Welcome to the North American Subaru Impreza Owners Club Thursday June 30, 2016
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Built Motor Discussion

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 03-17-2009, 07:14 PM   #1
robwrx19720
Scooby Scammer- Do Not Buy From User
 
Member#: 180582
Join Date: May 2008
Default Sti heads or wrx heads

I have a sti ej257 block that im going to build for my 2.0l, the sti block had came with heads. but im not sure if i should use the sti heads or my stock 2.0l heads. what set of heads should i use for the build?
* Registered users of the site do not see these ads.
robwrx19720 is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 03-17-2009, 07:19 PM   #2
hustleshark206
Scooby Specialist
 
Member#: 182227
Join Date: Jun 2008
Chapter/Region: NWIC
Location: seattle, WA/ Jackson WY
Vehicle:
2000 MPS Built RS
1991 Leggy Turbo EJ22t

Default

What type of engine management are you using? If you are going stand alone then the STI heads for sure. If you want to utilize your factory ECU then perhaps the wrx heads would be the easiest since you can use all of your factory wiring. You might be able to use the STI heads and your stock intake manifold but I am not sure.
hustleshark206 is offline   Reply With Quote
Old 03-17-2009, 08:00 PM   #3
blkwagon
Scooby Specialist
 
Member#: 102857
Join Date: Dec 2005
Chapter/Region: BAIC
Location: Fresno Ca
Vehicle:
RHD sedan sti swap
high on meth

Default

you can use sti heads with your stock intake mani and wiring harness but wont be able to take advantage of the avcs with out some sort of controller. Also depending on the year of the head some had a provision for the cam sensor mount in the front that needs to be drilled and tapped. If not you have use a cosworth cam angle sensor adapter to mout the cam sensor in front. The 2.5 heads will give you the correct compression number with out having to go to a thicker head gasket. Using the 2L heads with the 2.5 block will give you a higher than stock compression ratio.
blkwagon is offline   Reply With Quote
Old 03-17-2009, 09:23 PM   #4
robwrx19720
Scooby Scammer- Do Not Buy From User
 
Member#: 180582
Join Date: May 2008
Default

the heads came out of a 05 sti
robwrx19720 is offline   Reply With Quote
Old 03-17-2009, 09:42 PM   #5
EGY5
Scooby Specialist
 
Member#: 165206
Join Date: Nov 2007
Chapter/Region: MAIC
Location: Columbia, MD
Vehicle:
2006 WRB DPSti
w/ white shoes

Default

I personally can offer no useful advice except I was searching for this earlier and I found this advice, from Maxwell Power (Sponaugle level of knowledge)

From this thread, where the guy is literally asking the same thing (2.5L block, which heads?)
http://forums.nasioc.com/forums/show...ighlight=heads

Quote:
Originally Posted by Maxwell Power View Post
my advice is to match the heads to the bore/block.
And just an FYI, taken from this thread:
http://forums.nasioc.com/forums/show....php?t=1667168

Quote:
Originally Posted by Maxwell Power View Post

Now lets do the compression ratio calculations:

Combustion chambers:
06wrx heads (D25 casting): 50cc
04-07 STi (B25/V25 casting): 55.5cc
02-05wrx (S20 casting): 49 cc

Factory compressed HG thickness .026"

EJ257 block on B/V25 STi head: 8.24:1
EJ257 block on D25 WRX head: 8.74:1
EJ257 block on S20 WRX head: 8.84:1

EJ255 block on B/V25 STi head: 8.07:1
EJ255 block on D25 WRX head: 8.55:1
EJ255 block on S20 WRX head: 8.64:1
Remember that the EJ255 is the same as the EJ257 except for the pistons
EGY5 is offline   Reply With Quote
Old 04-13-2009, 09:41 AM   #6
FuJi K
Scooby Guru
 
Member#: 3687
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
Vehicle:
MY99 GF4 JDM 6spd
NF Performance

Default

Quote:
Originally Posted by EGY5 View Post
Remember that the EJ255 is the same as the EJ257 except for the pistons
It's not the same for the heads. Different combustion chamber.

However I want to see a set of '07 STi heads because that looks to be the same casting as the '06+ WRX heads, but still running different combustion chambers.
FuJi K is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
wrx heads/sti block, current wrx heads ej20g 4banger4dr Built Motor Discussion 6 11-14-2009 03:55 PM
STi or WRX heads MS WRX Built Motor Discussion 3 01-30-2009 06:58 PM
LTB sti or wrx head 04+ Sc00byDrew NESIC Private Classifieds 0 10-21-2007 01:22 PM
Wtb Sti Or Wrx Heads apsrex Private 'Wanted' Classifieds 0 09-25-2007 10:32 PM
WTB: Ver.7,8 Cylinder heads, or WRX heads 17cTSi Private 'Wanted' Classifieds 1 07-14-2004 07:41 AM

All times are GMT -4. The time now is 11:58 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2016, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2016 Axivo Inc.
Copyright ©1999 - 2016, North American Subaru Impreza Owners Club, Inc.