techno_brat

iTrader: (5)

Hey guys, just a quick question. I know the uk 01-05 2.0 Sti has the same 8.0-1 compression ratio as the WRX but what i'd like to know is, if i where to fit some STI pistons or a short motor from a uk newage sti with my WRX heads, will it change the compression ratio? i know the piston crowns are a different shape, but uses the same headgasket. Any help would be appreciated thanks

Jack

techno_brat

iTrader: (5)

bump- must be one of the pros or guru's out there that knows?

techno_brat

iTrader: (5)

come on guys- i really need to know

bigsinky

if the piston crowns, dish sizes, stroke length are different then this WILL affect the ratio if you use the recommended gasket size. you will need to compensate to get the correct compression ratio. ie you need to change the gasket thickness.

techno_brat

iTrader: (5)

hi bigsinky, i know the pistons are slightly different design but the wrx and sti have the same compression ratio, same head gasket and obviously the same stroke etc as its the same basic spec uk 2.0 MY03-05, so it only leaves the head- does it have a different size combustion chamber? that or even though the piston crown is different shape it may not be a different 'cc' size. thats what im trying to find out- will it need a different head gasket or it wont change anything when used with the wrx heads

bigsinky

if they are the standard pistons and rods then compression should be same. i am unsure but does the STi heads not have AVCS.

techno_brat

iTrader: (5)

yeah standard sti pistons, or maybe using a short motor but with wrx heads. yeah the sti heads are AVCS so im not sure if the head volume is the same as a wrx?

techno_brat

iTrader: (5)

bump- anyone put a newage sti block on wrx heads? did you have to use a thicker headgasket or was it straight fit?