Superchargers are like air compressors. Instead of drawing the gases from the car’s exhaust system they draw in fresh air and compress it before sending the air to the engine’s intake manifold. Superchargers in general aren’t able to produce as dramatic of power gains as turbochargers, but they don’t have a lag like turbos and they don’t struggle with heat issues. They also produce excellent power delivery at lower RPMs. Superchargers can produce an annoying whining noise when they’re operating. Depending on a supercharger’s setup, it can cause idle drop for the engine.

twin-charged engines utilize both a supercharger as well as a turbocharger. It is an older technology that is seeing a sort of resurgence in new cars. Current engine trends are leading automotive developers to revisit the idea of twin-charged engines to increase performance while keeping the engine compact and efficient. The best way to gain this performance is to force induction by way of either a supercharger or turbocharger. The problem is that each of them greatly increases both fuel consumption and emissions.

Each of these methods has its issues. Superchargers work well at lower RPMs but become far less fuel efficient at higher RPMs. Turbochargers seem to have an almost opposite problem of being more efficient at higher revs and less stable on the low end.

Twin-charged engines try to overcome these issues by running both kinds of forced induction systems in tandem. The supercharger takes responsibility for the low end where it is most effective, engaging from idle speed. It keeps spinning until it is within the effective operating range for the turbocharger to take over. The turbocharger then takes over at higher revs where it works best.

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