Evo 9 driveline for 600hp circuit fun...

[Markre]

Busy planning a 9 for a bit of track day and circuit work, max of 600hp (GT35 twin scroll), mostly 2nd, 3rd and 4 gear stuff, abusive pull aways will be kept to a minimum.

My initial plan was Exedy twin plate clutch and rear diff upgrade from AYC to the RS diff and sideshafts...

I now see that the RS diff once landed will cost me the same as a cusco diff and Driveshaft shop side shafts...
What exactly breaks in the AYC diff at 400hp odd?

would replacing it with a cusco diff and DSS side shafts sort it out sufficiently for 600hp?

I do see that cusco offer for AYC and non AYC, does the non AYC diff fit into a AYC casing for effective removal of the AYC function?

Also are there any semi cost effective options at keeping the 6sp gearbox from dying a premature death at 600hp?

anything else driveline that is critical at this fairly low power goal?

Sorry for the silly questions, fairly new to the Evo's driveline,,

Cheers,

[SicLanEvo]

if you are going to push 600hp go with a 5spd. The 6spd does not handle major power and no one builds them. As for the diff I would get something that suits what your going to use the car for. The RS diff only has the helical limited slip from what i understand and that was only the difference here between the 03 and 04 models in the u.s. The twin disc clutchs are good or even check out like a multipack from spec.

[Markre]

thanks, will start looking for a 5sp, will the stock 5sp hold 600hp safe?

What on the AYC diff actualy breaks?

[SicLanEvo]

not sure about the ayc diffs we didnt get it here. also you should have a built 5spd and built motor to safely run 600hp. check out sheptrans for good built 5 spds and diffs.