The WRX intercooler is located on top of the motor underneath the hoodscoop. In your oppinion do you think that this is a good idea and works well or is completely pointless and defeats the whole purpose of an intercooler? I have heard it both ways as a good and bad set-up for the WRX and STI so now I turn it over to you all for your two-cents.

:dunno: :dunno: :dunno: :dunno:

Here's some pictures of the Subaru intercooler set-up:

http://www.xcceleration.com/images/viva/wrecked4.jpg
http://www.allcarwallpapers.com/wallpapers/previews/subaru-impreza-wrx-sti-101.jpg

I've said it before and I'll say it again, I think it is a shit idea. A front mount or even somewhere towards the front of the engine would be much more efficient. How is something supposed to cool air when it is sitting on top of a motor getting all sorts of heat soak, and touching other metal parts of the motor reaching temperatures of 210+ degrees? Whether it is getting air rammed into it or not, I don't think it is that efficient. It is better than nothing, but my vote goes for a front mount like on the EVO.

what is the idea/advantage from wrx engineering standpoint?

I don't like it... unless you can somehow get tons of cold air to it, there are much better locations....

i remember hearing that the air is colder and denser right off the windshield, thus the reason for a functional cowl hood (forgive me as i have been out of the loop for years now)

I think it looks cool where it is but it doesn't serve its purpose there. Its more like a lukewarm intercooler.

i remember hearing that the air is colder and denser right off the windshield, thus the reason for a functional cowl hood (forgive me as i have been out of the loop for years now)
I don't see how it would be any denser than at the front of the car, at a low position... cowls work by creating a sort of vacuum as far as I know, pulling the air in, vs. having it rush over/into it...

There is no cowl hood. It uses a big ass scoop. Heat soak and inefficiency becomes a problem mostly at high speeds as air starts to just fly over the scoop. A FMIC MIGHT bring in a pressure drop in intake, but I have my doubts as to whether it will make that much of a difference...unless the design is shit.

On the WRX it seems reasonable as the turbo is so damn small. The STi trbo is a bit bigger and might warrant a FMIC when increasing boost. Do they use the TMIC or FMIC on the stage rally cars? I would use a TMIC in that case unless it serously hindered my output.

Besides...you don't want to lose the functionality of that hood scoop do you? :D I haven't been on the WRX boards in a long time to tell whether people are seeing noticeable gains from just a FMIC. I have my doubts that they do though.

Yes the air IS colder/more dense at the hood scoop area and warmer at the FMIC area. Subaru engineers were not idiots when they chose this design. The FMIC causes too much lag for the stock WRX Turbo. Another reason for the TMIC is because in WRC, there is much less chance of damage to the IC.

I think the TMIC is a good location for stock or mildly upgraded turbo cars like mine.
Even when it was 110+ degrees outside i could drive my car open the hood and put my hand on the intercooler and it was warm,but not hot.

I do agree that for traffic situations that the intercooler does get heatsoaked but when you start moving again it does cool back down fairly quickly.



03Flat4 WRC uses a FMIC just located higher than a normal FMIC in the grill area.you should know this :) :)



I vote +1 for it being a good location

I think the TMIC is a good location for stock or mildly upgraded turbo cars like mine.
Even when it was 110+ degrees outside i could drive my car open the hood and put my hand on the intercooler and it was warm,but not hot.

I do agree that for traffic situations that the intercooler does get heatsoaked but when you start moving again it does cool back down fairly quickly.



03Flat4 WRC uses a FMIC just located higher than a normal FMIC in the grill area.you should know this :) :)



I vote +1 for it being a good location

You want a cookie? :D

Anyhow, there is a nice mod to raise the intercooler in the back so that it tilts toward the air. I'd do it if I wasn't thinking of getting a larger one.

I'd just get a bigger turbo and a front mount....I still stand by my opinion that the location sucks. It's good for stock, much better than some stock intercooler locations, but the front mount is king IMO, a front mount with a scoop is god :)


Any of you guys have programs to monitor your IATs (Intake Air Temps)

I'd just get a bigger turbo and a front mount....I still stand by my opinion that the location sucks. It's good for stock, much better than some stock intercooler locations, but the front mount is king IMO, a front mount with a scoop is god :)


Any of you guys have programs to monitor your IATs (Intake Air Temps)


I stilll think it depends. Ideally, there should be 2 boost gauges. One at the turbo, and one after the intercooler. Especially with FMIC. It is optimal to know the PSI that is actually going into the engine. The drop will be greater, so even if your turbo is pushing out 18PSI, your intercooler may be dropping the pressure down to say 15(arbitrary number). You are assuming that everyone is going to upgrade from stock turbo, which is assuming too much imho. Not every WRX buyer upgrades their turbo, which then does not necessitate a bigger IC or even a FMIC. I agree wholeheartedly that a big turbo needs a FMIC for many reasons, negating the pressure drop problem.

If you want the big performance is it hard to re-mount the intercooler to the front??

Yah you would have to buy a intercooler and some piping, but again if the air IS cooler it would have more air going through the turbo.


Remember guys, subaru is probably not going for the 1/4 mile record from the factory. As you all know the subaru* label has been known for the durable, WRC, and long-lasting so they probablyu were trying to balance the power and the economical standpoints at the same time.
Also...they probably know somehting we dont...there got to be a VERY good reason for why they mounted it on the top...just think bout it.

---go with your preference---

ok hold on to everyone!! you must remember the EVO and the STI are 2 different cars.... the evo is a i-4 at 180-degree angle meaning that the turbo is located infront of the engine, but sti are flat-4 boxer engines, where the intercooler inlets (where the IC piping enters the engine) is on top of engine.... so there is a basic perpose for the top mount.... plus, WRC 2005 rules state that the rally car must must have a production version, and theres no way to stick a huge 30 in. intercooler on a stock sti (would be awsome though).... so dont forget, everything built has a real purpose....

ok hold on to everyone!! you must remember the EVO and the STI are 2 different cars.... the evo is a i-4 at 180-degree angle meaning that the turbo is located infront of the engine, but sti are flat-4 boxer engines, where the intercooler inlets (where the IC piping enters the engine) is on top of engine.... so there is a basic perpose for the top mount.... plus, WRC 2005 rules state that the rally car must must have a production version, and theres no way to stick a huge 30 in. intercooler on a stock sti (would be awsome though).... so dont forget, everything built has a real purpose....


well said!

I'm sure it's been said before, but as far as turbo lag, and pressure drop across the intercooler a tmic makes a hell of a lot more sense than a front mount

C'mon up to Montreal for some winter rallying, plenty of cold air outside, and you can suck out all the heat you can get by the heater !

I'm sure it's been said before, but as far as turbo lag, and pressure drop across the intercooler a tmic makes a hell of a lot more sense than a front mount
Agreed. hence why Subie chose that as the stock location rather than the FMIC. The end user may add more boost and hence may feel the added ability to cool the intake charge previous to the intake more important than minimum lag time.

IMHO yes, unless you have a much larger turbo. The larger (STI+) size TMIC handle all IHI series turbos decently without the pressure drop a FMIC will give you.

:loco:

If you upgrade to a turbo that is efficient at the boost you are running, the stock IC is plenty.
A 16g @ 15psi makes FAR less heat than the stocker @ 15psi.
To me the STi intercooler is a joke. There is almost no more MASS than the wrx unit.
An intercooler is not very efficient at taking heat from the charge and putting it directly into ambient air, you need MASS to hold it out of the charge untill it can be dissipated by airflow.
Thats why temp will go up on a long high boost run, the IC has maxed its thermal capacity to retain heat.

Just my 02.


Oh,. and hello all...

Whoever came up with that location should be shot. You have to be careful when working on the engine as the fins are easily bent. Not to mention the loss of airflow thru the radiator. I have a 2004 Baja Turbo and just spent four hours straightening the fins. Caused my turbo to go tits-up.

Dude, necro much? Holy crap, this thread is 2.5 years old.

Whoever came up with that location should be shot. You have to be careful when working on the engine as the fins are easily bent. Not to mention the loss of airflow thru the radiator. I have a 2004 Baja Turbo and just spent four hours straightening the fins. Caused my turbo to go tits-up.
Not only is this thread extremely old, but I have issues with your post in general.

First, why do you need to be careful not to bend the fins on your TMIC? Are you putting tools on it? It shouldn't be bending just by you putting your hand on it.

Second, how does a TMIC block airflow through your radiator? A FMIC would block air, but not a TMIC.

Third, how did bent fins cause your turbo to fail? I cannot think of a way that it is possible for bent fins to cause turbo failure.

Whoever came up with that location should be shot. You have to be careful when working on the engine as the fins are easily bent. Not to mention the loss of airflow thru the radiator. I have a 2004 Baja Turbo and just spent four hours straightening the fins. Caused my turbo to go tits-up.


i think its you who should be shot, and anyone who know thermodynamics can tell you that the hood scoop takes in the cold air while moving (even if its 90 d outside and your moving at 30mph the air will be around 75d. also the hood scoop has air being slammed right into it because of the large surface area and the fact that a hood is aerodynamic it basically directs the air right in.

also cold air travels down while hot air travels up in the process you have cold air cooling the top of your engine and your turbo, while you have the bottom open it is being cooled as well. i think its a good design rather then front mounted.

sorry for reviving an old thread.

This is getting ridiculous now. Bigred.... stop. This thread was over 2 years old.