 A mechanically-driven supercharger offers exceptional response and low-rpm performance as it does not rely on pressurization of the exhaust manifold (assuming that it is a positive-displacement supercharger such as a Roots type or twin-screw and not a Centrifugal compressor supercharger, which does not provide substantial boost in the lower RPM range).A turbocharger sized to move a large volume of air tends to respond slowly to throttle input while a smaller, faster-responding turbo may fail to deliver sufficient volume through an engine's upper RPM range.The unacceptable lag time endemic to a large turbocharger is effectively neutralized when combined with a supercharger which tends to generate substantial boost pressure much faster in response to throttle input.