USDM STi Swap

spoolinsuby · 01-13-2006, 02:32 PM

I am swaping a STi longblock. I have a shortblock and complete heads, thats it. I need to use all the other stuff from my WRX. Is there anything I need to get this motor in my car? I have gaskets, oil pump, water pump, timing belt, timing belt tensionor, STi oil pan, STi oil pickup, and all of the reusable stuff from the EJ205. Is that all I need? I noticed the PCV system on the STi is a lil different than my WRX. Does anyone have a diagram for it?

Thanks,
Frankie

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SubaFastR · 01-14-2006, 12:44 PM

you need to plug up the AVCS and run your WRX intake cam and cam sensors.

spoolinsuby · 01-14-2006, 01:19 PM

The WRX cam position sensor is on the driverside intake camgear right? I thought I would be able to use just the cam gear and sensor from the WRX.

SubaFastR · 01-14-2006, 08:19 PM

Nope. The STi uses a 3 wire sensor while the WRX uses a two wire sensor. Also, the sensor triggers on the cams are completely different.

spoolinsuby · 01-14-2006, 10:47 PM

I know about the sensor differences. I had thought the WRX sensor used the cam gear as the trigger and not the cam. I guess I'll sell the STi cams and get some aftermarket cams or use the stock WRX cams. Is there anything else I need to know?

SubaFastR · 01-14-2006, 11:53 PM

Ya, to use the WRX factory wiring, you will need to fit a throttle cable style throttle body. I'm not sure, but you may have to move some pins around at the engine harness. You do have to do it to get jdm avcs to work with a stock WRX harness. Don't forget tuning.

spoolinsuby · 01-15-2006, 12:24 AM

I am using all of the WRX electronics, accessories, and a WRX AEM EMS. I'm not worried bout the AVCS since I cant control it with the EMS.

taeyax82 · 01-16-2006, 12:58 AM

well if you are going with sti short block and wrx head it'll just bolt right up.. just get new gaskets and start swaping parts.. so its a hybrid motor.

spoolinsuby · 01-16-2006, 04:22 AM

I have a STi longblock, if I put the WRX heads on it the compression will be too high.

SubaFastR · 01-16-2006, 12:58 PM

No it won't, .2 is nothing. The car will just be more responsive. The compression ratio on the WRX is too low anyway.

taeyax82 · 01-16-2006, 02:47 PM

Quote:

Originally Posted by spoolinsuby

I have a STi longblock, if I put the WRX heads on it the compression will be too high.

you'll be fine with wrx head and sti block.. alot of people have done this.. and i'm going with the same set up.. but i'm going with forged piston.. on sti block..

SubaFastR · 01-16-2006, 05:43 PM

Don't forget to clean up the ports on those heads. If you have the tools to re assemble the heads, take them apart and port them. You won't hurt anything by merely taking out the flashing, but it sure makes a huge difference in power and response.

spoolinsuby · 01-16-2006, 07:04 PM

Isnt the compression around 9:1 with WRX heads?

spoolinsuby · 01-18-2006, 01:25 AM

Quote:

Originally Posted by SubaFastR

Also, the sensor triggers on the cams are completely different.

This is quoted from a thread I made asking about aftermarket WRX style cams in USDM STi heads.

Quote:

Originally Posted by Gruppe-S

As far as I recall, yes, provided you plug all the sensor holes, and pickup the cam position from the cam gear.
Gary
Gruppe-S

Quote:

Originally Posted by Gruppe-S

The WRX cam sensors should work fine (using the cam gear as pickup), and connected off the head.

Cheers,

Gary
Grupe-S

So I dont need to use the WRX cams in the STi heads cuz the cam position is picked up from the cam gear and not the cam itself. Once I get the WRX motor apart I will know for sure but I dont have a stand for it so I havent even touched it yet.

Quote:

Originally Posted by SubaFastR

Don't forget to clean up the ports on those heads. If you have the tools to re assemble the heads, take them apart and port them. You won't hurt anything by merely taking out the flashing, but it sure makes a huge difference in power and response.

I was thinking bout doing that but I'm still not sure if I'm gonna.

01-13-2006, 02:32 PM	#1
spoolinsuby Scooby Specialist Member#: 80182 Join Date: Jan 2005 Location: Spring Hill, FL Vehicle: 2007 Civic Si Sedan Habanero Red Pearl	USDM STi Swap I am swaping a STi longblock. I have a shortblock and complete heads, thats it. I need to use all the other stuff from my WRX. Is there anything I need to get this motor in my car? I have gaskets, oil pump, water pump, timing belt, timing belt tensionor, STi oil pan, STi oil pickup, and all of the reusable stuff from the EJ205. Is that all I need? I noticed the PCV system on the STi is a lil different than my WRX. Does anyone have a diagram for it? Thanks, Frankie * Registered users of the site do not see these ads.

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01-14-2006, 12:44 PM	#2
SubaFastR Scooby Specialist Member#: 5786 Join Date: Apr 2001 Location: RS202	you need to plug up the AVCS and run your WRX intake cam and cam sensors.

01-14-2006, 01:19 PM	#3
spoolinsuby Scooby Specialist Member#: 80182 Join Date: Jan 2005 Location: Spring Hill, FL Vehicle: 2007 Civic Si Sedan Habanero Red Pearl	The WRX cam position sensor is on the driverside intake camgear right? I thought I would be able to use just the cam gear and sensor from the WRX.

01-14-2006, 08:19 PM	#4
SubaFastR Scooby Specialist Member#: 5786 Join Date: Apr 2001 Location: RS202	Nope. The STi uses a 3 wire sensor while the WRX uses a two wire sensor. Also, the sensor triggers on the cams are completely different.

01-14-2006, 10:47 PM	#5
spoolinsuby Scooby Specialist Member#: 80182 Join Date: Jan 2005 Location: Spring Hill, FL Vehicle: 2007 Civic Si Sedan Habanero Red Pearl	I know about the sensor differences. I had thought the WRX sensor used the cam gear as the trigger and not the cam. I guess I'll sell the STi cams and get some aftermarket cams or use the stock WRX cams. Is there anything else I need to know?

01-14-2006, 11:53 PM	#6
SubaFastR Scooby Specialist Member#: 5786 Join Date: Apr 2001 Location: RS202	Ya, to use the WRX factory wiring, you will need to fit a throttle cable style throttle body. I'm not sure, but you may have to move some pins around at the engine harness. You do have to do it to get jdm avcs to work with a stock WRX harness. Don't forget tuning.

01-15-2006, 12:24 AM	#7
spoolinsuby Scooby Specialist Member#: 80182 Join Date: Jan 2005 Location: Spring Hill, FL Vehicle: 2007 Civic Si Sedan Habanero Red Pearl	I am using all of the WRX electronics, accessories, and a WRX AEM EMS. I'm not worried bout the AVCS since I cant control it with the EMS.

01-16-2006, 12:58 AM	#8
taeyax82 Scooby Specialist Member#: 49465 Join Date: Nov 2003 Chapter/Region: Tri-State Location: NY Vehicle: 03 Bugeye Wagon Red	well if you are going with sti short block and wrx head it'll just bolt right up.. just get new gaskets and start swaping parts.. so its a hybrid motor.

01-16-2006, 04:22 AM	#9
spoolinsuby Scooby Specialist Member#: 80182 Join Date: Jan 2005 Location: Spring Hill, FL Vehicle: 2007 Civic Si Sedan Habanero Red Pearl	I have a STi longblock, if I put the WRX heads on it the compression will be too high.

01-16-2006, 12:58 PM	#10
SubaFastR Scooby Specialist Member#: 5786 Join Date: Apr 2001 Location: RS202	No it won't, .2 is nothing. The car will just be more responsive. The compression ratio on the WRX is too low anyway.

01-16-2006, 05:43 PM	#12
SubaFastR Scooby Specialist Member#: 5786 Join Date: Apr 2001 Location: RS202	Don't forget to clean up the ports on those heads. If you have the tools to re assemble the heads, take them apart and port them. You won't hurt anything by merely taking out the flashing, but it sure makes a huge difference in power and response.

01-16-2006, 07:04 PM	#13
spoolinsuby Scooby Specialist Member#: 80182 Join Date: Jan 2005 Location: Spring Hill, FL Vehicle: 2007 Civic Si Sedan Habanero Red Pearl	Isnt the compression around 9:1 with WRX heads?