The ______ removes heat from the incoming air charge, before it enters the engine.

• A. Turbocharger
• B. Throttle body
• C. MAF sensor
• D. Intercooler

Answer: (D)

When air is compressed by a turbocharger, its temperature rises. An intercooler acts as a heat exchanger that removes that heat from the compressed air before it enters the engine. Cooling the air makes it denser, so more oxygen is available for combustion, which can boost power and help prevent knocking under boost. Different types exist, such as air-to-air or air-to-water intercoolers, and they sit in the intake path between the compressor and the intake manifold.

The other components don’t perform this cooling role: a turbocharger increases pressure but not cooling; the throttle body mainly controls how much air can flow into the engine; the MAF sensor measures the amount of air, rather than cooling it.