Here is some technical background about intercoolers. When you compress air or any gas for that matter it heats. There are relationships in classical thermodynamics that mathematically describe this. The one that comes to mind is the isentropic compression. If you compress air from 14.7 psia to 29.4 psia, the temperature would rise from 70 F to 186 F. You cannot let 186 F air go into your engine because it will cause the engine to knock. So you cool it through a heat exchanger. The cooling also increases the density of the charge allowing more oxygen to enter the engine and hence more power to be developed. The intercooler is an air to air heat exchanger.

Expressed mathematically, the relationship is

t2 = t1 * (p2/p1) ** 0.286

where t2 is the final temperature, t1 is the initial temperature expressed in degrees Rankine.

p2/p1 is the pressure ratio of absolute pressure

0.286 is a constant derived from the ratios of specific heat of air which happens to be 1.4. The ratio is the specific heat for constant pressure divided by the specific heat for constant volume.

So at 70 F which is 530 Rankine and a 2/1 absolute compression

t2 = 530 * (2) ** 0.286 = 646

Expressed in Fahrenheit degrees, t2 = 646 - 460 = 186 F

Note that if you use 100 F ambient air, you would get

t2 = 560 * (2) ** 0.286 = 683

t2 = 683 - 460 = 223 F

So a 30 F rise in ambient temperature causes a 37 F rise in pre intercooler temperature.

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Lawrence Coppari

2002 SLK32 AMG
2005 Acura TL
1987 328GTS
1986 944T