7thlighter
Well-Known Member
- Joined
- Nov 23, 2018
- Threads
- 3
- Messages
- 51
- Reaction score
- 23
- Location
- Northern California
- First Name
- Andrew
- Vehicle(s)
- 2019 Bullitt
- Vehicle Showcase
- 1
Thanks for taking the time to make those calculations. I was wondering about changing the gears and what that would do. What do you think it would do to the MPG?Update....I've called 3 Ford dealers over the past few weeks asking for an installation cost of the 4.09's. All of them said they'd check and let me know but none called back. I wonder if it's just bad luck or if they don't want to do this for some reason?
Also, did some calculations... 7000 rpm in my 3.73 car in 1st is 47 mph, with 4.09's it would be 43 mph. In 2nd it's 73 mph vs 66 mph, and in 3rd it's 108 mph vs 98 mph. So in terms of both 0-60 and 1/4 mile, you wouldn't have to add an extra shift if you went to 4.09's. Also, at peak 420 lb-ft of torque at 4600 rpm, the force applied to each tire patch would increase from about 2200 lbs to 2400 lbs, which would be the equivalent of increasing the peak torque from 420 to about 460. So the 4.09's seem like a pretty good mod if it's reasonably priced.
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