I was wondering your opinion on Hood Mounted Intercoolers. Subaru seemed to have sucess w/ them, but that may be due to their upwards facing throttle body. I dunno.

Maybe not ideal for a honda w/o a hoodscoop, but how about the theory in general?

 

no room.

 

im not talking about in a honda specifically... someone told me they dont work as well as a FMI ... mainly because hood temperatures work against the cold incomming air.

 

the reason that they aren't that great is because they become great heat-sinks when you're sitting in traffic. They're usually right over the engine

 

dude you avatar is killing me


so funny


Rob

 

i don't think its that great of an idea either...if it was most people wouldn't convert to fmic when they up the boost right?

In anycase my brother's wrx runs extremmmmmmmmmmmmmely hot....i mean u touch the outside fenders and it actually burns. I can't see how putting the intercooler on top of the engine actually helps considering a.) the scoop only allows so much air coming TO the intercooler (just in surface area alone you can tell a fmic will get more air) b.) heat rises...so all that engine heat will heat up the intercooler more c.) it's a tight fit (meaning very little circulation).

The idea seemed real cool in the begining to us also..but after researching in several subura forums it has become aparent why alot of people switch over to the fmic (it's not a cheap upgrade...i believe blitz is charging around 1G for it).

 

Where would you mount it?

 

OK, I think something 95% of you forget is air flow (not charge air, but outside air). I'm not talking getting air TO the core. That's the easy part. I'm talking about what to do with the air after it goes through the core. Now, let's just forget about heatsoak from the engine and turbo and just concentrate on airflow to and from the IC...

Your inlet should be between 25% and 50% of the total core area not counting the end tanks (if your core is area 200 sq. in, then your inlet area should be 50 to 100 sq. in). Then, once it goes through the core, where does it go? Let's take a look at the Subee IC. Hey, it sits on top of the engine so the inlet won't get clogged with snow when you're rallying and stuff it into a snow bank. BUT... where does the air go after it goes through the IC? Bam, hits the engine. I'm sure I don't have to tell you how bad this is. To ensure proper airflow and no high pressure in the inlet tract (this would actually keep air from going through the IC core), your outlet should be roughly 200% of the inlet.

So... You have a 200 sq. in. intercooler core... Your inlet should be between 50 and 100 sq. in, and your outlet should be between 100 and 200 sq. in. This is easy if you have an FMIC because you have this big open space between the IC and the engine.

But we're not done yet!

Let's look at where the air can go after it gets through the FMIC.. down. That's the only place it can go. Under the car where there's a nice low pressure from your sooper tite JDM Spoonie front lip. This is all well and good, but by diverting the air flow under the car, you're raising the pressure under the car, negating the effect that front lip has on the downforce of the car.

So where do we have it go if down isn't good?

Up. Up through the hood. You know those riceboy hoods that you see on RX7s and Supras with the vents at the front? Those actually improve performance. Now, the air coming through the IC is high pressure air, and since high pressure will always move to low pressure (not the other way around), it's going to want to head towards the low pressure area above the hood. But since under the car is a low pressure area, it's going to want to go that way too, so you're going to have to duct, ot at least deflect, the air up so it goes out through the hood vent. An added benefit of ducting it up through the hood is a bit more downforce.

*deep breath*

I kinda got off track there, but to answer the question, with proper air management, a HMIC could be almost as effective as the FMIC, but it'll take more work to make it such, and there will be compromises.


[Modified by F=WT, 12:23 AM 8/4/2002]

 

Hey, I'm curious... did I just totally go over everyone's head, or do y'all just not care? Generally, on something like this, there's follow up questions and a continuing conversation... *shrug*

 

Not over mine, but I don't have anything to say.

 

FMIC will get best air flow because the whole core is exposed to the airflow coming into the engine bay. This will provide best cooling, blah blah blah. HOWEVER, this does block and heat the airflow to the radiator... which is why many prefer a TMIC; especially those who like to road race, circuit race, etc. Plus, for applications like the WRX, the TMIC upgrade is easy, quick and simple.

Basically depends on what you wanna do. Many run a FMIC without problems with overheating, but as many of you may have experienced with hot summer weather... overheating does occur. So in this instance, getting maximum cool air into the radiator is a good thing. My friends RX-7 has troubles with overheating... I can only imagine if he ran a FMIC...

 

There are two reasons Subaru uses a TMIC:
1) It's easier to make crashworthy.
2) In the WRC, they did not want the intercooler, one of the most vital parts on the car, to become damaged.

 

heat soak owns...

 

I think the point was that this is one of the major downfalls, even considering anything else. When your IC is the same temp as the charge air, there's no good there.
I was under the impression that the purpose of an air dam was to keep a lower pressure under the car, so that it would have a negative-lift or "spoiler" effect on the car by helping to creat a vacuum; air is being sucked out from under the back of the car, but none is replacing it from the front.

"almost as effective" "more work"...I think that means that FMIC is a better strategy. A non-intercooled car can be made to perform as well as an intercooled one. Does that mean that IC's are crappy? It is true that a HMIC could be effective, but it would indeed require alot more work to do so as well as a frontmount would, on most cars.

As an additional note: I don't think what you wrote is over very many heads in FI. There are some very smart people here.

 

You are correct. BUT, any additional air that is let under there, either by going under the air dam, or through the FMIC and under the engine, is still counterproductive. Yes, it'll be sucked out from behind the car if you have an undertray and/ or diffuser, but still... you're letting air go where it shouldn't be going. This is why the McLaren can haul *** without huge wings and ****; they took the time to study airflow.


Yes.


Perhaps, but how long is the non- IC'd engine going to last at the same boost levels as the engine with the IC? You can also make an engine perform as well without a radiator, but that doesn't mean it's going to last 150,000 miles...

No, but they're a damn good idea.

I didn't think so, but most of the posts here are about what BOV is good, what it sounds like, "show pics of your Integras with intercoolers," ect... and not much theory. I know there's some very smart people here... Jake, Mark, Art, ect...


[Modified by F=WT, 6:15 PM 8/4/2002]