Hey I am just curious if the jdm sti ver. 7 or 8 is the same volume as the usdm stock wrx heads. I know the usdm sti heads have larger volume compared to wrx ones, and I wanted to be safe in case I plan on switching over to sti heads when I do my swap. Thanks all.

-Nate

usdm things dont even compare to JDM things.

V8 are the ultimates for now, best flowing

agreed with hyper

DO a search. There was great thread last year on heads with pics and measurements and all that jazz with Kingpin and Sponaugle and many of the serious tuners around here comparing notes on a number of heads...

i am not talking about how much the heads flow, I am talking about the actual volume of the combustion chamber. i want to know how much volume each combustion chamber contains as to be sure my compression ratio stays the same.

v7 RAC--is 48cc's (factory spec) but jeff sponaugle measured them at 50cc. WRX ones are 52cc's and jeff measured at 51cc.

What setup is this going to be...obviously you have a bunch of other factors to take into account. Hope this helps.

my setup is the following: EJ22t bored 20 over, 2.5RS crankshaft, stock wrx length pauter rods, custom dished CP pistons (for 8.5:1 compression i believe). I am debating between cylinder head setups. I can either go with the stock wrx head, ferrea valvetrain, and crower stage 4 cams, or I can go with the sti ver. 7/8 cylinder head, also with crower cams. I am wondering if I do decide to go with the sti cylinder head, how badly it will affect my compressino ratio.

Sounds nice...any reason you didn't opt for 2.5 length rods also since you are doing custom pistons? What comp. ratio are you shooting for?

the wrx length rods are only 1.2mm shorter than the 2.5 length rods. There are some benefits to running the longer rod, but it was more convinient to run wrx length rods. Also the benefits will be relatively minimal since the length difference is so small. I am shooting for 8.0 - 8.6:1 compression ratio.

my setup is the following: EJ22t bored 20 over, 2.5RS crankshaft, stock wrx length pauter rods, custom dished CP pistons (for 8.5:1 compression i believe). I am debating between cylinder head setups. I can either go with the stock wrx head, ferrea valvetrain, and crower stage 4 cams, or I can go with the sti ver. 7/8 cylinder head, also with crower cams. I am wondering if I do decide to go with the sti cylinder head, how badly it will affect my compressino ratio.
http://forums.nasioc.com/forums/showthread.php?s=&threadid=423564&highlight=cam+info

I would just stick with the wrx heads if your going with the cams. Trying to put the crowers in the jdms seems like a waste.

what makes you say that, because i cant use avcs?
On a note on the heads. I was told that the wrx heads are 52cc, and the jdm heads are 48cc. If my compression ratio would be 8.5:1 with the wrx heads. My compression ratio would be 8.89:1 with the jdm heads. This is a little high for me. Do I want the upgraded flow of the jdm heads? or do I want more boost and more timing advance out of lesser heads. I am leaning towards the latter.

totoherbs, i wish you wouldnt send me a link to a thread with 173 posts, mainly about engine codes, without pointing out a specific area of the thread. I appreciate the help though.

what makes you say that, because i cant use avcs?
On a note on the heads. I was told that the wrx heads are 52cc, and the jdm heads are 48cc. If my compression ratio would be 8.5:1 with the wrx heads. My compression ratio would be 8.89:1 with the jdm heads. This is a little high for me. Do I want the upgraded flow of the jdm heads? or do I want more boost and more timing advance out of lesser heads. I am leaning towards the latter.
With a turbo larger ports do not matter that much, all they will do is move your power band over some. The cams will more then make up for the small port wrx heads.

totoherbs, i wish you wouldnt send me a link to a thread with 173 posts, mainly about engine codes, without pointing out a specific area of the thread. I appreciate the help though.

Ya, doing your own research sucks huh... :lol:

i have done plenty of my own research, and yes it does suck