An air-to-air intercooler is constructed similarly to a car's radiator. It has a large, airtight volume inside with a large surface area. Compressed air from the turbocharger flows into the intercooler and transfers heat to the intercooler by conduction. The intercooler itself is generally mounted in the front of the automobile where fresh air passes through its vanes and bleeds off the heat. The cooled air then exits the intercooler and is fed into the intake system of the automobile.

Intercoolers are different from radiators in that they must be airtight, i.e. free of boost leaks, and they should present as little restriction to the airflow as possible.

Intercoolers are generally rated on their efficiency, or on how well they remove heat from the compressed air. It should be obvious from this discussion that using such a setup, it will be impossible to cool the compressed air to less than the temperature of the ambient air. Therefore, air-to-air intercoolers will work much better in the cooler months than in the dead heat of summer. An excellent intercooler will get you close to ambient temperature.

Air/water intercoolers circulate water through the intercooler housing to remove the heat instead of relying on the ambient airstream.