EXPERT’S GUIDE TO... SUPERCHARGERS
Forcing compressed air into a motor is an effective way of ramping up performance. But how does it work?
THE EXPERT Sean Mills The boss of Big CC Racing in Wokingham has been fitting superchargers since 2004 after he caught the turbo bug in the 1980s with a ‘crappy’ Suzuki XN85 and then a Kawasaki 750. Shoving compressed air into an engine is a sure-fire way of boosting the performance per cc, and there are two types of compressor available for doing such a task: turbochargers and superchargers.
A turbocharger uses the exhaust gases so there’s a certain amount of turbo-lag, but superchargers are different in that they use a mechanical drive via a gear, belt or shaft from the engine’s crankshaft.
A centrifugal supercharger is similar to a turbo as it compresses the air inside the supercharger case via an impeller, then discharges it into the motor and comes with a certain amount of lag.
But that’s a good thing. Imagine going around a mini roundabout at 3000rpm, then cracking open the throttle... you’d be sideways all the time. A centrifugal charger is more usable on a bike, precisely because it builds the boost progressively with the rpm of the engine. Typical power outputs are between 230-320bhp on forecourt fuel.
A centrifugal supercharger compresses air inside the case via an impeller