TR6060 Final drive Ratio

[xr4x4ti]

I posted this in my build thread:

https://www.mustang6g.com/forums/threads/awd-2017-mustang-gt-conversion.170460/page-9#post-3690036

But I didn't get much feedback and I thought I would ask the question here.

I am working on an AWD 2017 GT and I am trying to decide on Diff ratios.

I am using the TR6060 with the following gear ratios:

2.97

2.10

1.46

1.00

0.74

0.50

My car is a PP1, so it has the 3.73 Torsen rear diff.

I did some quick math and calculated total gear ratio for each gear:

To get the same total first gear ratio, I would need to go to 4.56 diff gears.

The front diff I plan on running already has 4:10 gears in it and I was planning on swapping them to 3.73's (which I already have). But, maybe it makes more sense to swap the rear to 4.10 (4.09)?

My Merkur has the 2.66 first gear T56 and it originally had 4.10 gears and it was a blast on the street. I eventually switched to 3.73's front and back so that I didn't have to shift into 5th in the 1/4 mile. But the tires are much smaller in diameter on the Merkur. The Mustang is currently running 295/35R19 tires.

	295/35R19	295/35R19	305/30/19	305/30/19
rev/mil	767	767	793	793
Redline	7500	7500	7500	7500
gear	3.73	4.1	3.73	4.1
axle rpm	2010.7	1829.3	2010.7	1829.3
4th mph	157.3	143.1	152.1	138.4

With some more math, it would suggest that I can do 143 in the 1/4 with 4.10 gears and my existing tires. The Other logical tire size is a 305/30R19 which drops my max speed to 138, but if I rev it to 7800 I am back up to 143MPH, more then I will ever run.

I plan to boost the car after the AWD is fully debugged. I shouldn't have a problem putting the power to the ground in street trim. I know most boosted people lower the gear ratio to try to control the traction on the street, but I shouldn't need to. The Merkur proved that to me.

Thoughts?
Tim

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[xr4x4ti]

I have decided to go for the 4.10 gears and let it rip

 

[MajHazrd]

I would be surprised if you can get 143 mph @ 7500 with trans ratio of 1:1 and rear diff of 4.10.
I have 3.73 and run 285/35/19 on the rear. In my 1:1 gear with 3.73, I'm maxing out at 143- 145 mph... I'd have to go back and look at some track day videos to be sure.

 

[MajHazrd]

I looked back at one of my posts and the math does work out. I thought my rpms were higher than 6800 at about 143 mph. Now I need a super charger to push up in to the 150s!
I have my governor set at 7500 as well.

 

[xr4x4ti]

Thanks for the response. You had me scared for a second I think the 4.11 gears are going to really wake up the car.

I see you are in Minnesota too, what track do you go to? I tend to go to Rock Falls or Grove Creek.

Thanks,
Tim

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