Roots type supercharger

The Roots type supercharger is a positive displacement type device that operates by pulling air through a pair of meshing lobes not dissimilar to a set of stretched gears. Air is trapped in pockets between the lobes and carried between the intake side to the exhaust. The supercharger is typically driven directly from the engines crankshaft via a belt. In order for the supercharger to deliver air at greater pressure than atmospheric, the Roots supercharger must be geared so that it turns faster than the engine. Out of the three basic supercharger types the Roots is considered the least efficient. However, it is also widely used and thus is invariably the most cost efficient. Much work has been done to improve the efficiency of the Roots type supercharger, but because it does not have internal compression it will never have the same potential as the twin-screw type supercharger, or the centrifugal type supercharger.

All supercharger types benefit from the use of an intercooler to reduce heat produced during compression.