what do I need to change the engine in my wrx to an st its a my95.
Thanks

 

erm a sti engine

but that alone wont give you more power (well not much)

best thing is to tune yours, change the ecu to a apexi power fc
then pump the boost to 1.2 bar then youll have about 10bhp _ish more power than a sti.

 

the engine would be needed from the same phase of car, and to take advatage of the extra power available the ecu from the engine as well (or as STI Craig says get a different ecu like a power fc or esl chip)

 

I think the main difference between a wrx and a sti engine is the pistons, sti's have forged ones and the heads are a better design. You should be able to mod your car reliably to around 300bhp or even a bit more which is alot more than a standard sti, sti's have got a lot better base to start modding allthough i think the bootom ends are still the same.

 

And what are pistons if not one of the key elements of the bottom end?

STI's have forged pistons and a tougher crank, closed deck block on earlier models, semi-closed deck block on later models, steel head gaskets, and better valvetrain in the heads, hence the increased rev limit. The turbo is better on later STI's than the WRX, the intercooler and exhaust are upgraded, and the ECU is also much more aggressive on STI models to make the most of the more robust engine.

 

cranks are the same i think on the same version of car and early wrx have closed deck blocks as well

 

yes but i was just saying that the pistons are the main difference, big end failure seems to be just as common on sti's, correct me if im wrong.
i wasnt talking about turbo's, head gaskets, ecu.s. ect.