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Question: power and mpg?

Discussion in 'Early CJ5 and CJ6 Tech' started by Executioner, Sep 16, 2006.

  1. Executioner

    Executioner Member

    I've had the jeep around 2 weeks now and put a little over 100 miles on it. Today I'm planning on rebuilding the carb.
    Just wondering what is good mpg on the F head with the overdrive? it seems like I'm around 10 mpg, I realize these things were not designed for economy. Also the high speed power sucks, at 45 mph going up an off ramp it realy bogs down, and thats without od engaged.
    I can get up to 55mph but only on level highway or down hill. anykind os up ward incline she struggles. Is this typical performance? or do you think the rebuild will wake it up a bit?
    I was just expecting 55mph should be easy with the gearing.
    Ohh also what's the rpm range again? like shifting and top end?
    (I couldn't find the previous response) Thanks!
     
  2. 65CJ5

    65CJ5 Member

    Sounds pretty much like mine as far as overdrive performance goes (i.e., 55mph on level ground/downhill). I get about 17 mpg with a Solex carb on mine.

    Stan
     
  3. weedy

    weedy Member

    Mine gets between 16 - 19 mpg with the solex carb. The solex carb improved the economy by 2 mpg and corrected my rough/rich running problem. The solex carb is @ $125 and is a simple bolt on.


    The power you are getting out of the 4 cyl is about right. Mine cruises well at 45 - 50 mph but 55 - 60 is a strain. Unless off road in low they are very under powered. However, offroad and in low they will climb anything!
     
  4. Executioner

    Executioner Member

    Ok what rpm's are..like "pushing it" ? I try to shift between 2500 and 3 grand cause that feels like the engines peak power range.
    I read spec's online that peak hp is achieved at 4 grand? that seems like top end to me and close to the danger area.
    And thanks for the info.:)
     
  5. Glenn

    Glenn Kinda grumpy old man Staff Member

    You've got the right range in mind, 2500 to 3000, maybe 3200.
     
  6. PatchyCJ5

    PatchyCJ5 Toledo Steel

    This question may sound noobish... but i guess I am kinda noobish when it comes to some mechanical stuff.. but with all the talk about RPMs, how hard would it be to install a tachometer? I dont want to over-rev my baby.. whenever it gets 'legal'.

    Oh yea also, how many CJ5s came without a roll bar? Mine doesnt have one. When I bought it, it came with a full soft top, no roll bar.... Thanks!
     
  7. Executioner

    Executioner Member

    I don't have a roll bar either,it came with a steel hard top, The tach should be easy just follow wiring instructions.:)
     
  8. Missouri 71

    Missouri 71 Member

    You're right on the money.

    My '71 gets in the 17mpg range, come hell or high water with the Solex (LOVE IT!!!).

    Mine will go 60-65.....but it HAS to be because of the added tire diameter "helping".
    BUT....it loses all it's umph once it encounters a hill.
    Thus I avoid big highways like the plague and stick to two-lanes and backroads-it LOVES them.
    Add a few minutes to your trip and you'll be fine! R)

    I'm shocked that yours even TRIES to pull itself when you go into overdrive. That poor little F-Head HAS to be struggling.

    TACH: EASY installation.

    SOLEX: Here is THE least expensive Solex out there-where I got mine ($97.99 plus shipping):
    http://www.quadratec.com/products/51312_02.htm


    Best of luck and, like I said, allow a little extra time to get where you're going and the F-Head will be fine.....or do a V6 swap. :)