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Old 11-09-2008, 02:25 PM   #24 (permalink)
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Volvo - '00 Volvo V70 XC AWD SE
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Originally Posted by tasdrouille View Post
The intercooler definitely help pack more air in, but I don't see how it improves fuel economy by itself. In fact it's a significant restriction in the intake. In my TDI there's a 3 psi pressure drop from the IC. Could you please provide a reference?
Ahhh, but that pressure drop you are measuring across the intercooler isn't from a restriction in the IC, it results from the cooling of the air and it is desirable. Pressure drops caused by flow restrictions are bad, but pressure drops caused by cooling are good.

When the very hot compressed air from the turbo is cooled by the IC its pressure (and volume) drops proportionally and so it contains more air molecules per volume than did the hot air (Boyle's Law). This allows even more O2 to be stuffed into your cylinders than if you didn't have the IC.

All things being equal, the IC allows you to use less boost to get the same number of air molecules into the cylinders - and that improves fuel economy (or power, whichever way you want to look at it).

Last edited by instarx; 11-09-2008 at 02:41 PM..
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