Supercharger and Boost (Blower)

A supercharger, nicknamed a blower, is a compressor that pushes more air into the engine than it could draw in on its own, so more fuel can be burned and more power produced. It is driven mechanically from the crankshaft. A turbocharger does the same job but is driven by exhaust gas.

Boost is the pressure the compressor adds above atmospheric pressure, measured in bar or kPa. More boost gives more power but also more heat and load, so engines need stronger internals and careful fuel and ignition mapping. A bike fitted with one is said to be blown.

Forced induction is rare on production motorcycles; the best-known example is the Kawasaki Ninja H2 family. Superchargers are also used in drag racing and on some high-performance jet skis.