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Hey guys, I´m starting a new project my idea is to build a Ej25 (2011 sti) with around 400-450 whp. The target is around 24lb of boost @ sea level. I´ve been doing some research and so far this is my starting list to change internals.

Forged pistons

Forged connecting rods

Billet crank

New oil pump

High pressure gas pump

Pressure regulator

New rails and injection system

Tomioka td06-20g twin scroll

I have some doubts...

Should I reduce compression ration on cylinder.

Should I change valves, and springsand retainers

Bigger camshaft


lightweight pulleys

Any other suggestions, I´d really appreciate the help.



No need for the billet crank at those power levels, and if you are not increasing the engine speed then the stock valves and springs usually do not have issues. With the EJ motors being an interference motor, you have to be careful about changing the camshaft, as you can have issues there, I would personally go with a 257 with the variable valve timing, and run the stock cams, as these will support the power levels that you are after.

Lightweight pulleys I haven't found to make much difference with regards to engine power and response, but they can be useful on an engine that spends most of it's time in the upper rev range as they allow for the connected devices to turn slower if it is an under driven pulley.

Thnaks for the response! So in resume it will just work with fored pistons, connecting rods, improving fuel system and oil system...

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