Bbefore everyone starts flaming this thread, this post is out of curiosity. I want to know if anyone has the J's racing 5.125 final drive setup and if they have any driving video footage. I really want to see how close the gears are. Thanks in advance!

 

Don't have any videos or personal experience but do you have an AP1 or and AP2?
Look up videos of 4.77's. It will be a good bit shorter than that. 1st gear would be useless to use since so short. So could be nice if just starting in 2nd gear. Highway pulls the car will be slower. Even with the 4.77's it felt slower on highway pulls to me on my AP1.

 

i have an AP2. I'm familiar with the 4.77. I'm not looking to do this mod, I just wanted to see actual footage of this gearing in action. Besides, even if I did want to purchase this, it's hard to find and twice the cost of the 4.77 FD

 

5.1? WTF That is insane unless the car revs to like 13k lol

Is that ratio for a k series car?

 

i think that it either came that way on the k20 so the rsx. not sure about the new si.

 

It is a Mazda gear used in racing. I have installed 4.88 but never a 5.13...The person reported back to me it was a very fast shift but still a hoot to drive.

Good luck with your search you may want to look up Miata videos it will give you a ball park idea of the performance

 

 

topfuel on the boards has the J's 5.1 gears in his ap1.

 

I'm pretty sure he also has an AP2 transmission, which already has shorter gearing than AP1

 

overkill...