BMW 6-Speed Sequential Gearbox


The Z-Drive was a bespoke transmission designed for BMW Motorsport for use in their worldwide touring car program during the 90's. It was a 6-speed sequential unit, which featured magnesium cases and a special "Z" layout. This "Z" layout contained an input-shaft and an output-shaft with no direct 1:1 ratio, much like conventional Front-Wheel-Drive gearboxes. This is usually impossible in Rear-Wheel-Drive cars because of the need for the differential to turn clockwise. BMW however, designed a special anti-clockwise turning differential, allowing the lightweight "Z" transmission to work with just two-shafts and with it a far greater range of ratios, more efficiency and less heat.