A friend is looking to get an FD, but his leg left was injured in an accident so he's considering an auto trans. He also is quite tall, so no sunroof is also required which makes for a tough combination when FD shopping

Anyway, he's looking for 400 streetable rwhp. What trans options are out there? not for drag racing, but a more '2015' trans vs '1990s' trans

 

Stock trans holds 400whp, ever since we created our automatic PFC adapter.

Our auto FD has a 4:30 rear which really helps with low end acceleration.

 

Thanks for the info

How is the gearing/redline speeds with the 4 speed auto and the 4.30 final drive Chris?

 

Yeah the auto is very durable, I think a member on here pushed past 480hp on one and it did not want to die.

I also encourage a diff ratio swap as the stock auto diff gearing is pretty woeful, especially from 1st to 2nd gear. 1st is too severe for around the city driving, but the car is a slug in 2nd gear when off boost, and the auto trans ECU loves to start the car off from a standing start in 2nd A LOT...
A diff gearing change would definitely help that issue.

Its also a pretty simple wiring loom extension to take the 'Hold' button in the shifter and relocate it to the steering wheel area. Although I think you may lose the Hold button function with a Power FC fitted?

 

* the stock auto diff gearing is 3.90:1 which gives a theoretical top speed of something like 190+mph. Much too tall.

 

The added low end makes up for any loss of top speed. I will have another auto/4:30 on our dyno in the next month and I will pay attention to the rpms in certain gears and top speeds.



Using our adapter allows the PFC to be installed without loss of any shifter/hold functions.

 

I made 350whp on my auto FD before detuning it for my mom to drive (makes 300whp now). Stock transmission is perfect for 400whp imo. Never had a shifting issue of any sort! Hauls all day long!

 

It would be cool if one of the modern 6 to 8 speed trannies could be made to work. A decently powered auto FD is a fun ride once you get moving.

 

the Rx8 had a 6 speed auto, and it was actually nice to drive. i picture adapting the control system being hard. it should be close to physically bolting in