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Old 02-17-2001, 04:02 AM   #1
JGard
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Question Air flow through an intercooler

OK, I've just been getting interested in the whole turbo thing. Now, I know what an intercooler does, and I know basically how it does it. The only thing I'm not too sure of, is, in which way does the air flow through the intercooler?

When I think about it, it seems like the thing would actually help decompress the air, and disrupt the flow into the manifold. Is that right?
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Old 02-17-2001, 07:04 AM   #2
yebokmj
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Jim,
I will let you borrow Maximum Boost if you would like. It goes into detail about everthing. There is a whole chapter on Intercoolers.
Joshua
Subaru Salesman
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Old 02-17-2001, 07:09 AM   #3
Tony
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The restriction to the compressed air flow from the turbo throught the intercooler is far out weighted by the fact that your air charge going to the engine is denser (can cram more air into the engine for any given psi) and that the charge is cooler (lets you run more boost safely since there is less chance for detonation).

The air flow is from the turbo (very hot compressed air) to the intercooler end tank (kind of like a header to distribute the flow to the many passages). Then the air is pushed into one of the many small passages, all in parallel, and then they collect in the end tank at the other end which is in turn connected to a tube that takes the cooler, denser air to the engine. The cooling is done when the air is in the many little passages because there is cool air from outside the car flowing over these.

Hope this helps. A great book that'll teach you a lot about turbocharging and isn't too difficult to understand is "Maximum Boost" by Corky Bell, about $20 from amazon.com.

Tony
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Old 02-17-2001, 08:11 AM   #4
WRX1
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What style of intercooler is going o do a better job at cooling the air, A top mount or front mount? I am assuming that it has been done both ways with the turbo upgrades on the 2.5. Just curious to see if anyone has any air inlet temps or anything.
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Old 02-17-2001, 08:20 AM   #5
JGard
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oh, cool. Thanks Tony. gotcha 100%. And Josh, I'd defenitely be interested in checking out that book.
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Old 02-17-2001, 08:33 AM   #6
mrbell
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FMIC's are more efficient, because they have more air ramming thru them and carrying away the heat. TMIC's have a smaller amount of redirected(read: restricted) air. They also sit above the engine and may have to deal w/ the extra heat from the engine. However, TMIC's have a couple things going for them. One, the whole system is much more compact. Two, it requires much less piping and is therefore easier to build and install. Three, they are more reliable. This is not really by design of the IC so much as it is a byproduct of the location. FMIC's are much more prone to being damaged. At the front of the car, a stone or something can fly up and smack into the IC and then no more boost. Also, if you're going thru mud it can build up and stop the IC from doing any cooling at all. On top of the engine, the IC is protected much better. Reason four, you have a hood scoop, use it!
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Old 02-18-2001, 06:05 PM   #7
Kevin Thomas
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Lightbulb

With the TMIC being so close to the turbo and connected directly to the throttle body, there's generally less heat to be picked up by the piping going to and from it. FMIC's sometimes have problems getting 'heat soaked' with all the extra piping going to and from the intercooler. There's no piping to heat up coming from our TMIC since it's connected directly to the throttle body. The heat I am speaking of is not the heat from the turbine but heat from the engine bay surrounding the turbo piping.

Less lag also then long piped FMIC's.

[This message has been edited by Kevin Thomas (edited February 18, 2001).]
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Old 02-18-2001, 06:44 PM   #8
Penphoe
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Kevin -- speaking of IC's, did you get a chance to try out that small IC from a thunderbird (I *think*) a while back?

LaterZ!
Darren!!
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Old 02-18-2001, 06:55 PM   #9
Kevin Thomas
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Yeah! It didn't fit. The length of it from the throttle body to the firewall was just too long. *sigh* Oh well! Now I have to take my life earnings (which isn't much..hehe) to RalliSpec and get the job done right. Man I'm cheap!
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Old 02-19-2001, 12:40 AM   #10
Jonnathan
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Looking at pics of intercoolers, they all seem to be silver/metallic. but silver is the worst possible colour for something trying to dissipate heat.
Why arent they painted black ?
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Old 02-19-2001, 12:43 AM   #11
Keiho
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Cause they look better silver.
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Old 02-19-2001, 11:39 AM   #12
ejicon
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Is an intercooler really neccessary for a turbo engine? I might need one then.
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Old 02-20-2001, 12:06 AM   #13
roninscar
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They are necessary if you plan on boosting above pedestrian levels.

You need to get that heat out to prevent detonation.

cheers
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Old 02-20-2001, 12:34 AM   #14
micah
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Jonnathan- You're right about the silver, but only if you're trying to give up heat by radiation. Black = high emissivity.

However the dominant mode for an intercooler is convection (air blowing over the metal) so the layer of paint would probably hurt more than it helped. No big deal either way.

cheers
mbs
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