Originally Posted by islandborn
So a question might be - are our pistons shared with the WRX or the STi? Or are they unique to our engine? I know, might be wrong, that the STi pistons are made differently?? As a few of us are pushing our engines into the 300+ hp and having them as DD with bursts of "kiss my a$$" moments, having built internals just becomes a CMA issue.
No, the '10~ pistons are different. As I understand it the new heads have a chamber volume similar to previous models but with dual AVCS added. They're not the same heads as the GRB EJ257 ('08~ STi).
Therefore, the dish volume has to be smaller to come up with the higher compression ratio. I don't know if anything is different.
We make jokes all the time about the stock pistons being made from only the finest chocolate. Truth is they're not bad, just very intolerant of knock. I know loads of people running past 300whp on stock internals for a long time. I'm at 2 years already myself. A mate did 2 years at 360whp before a HG went. It takes careful tuning and logging and being able to tell your MAF and MAP sensors apart.