MPG on my 58 CJ5 with its kinda tired F-head (100 - 105 PSI compression with fresh rings ... yay?) driving the 5.38 axles and 31.7" tires (and the rear is welded to boot.) That was a 50/50 blend of city/highway driving and a 500 ft elevation change (down, and then back up.) I tracked it using my cellphone's GPS.

    I was pretty floored. :shock: Once I get the transmission and transfer case rebuilt and install the Warn OD that's sitting on my workbench ... I actually think I could improve that by quite a bit.
     
  15. Apr 3, 2014
    Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Virginia Beach, VA
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    Apr 28, 2011
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    5,421
    Ok here's my input on this subject my 71 has only average 12MPG. V6 +3:73 . been that way since I bought it . they weren't too worried about MPG back then . 4WD vehicle , now just as a comparison . I have a 88 ford ranger 4X4 with a 4speed auto 3:73 . 2.9 FI . and that's average is 14 MPG . factory shows the average to be 14-18 . and I mostly drive it around town . :D
     
  16. Apr 3, 2014
    noahlon

    noahlon Old Fart

    Pine Ridge, AR
    Joined:
    Dec 22, 2010
    Messages:
    206
    MPG? When it need's go juice, I fill it up. If ya worry 'bout MPG, ya don't need ta be drivin' ah JEEP!
     
  17. Apr 3, 2014
    Danefraz

    Danefraz Well-Known Member 2023 Sponsor 2022 Sponsor

    Chico CA
    Joined:
    Aug 11, 2012
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    2,277
    My '69 CJ5 w/ 225 v6 / 4.88's in it's current state gets the best mileage of any of my vehicles.

    Of course, it doesn't run, motor is in the shed, transmission and transfer case in garage;

    so it's either pushed, towed or pulled on a trailer - so it uses NO fuel...

    :p
     
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