USDM STI shortblock USDM wrx heads. ?s

redrr · 02-22-2006, 10:54 AM

I have a brand new usdm sti shortblock that i am going to put in my 02 wrx. i am going to use the wrx heads. the first thing that i noticed is that the sti block has a port of some kind coming out of the top of the block. it would be under the throttle body if the intake manifold was on. Is this a coolant passage? do i need to use it? or can i just plug it? What else am i going to need for this block swap? i have thicker cometic head gaskets already and arp head studs. what else?

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06Rex · 02-22-2006, 11:40 AM

You might want to move this thread to 2.0L or 2.5l youll have more peps see it

legacy2003 · 02-23-2006, 06:55 PM

i can answer this, as i went through the same thing. the 2 ports coming out of the top of the block are for breather hoses that would normally run into the avcs heads. they spit oil. since you don't have avcs with the wrx heads, you can do one of 2 things, either a) cap the ends of them, or b) modify the black ports on the top of the heads where the breather hoses on the wrx originally go in to accept 2 hoses. that's what i did and it worked great.

cometic head gaskets are a good idea to lower compression to 8:1 like you said; while arp studs aren't necessary it's not a bad idea. i was using both.

get engine management or else your setup will go boom.

sounds like you have what you need to have a good running motor. do not use a td04 on it though (wayyy too small).

any other questions? i have lots and lots of experience with the hybrid motors, so pm me.

StarDogChampion · 02-24-2006, 08:09 PM

so with this swap you want to keep the compression around 8:1 (w/cometic head gaskets)? not the 8.6:1 (w/stock ej257 gaskets)

02-22-2006, 10:54 AM	#1
redrr Scooby Newbie Member#: 108221 Join Date: Feb 2006	USDM STI shortblock USDM wrx heads. ?s I have a brand new usdm sti shortblock that i am going to put in my 02 wrx. i am going to use the wrx heads. the first thing that i noticed is that the sti block has a port of some kind coming out of the top of the block. it would be under the throttle body if the intake manifold was on. Is this a coolant passage? do i need to use it? or can i just plug it? What else am i going to need for this block swap? i have thicker cometic head gaskets already and arp head studs. what else? * Registered users of the site do not see these ads.

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02-22-2006, 11:40 AM	#2
06Rex Scooby Newbie Member#: 105209 Join Date: Jan 2006 Location: Phoenix Vehicle: 2006 WRX Aspen White	You might want to move this thread to 2.0L or 2.5l youll have more peps see it

02-23-2006, 06:55 PM	#3
legacy2003 Scooby Specialist Member#: 38338 Join Date: Jun 2003 Chapter/Region: MAIC Location: Washington, DC Metro Vehicle: 2003 Outback Sdn H6 Black	i can answer this, as i went through the same thing. the 2 ports coming out of the top of the block are for breather hoses that would normally run into the avcs heads. they spit oil. since you don't have avcs with the wrx heads, you can do one of 2 things, either a) cap the ends of them, or b) modify the black ports on the top of the heads where the breather hoses on the wrx originally go in to accept 2 hoses. that's what i did and it worked great. cometic head gaskets are a good idea to lower compression to 8:1 like you said; while arp studs aren't necessary it's not a bad idea. i was using both. get engine management or else your setup will go boom. sounds like you have what you need to have a good running motor. do not use a td04 on it though (wayyy too small). any other questions? i have lots and lots of experience with the hybrid motors, so pm me.

02-24-2006, 08:09 PM	#4
StarDogChampion Scooby Specialist Member#: 10276 Join Date: Sep 2001 Vehicle: 2001 Impreza RS 2002 WRX, 2012 535i	so with this swap you want to keep the compression around 8:1 (w/cometic head gaskets)? not the 8.6:1 (w/stock ej257 gaskets)