supercharger

A supercharger is a device that increases the amount of air entering an internal combustion engine by compressing the intake air before it reaches the cylinders. By forcing more air into the engine, more fuel can be burned, producing more power. Unlike a turbocharger, a supercharger is driven directly by the engine, typically via a belt, shaft, or gears, so it provides boost continuously with engine speed. This creates immediate throttle response but consumes some of the engine’s power, creating a parasitic load.

There are several types of superchargers. Positive-displacement units, such as Roots and twin-screw (Lysholm) compressors, deliver a relatively constant boost at low to mid engine speeds and perform well for street driving. Centrifugal superchargers use an impeller to compress air and generally require higher engine RPM to produce substantial boost, often delivering peak pressure at higher speeds. Some designs are driven by mechanical linkages, while electric or hybrid systems use an electric motor to spin the compressor, potentially reducing lag.

Intercooling is commonly used with superchargers to cool the compressed air, increasing its density and reducing the risk of engine knock. In aviation history, superchargers were used to maintain engine power at altitude, and in automotive performance, they are favored for strong low-end torque and immediate power delivery.

Compared with turbochargers, which use exhaust gas energy, superchargers do not depend on exhaust flow and offer immediate boost but at the cost of extra engine parasitic loss. Applications range from production performance cars to racing and certain aircraft engines, with design choices balancing response, efficiency, and maximum power.