Summary: USDM STi TMIC installation

[txl146]

Call them up and give them this PN. I also couldnt' find it on their website.

RST-9085kit Air Splitter & Seal Kit MY02-03 $84
http://www.rallispec.com/

Peak boost is around 18.5psi.

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[txl146]

Air splitter kit has finally arrived today. Splitter fitment was good and is much more effective than WRX splitter kit in directing air into TMIC.

[txl146]

WRX splitter:


Side by side comparison:


Splitter comparison:


Installed:




Directs air through two channels (much more effective in cooling lower section of TMIC).


update: 6/28/06 6:38pm.
Fitment problem was due to trying to install shroud backward... stupid me.

[txl146]

In my opinion, JDM air splitter w/o seal seems to work even better than WRX air splitter w/ seal. I highly recommend that everyone who installs STi TMIC to get this kit.

Based on my experiment, WRX air splitter kit was proven to be ineffective. After 1 hr of driving at 70-80mph, TMIC was heat soaked badly that it was untouchable. I will repeat the same experiment with JDM STi air splitter kit shortly.

[Bishop]

something seems odd about your shroud. i didn't have any fitment issues. can you take a couple more pics? did you purchase the jdm sti shroud?

[txl146]

can you please confirm the PN of JDM STi shroud?

[moss]

Originally Posted by J*Bishop

something seems odd about your shroud. i didn't have any fitment issues. can you take a couple more pics? did you purchase the jdm sti shroud?

Don't you have an 04?

[txl146]

Originally Posted by J*Bishop

something seems odd about your shroud. i didn't have any fitment issues. can you take a couple more pics? did you purchase the jdm sti shroud?

updated:
Fitment issue has been resolved. I installed it backward...

[1illusion]

You sure it wasn't backwards?

I'm not sure of the exact part number I'll look when I get home for the bag, but this was what I used https://www.subarugenuineparts.com/p...roducts_id=783

Without the bellows in place the air chooses the path of least resistance which is out and around the IC. With the correct sized bellows in place, the air is forced through the IC, which passes more air, and more air = more cooling.

[txl146]

Oups... found out that I installed it backward. Thanks 1illusion for the comment.

Must be the weather.....

[txl146]

More pictures:







Comment on final fitment.
Since STi TMIC sits slightly higher due to use of longer TB hose, fitment isn't perfect with shroud. As you can see from above, shroud makes contact with lower section of TMIC (valvetrain pipings). I may have to trim the shroud to create perfect fitment...

[Bishop]

good job! see i knew somethin was wrong. i did the same thing!

[moss]

wonder how all this stuff would work on a GC ...

[Dave_RalliSpec]

Hopefully my post won't get this thread locked because its not posted under our official vendor account....which we have intentionally let lapse because we rarely sell stuff online here. My intention here is to provide technical info....but that is not to say you can't contact us to buy the right parts.

First off....there are differences between USDM and JDM intercooler setups. There are also important differences between MY02-03 and MY04-05 and again to MY06. If you are mixing and matching parts its very possible you will end up with stuff that doesn't fit properly together.

I should mention that we have been selling the intercoolers and the components to fit them properly to USDM models just about since the WRX came out here. We have specialized in importing Subaru and STi products from Japan for the past 5 years and are one of the few companies doing continuous regular shipments from japan. If you need something, we can get it....whether its on our website or not. Just send us an email. On top of that we have extensive knowledge regarding the interchangeability of JDM and USDM products and probably know more about this subject than most other companies out there.

#1. There are three different RH (passenger side) intercooler brackets. There is one for MY02-'03 USDM WRX. There is another for '01-'03 JDM WRX & STi. And finally for '04-'06 all USDM and JDM WRX & STi models share the same bracket although it is a different part number than either of the 2 previous brackets. I would say you could have some issues trying to interchange a Ver.7 intercooler ('01-'03) with a Ver.8/9 bracket and vise versa. I think the USDM Ver.7 bracket and JDM Ver.7 brackets are close enough to interchange without a problem.

All LH (driver side) brackets are the same regardless of WRX or STi or model year.

#2. There are two different throttle body hoses. One hose (part number ending AA030) is for all USDM and JDM 2.0L turbo applications ('01+). The other hose (part number ending AA121) is for all Impreza 2.5L turbo applications. I think that you should use the throttle body hose appropriate for whatever throttle body/intake manifold is being used....i.e. you should not use AA121 with a WRX 2.0L motor.

#3. The y-pipe design and hose lenghts vary depending on year and model. The OE STi 90 degree hose elbows are super expensive so we do not use them. We put together our own Y-pipe kits with custom silicone hose connectors. Up to and including MY04 the STi's used a two piece aluminum Y-pipe design consisting of two separate pieces that attached to the bottom of the intercooler. From MY05 on this was switched to a single aluminum Y-pipe that attached to both intercooler inlet ports. The 90 degree silicone connector is not identical between the two pipes. I think a change may have been made to the intercooler as well to accomodate this different pipe.

#4. The turbo compressor outlets are different between 2.5L and 2.0L turbo models. This is because of the drive-by-wire throttle. The throttle motor sticks out a lot and required a little kink or jog to be added to the end of the compressor outlet casting to clear it. The Y-pipe hose connector is different to accomodate this slightly different outlet position. If you are using a VF-39 turbo off a USDM STi on your WRX then you might need to adjust the lengths of the hose connector on the Y-pipe. And using a USDM Y-pipe assembly with a different turbo might also present some fitment issues.

#5. There are 4 different STi intercoolers. One used from '01-'02 in Japan (Ver.7 basically) is the largest one that has been used. Fitment on a US model requires altering the A/C line for clearance. This intercooler, unfortunately, is no longer available brand new and the part number supercedes to the '03-'04 (Ver.8) intercooler which is slightly smaller in size. '05-'06 intercoolers have a different part number still...may be a change to accomodate the single Y-pipe design as mentioned above.

#6. The air splitters....there have been a number of different STi air splitters. Early ones were steel and had 2 water spray nozzle locations. Then with the Spec C model a lightweight aluminum one was introduced and only a single nozzle location. This is the one we sell for MY02-03 applications. The standard STi (non-Spec C) also went to a single nozzle but was still steel. With each change in hood scoop design came a design change in the splitter. The STi hood scoops being taller then their corresponding WRX ones (until '06 anyway) used a splitter that sat up higher to take advantage of the taller scoop. You cannot use a STi splitter with a WRX hood scoop without having to cut it. Therefore if you should ideally use the STi intercooler, hood scoop, and splitter as a package to get optimum airflow to the intercooler.

#7. The seal for the splitter to intercooler....for all the STi splitters prior to '06 the same seal was used. It is slightly longer than the WRX one because of the larger intercooler area. If converting a WRX to use a STi splitter and seal you will need to get a couple extra clips.

As you can see....lots of different interchangeability issues. It is quite possible to make a lot of combinations go together but they may not always fit perfectly. The only way to be 100% certain of perfect fitment between every component is to use all the proper parts of that particular year together as a package. Otherwise you may need to make modifications or accept a slightly poorer fitment than you would otherwise have.

--Dave
Rallispec
www.rallispec.com

Please do not PM me...I do not check it. Go to the website and use one of the emails listed.

[txl146]

Dave, thanks for the information. I highly appreciate your time to write information about interchangeability and fitment on various models.

Net of it is that USDM STi TMIC and JDM air splitter kit will work great if modified slightly. There may be a slight fitment issue of lower section of shroud contacting TMIC piping (valvetrain). It may be an easy fix by trimming the height of shroud.

This will not happen if you get a JDM STi TMIC.

[Bishop]

Originally Posted by Dave_RalliSpec

#7. The seal for the splitter to intercooler....for all the STi splitters prior to '06 the same seal was used. It is slightly longer than the WRX one because of the larger intercooler area. If converting a WRX to use a STi splitter and seal you will need to get a couple extra clips.

i could have sworn they're different. the usdm and the jdm v7 ones.

[tuellma]

e-gads....
Just bought an '04 STi intercooler for an '02 WRX....
Had no clue there was all these...."issues"

I'm subscribing and will definately have questions.
I have STi Scoop, ZeroSports Splitter, will be interesting to see what stays and what goes....

[vipernj]

nice modding man... i still dont understand.. That tmic fit fine on my car with the stock wrx elbows... the only thing was that the drivers bolt didnt line up perfectly... at least it all worked out... I want to see a fmic on your car soon...

[txl146]

Only way for bolts to line up correctly is to have a longer elbow and TB hoses... I'd love to get a FMIC, but it will cost me $$$ (FMIC plus Protune).

[tuellma]

Got my intercooler on. Had to use a "Tuned by Matrix" hose that I bought at a local shop. It's good for now, but I just ordered the recommended Hose Techniques items.

I'm breaking in a new clutch so boost is not an issue right now.

[cincyrider]

Originally Posted by txl146

updated:
Fitment issue has been resolved. I installed it backward...

Atleast you figured it out. Loooks Gooood.

[02WHITEDUB]

OK, so how again do the JDM v7 and v8 TMICs differ? If you can't get the v7 new anymore and it's part# supercedes to the v8, does the v8 still work with a Spec-C splitter?

How does the JDM v8 STi TMIC compare to 04+ USDM STi TMIC? I know the v7 is HUGE and the v8 is smaller...

[txl146]

Update: 8/4/06

Since the upgrade, I can definitely feel that IC is cooler... this is a mod that is a must for those with STi TMIC on your WRX.

[sluflyer06]

it seems out of all the threads here there is no conclusive data on exact fitment and parts needed....maybe someone here can help....

i've got an 06'wrx and am looking at either a usdm sti tmic or a jdm sti tmic....from what i've read i think either will bolt right up with either a modified hose setup or i've been told that buying the APS tmic ypipe setip for their tmic will fit perfectly with the sti tmics....also do u guys think its worth the $$ for the jdm tmic over the usdm?

with that being said could i just buy the usdm sti splitter and gasket for the 06? its a real PITA having an 06' as the information is sketchy and inconclusive at best on here.

[txl146]

I am sorry... I am not too knowledgeable about 06 model. Maybe someone can chime in here.