Dropping in a new setup this week, purchased off a friend's car. Consisting of the following:

Large Street ported Motor stock intake manifolds
HKS T04S w/ ported exhaust manifold and 44mm WG
1680cc secondaries/850cc primarys, KG rail for secondaries
HKS Twin Power
Blitz FMIC
Walbro 400LPH Pump
AEM EMS Standalone


Currently the setup made 405rwhp at 13-14psi on 93 octane.

I wish to make around 500-550RWHP.

I've contemplated E85, but I don't drive the car frequently and do not want to deal with injector corrosion, not to mention the terrible loss of gas milage.

This leaves me with Water injection to support higher boost levels.

From what I've been reading, it seems that if I add Water Injection and shoot for 20psi I should max out the efficiency of this turbo around 450-475hp.

So, what can I do to take me to 500+?

I was thinking of selling the HKS turbo, keeping the t4 manifold and going up to a BW S366. Seems like a good midrange punch turbo that should easily flow 500+.

Does this setup sound reasonable if I swap to a larger turbo and retune on AI? Or am I going to need 2,000cc ID's?

 

You should be fine on the injector combo. S366 will easily make 500rwhp @ 20psi.

 

Thats what i was thinking, in no way possible do i have first hand knowledge (yet), but by the sounds of it you have a very good setup to get what you are after, there are some mods that are required in addition, i assume they have been done.