Centrifugal type supercharger
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The centrifugal type supercharger is practically identical in operation to a turbocharger, with the exception that instead of exhaust gases driving an impeller, there is only a compressor housing, and that is driven from the crankshaft via a drive belt. As such the centrifugal exhibits the same benefits and down-sides. Boost increases with the square of RPM (unlike the linear nature of the positive displacement devices), however low-rpm boost suffers due to the fact that air can pass back through the supercharger with little restriction until RPMs rise sufficiently to counteract the effect. Of all the belt-driven supercharger types this type exhibits the highest efficiency, and due to its design and lack of low-down boost is often employed on near standard compression engines. The Roots type supercharger and the twin-screw type supercharger, however, produce low-rpm boost and as such feel far more reactive on the road. The Volkswagen G60 cetrifugal supercharger was named after the G-Lader, a supercharger whose interior resembles the letter "G". The G60 engine was available in the VW Corrado but also in limited numbers in the VW Passat and the VW Golf. A similar, but smaller G40 equipped engine was available in the VW Polo during the early 90s. The 40 and 60 denoted 40mm and 60mm diameter charge exit pipes.
All supercharger types benefit from the use of an intercooler to reduce heat produced during compression.