Turbocharger

A supercharger powered by an exhaust-driven turbine. Turbochargers always use centrifugal-flow compressors, which operate efficiently at the high rotational speeds produced by the exhaust turbine.

Boost Pressure

The increase above atmospheric pressure produced inside the intake manifold by a forced-induction system such as a turbocharger or supercharger. Boost is commonly measured in psi.

Turbo Lag

Within a turbocharger's operating range, lag is the delay between the instant a car's accelerator is depressed and the time the turbocharged engine develops a large fraction of the power available at that point in the engine's power curve.

Waste Gate

A valve used to limit the boost developed in a turbocharger. A waste gate operates by allowing some of the engine's exhaust flow to bypass the turbocharger's turbine section under certain conditions.

See also: Internal Combustion Engine, Naturally Aspirated, Supercharger.