THE seven-speed dual-clutch automated manual transmission that made its debut in the storming M3 coupe has now filtered down to more modest versions of BMW's 3 Series.
BMW Australia has announced the new double-clutch transmission (DCT) will replace the six-speed Steptronic automatic in the 335i Coupe and 335i Convertible from this December.
The new gearbox, which is similar in operation to the Volkswagen Group’s DSG transmission, will be available as a $3500 option.
BMW said the dual-clutch automatic allows the 335i Coupe to dash to 100km/h in 5.4 seconds, 0.3 seconds faster than when it ran the Steptronic.
Its own testing suggests the DCT-equipped auto is also faster to 100km/h than the six-speed manual - by 0.1 seconds.
The official fuel consumption figure of the 335i Coupe with the new seven-speed auto is 9.1 litres per 100km, which represents a saving of 0.4L/100km over the outgoing auto and the current six-speed manual.
The new transmission has been tuned especially for the twin-turbo 335i Coupe and Convertible in order to manage its 225kW and 400Nm of torque.
A dual-clutch automatic such as that used by BMW and Volkswagen can shift more quickly and therefore more efficiently than both conventional manual and automatic transmissions because it is split into two halves and has a second clutch that pre-engages the next gear before the driver selects it.
Widely billed as offering the best attirbutes of both manual and automatic transmissions, the transmission can be controlled with a shifter mounted on the centre console or by using steering wheel-mounted paddles.