Universal air-to-air intercooler with 16 rows — TA Technix

The turbo compresses air, and compression generates heat: at the compressor outlet, air can exceed 150 °C. It is then less dense, meaning it contains less oxygen, and causes knocking - which the ECU corrects by retarding the ignition, reducing power. The intercooler cools it before it enters the engine.

The benefit is therefore less about peak power than consistency: a saturated stock intercooler lets power drop sharply on the second lap of a circuit or during the third acceleration. Beware of the instinct to choose the biggest one: excessive volume takes longer to fill and blunts response. The right intercooler maintains temperature throughout your actual usage.