Most of us understand supercharger boost, but what when a capacity is given in litres, what does it actually mean? The world has gone forced-induction crazy in the past few years. Dominated by the turbocharger, the entity of the supercharger has really struggled to keep up with the advances in technology and efficiency of the exhaust-driven turbine. On the contrary, they’re still embedded in American auto culture and therefore are still clinging on in this emissions and efficiency-obsessed world. But one aspect of superchargers that seems to sneak under the radar is their capacity or displacement rating. Normally only specced using boost figures, what does the actual volume of supercharger mean? As you may know, there are two main types of supercharger; centrifugal and positive displacement. In simple terms, a centrifugal supercharger is effectively a belt-driven turbocharger, resembling a turbine that is spooled up using the rotation of the belt connected to the crankshaft. The power delivery is non-linear due to the air being compressed by the centrifugal force of the compressor wheel which reaches speeds of tens of thousands of rpm. The connection to the crankshaft via the b...