You make power in 2 places, 2, one is the aspiration, such as NA, Turbo, N20.
2nd is the head, and how well, much, efficient it flows. Donít forget, an engine is only an Air Pump, thatís it, and has been for over 100 years, only the technology has changed.
The Evo head is AMAZING, AMAZING, it'll flow enough air for the 9's and people are in the 10's on it. The only restriction is the cams, which do not allow too much flow up top, but certainly enough.
I trapped @ 108MPH with stock cams, stock cam duration is 254 or like that, I bumped BOTH to 272, this allows a LOT more air flow, also aids against detonation, as the exhaust has more time to let out the hot gases. If you had an EGT probe and measured the Temp before and after, it would drop after a cam install with ALL being equal otherwise. So I bumped the Timing and raised the limit to 8000 RPMS, The dyno read like 344WHP, its sick now, and pulls till you hit fuel cut.
My next mods are simple, (besides some IC piping, I seen the stockers on the dyno, they expand quite a Bit)
A clutch to hold the power properly
and a AEM EMS
That I would take over a new turbo, remember Tuning is KEY, **** everything else, I watched a Stock Turbo WRX run back to back to back 12.8's with nothing more then Boltonís and tuning and a NX N-Tercooler.
After that then I will **** around with the 50 trims, then it is all over gentleman
18G=600CFM and a "LIL" more hot
50 Trims=7-800CFM's and counting