True, there are some advantages of a TMIC, but there are also limitations. first, heat soak - enough has been said here already. second, air flow - the whole front "side" of a TMIC isn't in the air stream like it is in a FMIC. third, there are generally size limitations - you simply can't fit a huge intercooler on top of your engine. finally, a TMIC prevents access to much of your engine bay - this isn't a huge deal cause Subaru uses a flat engine of course, but it's another thing to work around when you are working on your car.

The TMIC IC that Subaru fits on the WRX is fine for that car. But everyone I know who has modded their WRXs (which are common as hell in Minneapolis) to the point of swapping turbos has switched to a FMIC which is a pain in the *** on the WRX.

 

I believe that the EVO's whole airflow design is better for several reasons.

#1 On the STI the air going into the top mount has to compete with the air going in through the front, and thus all that air has to work its way down and under the car to exit. Since exactly as much air exits the car as enters it, there isn't probably much going in as the path for the air doesnt allow a lot going out.

#2 The ram air hood scoop is causing drag on the car, which is going to have some counter affect to the cooling bonus of the intercooler. Significant or not, its there, and will really show at high speeds, where the cooling benefit will not increase as fast as the drag deficit.


On the EVO the design with the intercooler in front of the radiator is a little better. Granted the radiator is not getting as much benefit mostly because the air is slightly warmer thus the delta T is smaller so not as much heat transfer.
The real benefit is that the vents in the hood allow a nice air pattern. One is that is allows air a nice path to escape which allows more air coming into the bay. Also that air is drawn across the engine removing heat which means that the radiator does not have to do so much work.
There will be some drag due to it, but it would be signifiantly less than a ram air scoop, and it will allow more air flow at higher speeds and the deficit of drag wont be increasing so much faster than the benefits are.


The STI intercooler is better for insurance rates though, which are heavily influenced by on damage in low speed crashes.

 

Yes, I know how it looks like, I've seen it in real life with the hood open. As to the word tool, I wasn't pointing at you, but in general. Still, your words describe one ("show a little class?" hahaha). I couldn't agree more that FMIC may be more efficient than TPIC. If it was poorly designed...I'm sure Subaru would have changed it several years ago. They're not stupid. I'm sure it also has to do with plumbing efficiency... Don't get me wrong, Evo's design is good/simple. But Subaru's design has much more than what is readily apparent.

 

TMIC
limited in size
shorter piping (less turbo lag)
scoop (more drag)
no radiator blocking
(5MPH bumper)better reinforcement front bumper beam
soaking heat
no IC weight in front bumper (better F/R)

FMIC
At big as you can fit in your front bumper
longer piping (heavier and more lag)
no scoop at all
blocking radiatior
2.5MPH bumper
no soaking
heavier in front nose



The is all I can think of so far, let me know if you guys wanna add anything.

 

Set modding on side, please.
STi - TMIC, less weight
EVO - FMIC, extra reinforcements in front to pass homologation
When you start to mod everything is possible. Try to fit DCCD and front SureTrack to EVO when you'll add FMIC to STi.
So in short both are different but good in stock flavor.

 

It's a company outlook problem. The Evo's have always had FMIC because it's what they deem most efficient for performance. Subaru has always leaned more towards every-day usability, though. And FMIC's run the risk of taking damage from thrown rocks and other such things. So if a TMIC works well enough, why run the risk?

Is it possible they stuck with it because of the boxer engine? Something about it that need's a TMIC with stock setup?

Oh, but for those of you touting Evo superiority over the STi, let me remind you.... 2.0 inline, vs. a 2.5 boxer. Sorry guys, no substitute for displacement. You start saying an Evo is faster because of intercooler placement, you sound like a bunch of Honda tuners.

 

Subaru's
TMIC heat soak.
Boxter engine require long mainfold plumbing to the turbos. You want the turbos to be hot while running and the long pumbing creates a higher pressure drop for the turbo to work. With this setup and the precat due to emission of long plumbing = very high turbo lag.

In general shorter plumbing for TMIC Yes for subaru but, the long exhaust mainfold makes it worst.

Our mainfold comes directly out of the engine to turbo and many people wrap the headers to hold heat for the turbos. With our twin scroll setup we probalby have less lag. However the extra 500cc really throws it off.

Edit: Oh yeah, upipe is a must and a pain to change. Just want to point out the obvious.

 

Huh? What?? Do you forget that either of these cars will beat out a V8 engine car pretty much any day of the week? There's LOTS of subsitutes for displacement. Displacement just adds weight and rotating mass, not to mention more wear and tear.

 

there used to be no replacement for diplacement...but forced induction replaced it

 

I think what he is saying is 2.5L turbo charged is better then 2.0L turbo charged, not 5.0L V8 is better then 2.0L turbo charged. I don't know about the tear and wear, becuase you can't really say a 1.6L I4 last longer then 2.0L I4....But more displacement is easier to make big HP.

 

has subaru ever MASS produced a 2.5L turbo before?

 

Actually, there still isnt a replacement for displacement. Revs and boost may act as a good substitute but increasing those destroys engine life.

 

I'm sure they've done years of research for the testing of 2.5L Turbo. wait, did i say that right, or should have i taken Hucked On Phawneks? muahahaha...

C'mon talEvons...be happy with the Evo for what it is...

 

well what i normally say is

there is no replacement for displacement but forced induction is close

 

i am and i plan on having a silver or black evo ASAP