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-   -   Differnce between a intercooler and aftercooler? (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/differnce-between-intercooler-aftercooler-52155/)

Street King Feb 8, 2002 12:23 PM

Differnce between a intercooler and aftercooler?
 
What is the difference between an aftercooler and a intercooler on a turbocharged car?
The way I see it through basic knowledge is that the intercooler works by cooling the air after the turbo has compressed it so it is more combustable and the after cooler takes exhaust gas and cools it and sends it on its way to the turbos to compress and then to the intercooler then to the intake manifold where it will be combustated and this whole loop done again?

Please some one straighten this mess out for me?
I know an after cooler can be used in aT/C car and a S/C car but the schematics of both systems are totally different!

richelesro Feb 8, 2002 12:32 PM

I've never heard of an aftercooler. Here's what I do know:

Intercooler
Intercoolers are used to cool the charge intake air after it has been compressed by the turbo(s). Since the turbo sits on the exhaust of the engine, it gets really hot. That heat transfers to the air going through the intake and can cause predetonation, which is a bad thing. By using an intercooler, that air can be brought to a temperature where it will not do so. Also, the cooler the air, the more air can enter the chamber and produce power.

Aftercooler?
Once the exhaust gases leave the chamber, the idea is to keep them as hot as possible until they reach the turbo(s). Hotter air causes the turbo to spool faster while cooler air will not turn the turbine as fast. As such, you DO NOT want to cool the air before hitting the turbo.

Now, once the air leaves the turbo, you want the air to leave the air as fast as physically possible. This is one reason that "the best exhaust system is no exhaust system," er go, downpipes, midpipes, and open exhausts. Putting any type of cooler here would (1) be pointless since the temperature of the air shooting out the rear doesn't do anything, and (2) would restrict the flow of air to the rear; both bad things.

CYM TKT Feb 8, 2002 01:59 PM

they are the same thing as far as i know.. i read about it a while back. I think aftercooler is just what people with superchargers like to call thier intercoolers..

DamonB Feb 8, 2002 04:00 PM

Technically what we call in "intercooler" as actually an "aftercooler" because it is in place after the turbo. Some piston aircraft (especially WWII) had engines with turbosuperchargers. The supercharger was geared directly to the crank (many times the supercharger was multispeed; woohoo!!) and it's output was then fed into an intercooler which was then fed into the turbo which then went into the intake. "Intercooler" meaning "between" cooler.

So air was sucked into the supercharger, compressed and passed through an intercooler before entering the turbocharger and getting more compressed and then entering the engine.

maxpesce Feb 8, 2002 04:13 PM

Damon;
You are mostly correct in most applications we misuse the word INTERCOOLER most TURBO or SUPER CHARGED engines have AFTERCOOLERS ie heat exchancers that are AFTER the compressor - INTERCOOLER is more properly used to describe a heat exchanger that is IN BETWEEN two stages of a multi-stage COMPRESSOR setup - be it an Air Compressor, fluid pumps or a two stage supercharger for an internal combustion engine.

billyrohm Feb 8, 2002 04:36 PM


Originally posted by richelesro
I've never heard of an aftercooler. Here's what I do know:

Intercooler
Intercoolers are used to cool the charge intake air after it has been compressed by the turbo(s). Since the turbo sits on the exhaust of the engine, it gets really hot. That heat transfers to the air going through the intake and can cause predetonation, which is a bad thing. By using an intercooler, that air can be brought to a temperature where it will not do so. Also, the cooler the air, the more air can enter the chamber and produce power.

Aftercooler?
Once the exhaust gases leave the chamber, the idea is to keep them as hot as possible until they reach the turbo(s). Hotter air causes the turbo to spool faster while cooler air will not turn the turbine as fast. As such, you DO NOT want to cool the air before hitting the turbo.

Now, once the air leaves the turbo, you want the air to leave the air as fast as physically possible. This is one reason that "the best exhaust system is no exhaust system," er go, downpipes, midpipes, and open exhausts. Putting any type of cooler here would (1) be pointless since the temperature of the air shooting out the rear doesn't do anything, and (2) would restrict the flow of air to the rear; both bad things.

The air gets hot mainly because it is compressed not because of the heat transfer from the exhaust gases. I'm sure some of the heat may come from that heat transfer but a very small percentage.

DamonB Feb 8, 2002 04:40 PM


Originally posted by maxpesce
Damon;
You are mostly correct in most applications we misuse the word INTERCOOLER most TURBO or SUPER CHARGED engines have AFTERCOOLERS ie heat exchancers that are AFTER the compressor - INTERCOOLER is more properly used to describe a heat exchanger that is IN BETWEEN two stages of a multi-stage COMPRESSOR setup - be it an Air Compressor, fluid pumps or a two stage supercharger for an internal combustion engine.

Thanks; you are certainly more correct.

RonKMiller Feb 8, 2002 07:03 PM

Then there is the AFTER Burner, but that's a whole 'nother topic......
Can you say ZZZZZOOOOOOOOOOOOM? Damn I miss my F-16!


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