I´m looking for different gearbox options right now and want something close to stock.

Have one problem right now and that´s "Primary Gear Reduction", what´s that? Maybe hard for me to translate or something but can´t find what that stands for.
Only see this on the stock gearbox, not on the other brands.

Is that a gear on the imput shaft before the other gears? Do you add this to the gear ratios?

Example:

AP1
6-speed, close-ratio
Primary Gear Reduction - 1.160
1st gear - 3.133 --- Est speed @ 9000rpm ~ 45mph
2nd gear - 2.045 --- Est speed @ 9000rpm ~ 60mph
3rd gear - 1.481 --- Est speed @ 9000rpm ~ 90mph
4th gear - 1.161 --- Est speed @ 9000rpm ~ 115mph
5th gear - 0.970 --- Est speed @ 9000rpm ~ 135mph
6th gear - 0.810 --- Est speed @ 9000rpm ~ 160mph
Reverse - 2.800

Thanks!

 

not sure if it's before or after the main gears, but it is cumulative.

So, for example, in 4th it is 1.16*1.16*4.10 = 5.50

 

its the "last" gear in the transmission.

Changing this has the same effect as changing the final drive. most transmissions dont have this.

 

Just get yourself the full blown supra tranny

 

That´s what I thought, hmmm... How do you calculate this? Add that number to each gear ratio?

Corey: I know but can´t afford it right now, want a low milage tranny and it´s crazy expensive over here.

 

I forget the breakdown, but I know the ap2 trans with the primary gear reduction simulates an equivalent 4.22 rear end ratio in the (first 4 gears only) compared to say the non primary gear reduced ap1 trans. If that helps at all.

 

just multiply the final drive by 1.16 and this should be equivalent. so a stock would be close to 4.75

 

http://www.turnzero.com/technical_re...ear_calculator

 

Thanks guys, great info! And that calculator will help, I did it the old fashion way, pen and paper.

 

Buy it for me and we all good.