Gears And Gas Mileage

Discussion in 'Fox 5.0 Mustang Tech' started by sen2two, Aug 2, 2013.


  1. sen2two

    sen2two Active Member

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    i have 3.08 gears in my car currently and average 19--20mpg. if i go with 3.73's, what kind of change should i expect from those who have done this already?

    i do about 65% street and the rest is higway mainly around 60-70mph average.
  2. mikestang63

    mikestang63 Mustang Master

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    It all depends on how heavy your right foot is but could be about 1-2 mpg less. At highway speed you will be about 2-300 more rpm with the 3.73's. No one goes to lower gears looking for better MPG.
    f8tlfiveo likes this.


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  3. stykthyn

    stykthyn Commander of the snuggie cultists

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    city driving should see an increase but you will lose hwy mpg. 3.73s arent that tall of a gear. not sure on the rest of your combo but I would think 15-city and 22-24 hwy if everything is in good working order.
  4. Gearbanger 101

    Gearbanger 101 we love us some gays up here Super Mod

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    Won't see much if any (unless you're hard on the throttle) around town. You'll probably take. 2-3mpg hit on the highway.
  5. reldla1996

    reldla1996 Member

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    My experience has been, on two different Mustangs, that in town mileage stayed the same, but highway mileage went down 4-5 mpg.
  6. f8tlfiveo

    f8tlfiveo My wife likes my spool and blow-off valve.

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    Mpg will go down but rpm will go up faster..gears are a great way to put some pep in a fox
  7. sen2two

    sen2two Active Member

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    cool thanks. im not to comcerned about milage. but it does have a minor effect on my choices.
  8. TOOLOW91

    TOOLOW91 Mustang Master

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    I have 3.55 went from 2.73 and the loss was negligible and it woke the car up big time and still gets 20-22 at 70 on the highway


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  9. 2000xp8

    2000xp8 Mustang Master

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    Me personally i feel the difference is minimal, not enough to worry about from the gears themselves.

    Your driving is going to be the real problem, 3.08 to 3.73 multiplies the fun factor, your lack of restraint is going to cost you quite a bit of gas and you will be going through rear tires twice as fast.
    88LX5.Oh likes this.
  10. Bullitt95

    Bullitt95 Active Member

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    Going from 2.73's to 3.73's didn't change my Stang's gas mileage (city & highway) at all.

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