WRX Heads on a EJ257 shortblock

Trackhound · **Posted:** Tue Sep 02, 2008 5:01 pm

I'm putting together the above unit using 2002 wrx heads. I am aware that others make a modification to the head combustion chambers to open them out to suit the wider 257 bore. Does anyone have any details of what is involved with this i.e. how much material is removed and from where etc. Thanks

Freon · **Posted:** Tue Sep 02, 2008 6:31 pm

I'd take it to a professional if you wanted to reshape the combustion chamber.

Trackhound · **Posted:** Sat Sep 06, 2008 2:24 am

Thanks -that was the intention - I just wanted to understand what was involved before opening the wallet!

For those who are interested I've attached a pic of the headwork a subaru specialist here in scotland carried out. He opened out the chambers slightly to match the piston profile and wider bore. The heads were cc'd afterwards and the combustion chambers are 51cc.

Justin 05 STi · **Joined:** Wed Mar 01, 2006 10:51 pm **Posts:** 284

Very nice.

What size are the chambers stock, and what will the compression ratio be with 51cc chambers?

®@©E® · **Posted:** Sat Sep 06, 2008 3:54 pm

48cc, I believe
and, 51cc like stock STI volume, so CR would be same.

Trackhound · **Posted:** Sun Sep 07, 2008 1:31 pm

That's right they were previously 48cc. The CR is 8.2:1 with headwork done and using 1.6mm headgaskets.

I understand that the US STI heads are 57cc according to this link:

http://forums.nasioc.com/forums/showthr ... iston+dish

RomRaider

WRX Heads on a EJ257 shortblock

Who is online