Why is it one must have a supercharger or turbo before they get an Intercoooler? Like, would one work if you didnt have forced air? It came up in a conversation and I didnt want to answer since I aint a 100% on it.

I supposed it could be done with a naturally aspirated engine, but you wouldn't gain as much from the intercooling, and there'd be a long way for the air to go in between the air filter and the engine itself, making the engine work harder to get its air (to the point where it would probably negate the cooler air).

A turbo or a blower pushes the air through the intercooler on the way to the engine, and even in this case, some boost is lost simply 'cause of the distance travelled. This is counteracted by the cooler air, allowing more fuel to be used without drastically raising EGT's.

In short, I think you could intercool the engine (although you might risk starving the engine of air), but there's no real point to it.

I hope I was able to explain myself well enough...I'm dead-tired; chances are all I just typed up there is gibberish that I'll have to edit tomorrow...

the turbo or supercharger compresses the incoming air causing it increase in temperature, or heat up. The intercooler removes some of the heat. The outgoing air to the engine will be reduced in temperature to at least ambient.

Some people add water sprayers in front of the intercooler to cool the air charge even more.

I had a 740 Turbo with an intercooler.

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Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

Cooler air is denser, and thus, one can gain even more horsies, because more fuel can be delivered as well.

This works in practice with compressed air, but probably has a negligible affect in the combustion chamber with a normally aspirated system.

Had a Chrysler Conquest with an intercooled turbo as well. Interesting to note is that I drove it mainly while in Colorado, and the thinner air prevented me to see boost pressures over 1 psi.

Once back in Texas, I could max throttle at 7 psi. boost. That car really screamed!!!

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Ohhh... I see. Thanks for the info all.

Warden-That weren't any gibberish, in fact probably more intelligent than most people's coherent conversimatation.

if you placed an air-to-air intercooler into your intake plumbing without a supercharger/turbocharger, then you are just cooling your intake air with ... air at the same temperature - no net gain here. Worse, you will also be introducing unnecessary restrictions into your intake plumbing, which will limit air intake.

like what the other members have mentioned, the intercooler is a heat exchanger which removes heat from intake air that is compressed by some form of compressor (engine-driven or exhaust-driven). Exhaust-driven turbochargers impart more heat into the intake charge because of the exhaust heat conducted into the compressor housing (compared with an engine-driven supercharger).

you want this excess heat removed for 2 reasons:
* a cooler charge will be denser, permitting more air/fuel to enter the cylinder, for more power
* a cooler charge decreases the chances of detonation

Could you use a refriigeration unit (something like the AC) to cool your air charge even more?

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if you do that, you will impose a higher load on your AC compressor, since it now has more heat to expel, reducing power to the driven wheels. And imagine what the plumbing will look like ...

i've seen photos of cars attempting a land speed record, with an air-to-water intercooler inside the car, packed with water and ice, just for the run.

Try a Fort Powerstroke Diesel intercooler.

http://www.turbovan.net/mod_list.html

That thing is HUGE!!!

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Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

"i've seen photos of cars attempting a land speed record, with an air-to-water intercooler inside the car, packed with water and ice, just for the run."

We use to run our fuel line through a cylinder of dry ice on the pro rally car. On hot days the difference was notable. But alas we finally got caught.

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Those are benefits, but I think the main benefit of an intercooler is that it takes less energy to compress cool air than it does to compress hot air.

An engine gets all of its power from the power stroke, the other three strokes - intake, exhaust and especially compression - consume energy. With an intercooler, you have cooler air entering the cylinders, so the compression stroke uses less energy, leaving more power to go to the wheels.

This same principle is the reason behind using intercoolers on multi-stage air compressors.

Air-to-air intercoolers work on turbo- and supercharged engines because the compressor increases the intake air temperature and the ambient air is therefore cool enough to bring that temperature back down a bit. There might be some power and efficiency gains from cooling the intake air on a normally aspirated engine, but I doubt it can be done in a fashion that does not result in a net power loss.

dculkin:
OK, I understand the premise of your statement regarding the energy required for compression. The question it leaves me with is what is the effect on the actual power stroke? Meaning, the resultant pressure in the cylinder would be less at ignition given your argument. Less pressure would yield less power, right? What effect would that have on power going "to the wheels"?

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An intercooler does not result in lower pressure at ignition (except for friction losses through the intercooler, which are too small to worry about). The intercooled motor has essentially the same pressures at the beginning and end of the compression stroke, but it takes less energy to get there when you have an intercooler. The properties of air are such that compressing it from pressure A to pressure B takes more energy if the air is hot.

I don't know why air is that way, but I know people have taken measurements and published tables with the properties of air and they found that hot air takes more energy to compress.

The colder the air - the denser the air. The denser the air - the more oxygen it has. That's why NOS makes power. It is very cold and when it is combined with air, fuel and spark it makes a very big explosion. That larger than normal explosion is what is making more power. I think the formula is something like 1% horsepower gain for each 10 degrees drop in temperature.

That's the same reason to use an intercooler in a supercharged/turbocharged application. Pressure heats the air and an intercooler reduces that heat. You can see a very large drop in pressure if your intercooler is not large enough but it can also have a negative affect if it's too big.

when Nitrous Oxide is heated up inside the engine under combustion, it breaks down into nitrogen and oxygen. This additional oxygen allows you to feed in more fuel, for more power.

so the power of NOS comes mainly from the additional oxygen it carries, and less on its cooling effect.