BMW SMG II / SMG III Sequential Manual Gearbox

BMW's Sequential M Gearbox (SMG) is an electro-hydraulically actuated 6-speed that provides paddle-shift gear changes in approximately 80 ms while retaining the mechanical efficiency of a conventional manual gearbox (unlike a torque-converter automatic). The E46 M3 used SMG II; the E60 M5 used SMG III (7-speed). Both systems use the same operating principle — hydraulic actuators replacing the manual clutch pedal and gear lever — giving M-division engineers the ability to offer the same total-loss mechanical efficiency of a manual with sub-100ms shift times previously reserved for racing.