Been doing some math on a gear ratio calculator. Looks as though switching from 3.73 to 3.42 might be the most viable swap.
My engine makes max torque at around 2800 RPM (only 130 ftlbs). I don't think going taller in the rearend will hurt me much here because I'm still putting out just shy of 110 ftlbs at 2,000 rpms. (Ignore red line)
5th gear is a generous .83 to 1 on these puppies, and 4th is 1:1.
3.73 rear end (what I currently have). If you look at speed in 5th gear:
2000 rpm pretty well represents most gravel driving I do now
2250 rpm represents most 2 lane highway driving I do now
2500 rpm is 68 mph, usually about all should I do on the interstate…she does poorly mpg wise above this
Hypothetical 3.42 rear end swap. It seems to me that I could reasonable drop about 250 rpm’s off my cruising speed. If I’m pulling my small trailer, I can just stay in 4th gear and maintain the same mileage/economy I was getting with 3.73's.
I’m having trouble seeing a reason why I shouldn’t do the swap. I know I’ll give some up on the bottom end, but I usually pull a pretty light trailer. Turbo and intercooler are sitting on a shelf in my garage if I have any trouble getting up to speed with the new gears
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Any thoughts/input?