The driving force of the mechanical supercharger compressor from the engine crankshaft, usually use a belt connected to the crankshaft pulley, indirect crankshaft driven supercharger torque operation, to boost purpose. Depending on configuration, the supercharger will appear after many species, including blade (Vane), Roots (Roots), Winkle (Wankle) and other types, and the first movement of the piston is also considered a mechanical supercharger 2 Today, places Roots supercharger most widely used, it is converted favorite. Roots supercharger with a double leaf clover rotor two types, currently more common Futaba rotor, its structure is installed with two oval shell cocoon-shaped rotors, to maintain the minimum clearance between the rotor not directly connected by a helical gear linkage, wherein a rotor shaft and drive 318i Coilovers pulley link, equipped with an electromagnetic clutch pulley on the rotor shaft, that is when it is not pressurized to stop the release of the clutch booster, clutch by computer controlled to achieve fuel-efficient purpose.

Supercharged feature, in addition to the supercharger can be obtained at low speeds, the supercharger power output but also with a certain percentage of the crankshaft speed, that supercharged engine throttle response with increasing speed, the power output increase as , it feels supercharged engine operation and is very similar to natural gas, but it can have a greater horsepower and torque. Supercharged advantage of small size, without modifying the engine body, installed capacity, easily and is driven by a belt, the power does not have hysteresis, so the modified community also popular, again mechanically supercharged heat than the turbocharged Compared, but also has the advantage on the absolute, that is, heat exhaustion supercharged turbo engine 325i Coilovers does not have to serious, sustained and stable output is supercharged advantage, and therefore need to move often see long European vehicles, most still choose to supercharged as the main set.