I am fairly confident that a lot of this has been covered elsewhere, but I figure that I should share my adventure in the hopes that others will find this informational. 

I decided to install a TMIC from a 04 WRX in my 04 foz. In the beginning I thought that it would be easy enough. In fact it was, but I needed a few other things first. The Install requires a few modifications and a few non-OEM parts but it is completely reasonable to accomplish given the right time and some patience. 

I used the following things during the course of the install:

2004 WRX TMIC (Top mount intercooler)- Ebay

2006 Impreza STi By-pass valve and gasket (thank you Subarude)

2004 WRX silicone hose and metal Y-Pipe- Ebay

2004 WRX Y-pipe gaskets-Ebay

Blue Caliper Paint, Black engine paint, Grey engine primer (1 can each)

My imagination, sorry cant find this on ebay...

Elbow grease- Had trouble finding this, had to use my own..

Clamps, 1/4"x 1, 2" x 2, 

Napa Radiator Hose PN# 8654

About 4 hours of time...



I began by tearing everything out. I can provide step by step Pics, but You'll get the Idea by the pictures. They are in order as I did them.

I removed the Intercooler. Two bracket bolts, Undid the band clamps at the Turbo and the Throttle Body. 

Remove the PCV valve hoses. Remove the BPV by taking out the bolts, Pushed it out of the way for now.

I pushed the A/C line out of the way and wiggled the assembly until it was free of the TB and the Turbo. Out she came!


Here is the pesky Recirc hose that can only be removed WITH the TB out of the way! I had to Unbolt it and CAREFULLY push it towards the fire wall. There are TWO brackets holding the metal tube in place. One under the BOV in this pic and the other directly under the TB behind the wire harness. Id remove the first one then bend the hose out of the way in order to better access the second under the TB.


Here is a size comparison. Some say that there is no difference between a WRX and a FXT. Here is the proof. Id say this was a lot more then 25%.

With the TB out of the way, you can see here the hose clearly. With it out of the way and the  rubber hoses removed, there is all kinds of room to test fit the WRX intercooler. 

After a test fit, I began measuring the Napa Hose or fitment. The hose is a lot longer than is required and some trimming will happen. I decided to cut at the BOV end instead of the Turbo end here in the picture. I ended up taking almost all of the bend at that end away in order to get the BOV to line up with the TMIC correctly once everything was in place. The TMIC Y-Pipe was too long so I had to trim it as well. I matched it up with a pipe setup I received with the tmic. The Bend was correct, but the hose was trimmed extensively in order for the TMIC to sit right and allow for everything to line up. I did run onto a small problem with the TMIC TB pipe coming into direct contact with the vehicle TB. In the end everything lined up, but it took some elbow grease and some skin to get it there. Trim and re seat, trim and reseat, until all was in alignment. PHEW, this took over an hour to get it right.
Below is the NAPA hose trimmed to its final length, though I had to weave the hose through all the connectors to the TB, then bolt the TB up with the hose pushed out of the way. *Make Sure You Keep EVERYTHING out of the TB while it is off or youll have a really bad day* Realign the gasket and rebolt it back togather. Squeeze the hose back under the TB and move on. The hose will squish alittle, it should be fine, it is only a return. It has not effected my vehicle yet, but...

After all the resizing, I finally got it all togather. The PCV valve hoses are a might bit small for the WRX metal piping. I used a lighter to heat the hose and they went on nicely when they were alittle warm. Be carefull not to get them to melting, you only need alittle heat and some aggressive negotiations to make it all work. I have not been able to align the TMIC with the stock mounting brackets, The TB neck issue came into play. The TMIC just would not go low enough to match up with either side. If any one has found a way to get them to meet, I would be more than happy to use that knowledge. For now though I have the drivers side bracket in and the TMIC is supported on it but not bolted. I gave the TMIC a good shake and it is really tight in there with almost no movement in either direction. I dont think it will go anywhere.....
I test started it and ran it a bit after. NO CEL's and no malfunctions, but I can tell you that the turbo spools faster and she appears to have more power. 
MAKE SURE YOU RECONNECT ALL CONNECTIONS. Having to remove everything to reconnect something will ruin your day...just sayin'
MAKE sure all hose clamps and especially the Turbo clamp is really tight. 
DO NOT over tighten the TB bolts when you reassemble the TB, Cracked Intake will result and ruin your weekend!
Wear gloves! Unless of course you enjoy the sight of blood. The work area is tight and I had to remove the TMIC at least 4 times to get everything trimmed and aligned right, with out gloves, I know I would have been hurtin'



New member
When I installed my sti TMIC on my 04 forester XT I wanted to kill the subaru designer who designe Dothan damn recirc hose!!! The wrx hose is so much more simple and easy to install/uninstall.



Yeah i noticed that too, Im gonna blow it out with an air hose asap. Then wash the engine bay out. Damn rodents!!



Subaru Ambassador- AdidaSubarus
Nice install, but the some people that say there is no difference in size, would be correct. It may appear bigger, but it's really not any different internally. When funds allow, get your self an STi intercooler. You have now taken all the steps you need to do, and the STi intercooler is quite a bit larger than stock. And I know all about the tight spot to work in! I had my intercooler out many times when I had mine, just for little things here and there. You get better at it each time lol. Nice work!

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So is the STi Intercooler Bar and plate? V.S the WRX and XT? Or are the internals the same and the size is just bigger than WRX? For me it was a money thing, 300+ for STi with the logo or $50 for a WRX Intercooler. Would I need the STi in the case I go stage 2 down the road?



Subaru Ambassador- AdidaSubarus
I believe the STi is made the same as the others, but much larger surface area, and great flow. And if you shop around you can find an STi intercooler for under $200. I bought my USDM one for $150 shipped. And $50 for a regular 02-05 is too much in my opinion. You can often get them for free, or around $20. The 06-07 WRX intercoolers are usually more, but they are the same as the FXT one, except they use the WRX style BPV flange, just like the 06+ FXT's.



New member
i got a new forester inter-cooler with a new wrx bov but i can get the hose from the bov to fit with the turbo  metal pipe, that was not clear how you do it its seem like you removed the metal pipe and use a straight pipe ima right?

 i was about to go buy an 90 elbow two of them to make it fit? any tip? what is the size of the hose i need since the wrx side hose to the bov is bigger in diameter to the pipe to the turbo??


on the third picture should i use to hose or it wont make any difference ?

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Well-known member
You need either a 04+ Sti recirculation hose or a 06-07 recirculation hose which can be had from any Subaru dealer for around $30

And the y hose in the third pic will make a diff. But nothing you going to feel on the butt dyno



New member
You need either a 04+ Sti recirculation hose or a 06-07 recirculation hose which can be had from any Subaru dealer for around $30

And the y hose in the third pic will make a diff. But nothing you going to feel on the butt dyno
thx you so much, i had it but i cut it bcuz i thought it was not good not knowing i had to remove the metal pipe i should have watch this forum first. : (

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