Power and Performance III Tuners Practice Test

The key idea is that heat is rejected to the outside air directly through a finned surface. An air-to-air intercooler does exactly that: hot compressed air passes through the intercooler, and the fins along the outside transfer heat to the ambient air flowing over them. No liquid medium carries the heat away in this path, so the heat goes straight into the outside air via those fins.

In contrast, air-to-water and water-to-air setups move heat into a liquid first (water), which is then cooled by air in a separate radiator. The heat is not dumped directly to the outside air across the intercooler fins in the same way, so they don’t meet the criterion of giving heat to outside air across the fins.