Turbocharger - Gasoline: Operation: Compressor
The compressor is connected directly to the turbine by a shaft; therefore, the speed of the turbine wheel will be the same as the compressor wheel. No exhaust gas is actually passed into the compressor. The spinning compressor forces more air into the intake manifold than would normally be drawn in under atmospheric pressure.
With a higher intake manifold pressure and denser charge available, more air/fuel mixture is drawn into the combustion chamber on the piston intake stroke. As the compressor spins faster, more air/fuel mixture is compressed into the manifold.