Hood Mounted Intercoolers
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Hood Mounted Intercoolers
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?
Maybe not ideal for a honda w/o a hoodscoop, but how about the theory in general?
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Re: Hood Mounted Intercoolers (csufweed)
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.
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Re: Hood Mounted Intercoolers (B-Series Sol)
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
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Re: Hood Mounted Intercoolers (B-Series Sol)
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).
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).
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Re: Hood Mounted Intercoolers (E Swift)
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]
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]
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Re: Hood Mounted Intercoolers (F=WT)
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*
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Re: Hood Mounted Intercoolers (B-Series Sol)
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.
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...
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Re: Hood Mounted Intercoolers (csufweed)
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.
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.
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Re: Hood Mounted Intercoolers (F=WT)
Now, let's just forget about heatsoak from the engine and turbo and just concentrate on airflow to and from the IC...
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.
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.
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.
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Re: Hood Mounted Intercoolers (ion_four)
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.
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?
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.
[Modified by F=WT, 6:15 PM 8/4/2002]
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