BMW UK has announced details of the third M3 derivative, the new BMW M3 Convertible. The fourth generation of BMW’s open-topped M3 becomes the first M car to feature a Retractable Hard-Top. The launch of the new M3 Convertible also represents another first with the introduction of BMW’s new seven-speed M Double Clutch Transmission (M DCT) as an option to the standard six-speed manual gearbox.
Changing gear using either paddles on the steering wheel or the gear lever, the new M DCT gearbox uses two oil-cooled wet clutches, one controlling gears 1, 3, 5 and 7 and the other controlling gears 2, 4 and 6. With gear changes made in only a few milliseconds and the next gear selected in readiness, the M DCT-equipped car outperforms the manual gearbox car in outright performance, economy and emissions. The zero to 62 mph sprint is reduced by 0.2 seconds to 5.1 seconds while the combined consumption improves by 1.1 mpg and the CO2 emissions decrease by 16 g/km to 293 g/km.
Developed with Getrag (model DCT436), the new M DCT gearbox also features Drivelogic to allow the driver the ability to fine tune the shift characteristics of the transmission. With six shift speeds available in the manual mode and five available when the gearbox is pre-selecting its own ratio, the driver can fine-tune the gear change. And to ensure that the gear changes are perfectly tuned to the engine output, the new M DCT gearbox employs eight LED shift lights, located in the rev counter, to warn the driver of the need to upshift.
Finally, to guarantee ease of use in around-town driving situations, the new M DCT gearbox uses a gradient detection system and Low Speed Assistant. These combine to ensure that the car won’t roll back on hill-starts and that the engine’s high levels of output don’t corrupt the driving experience at slower speeds.
See our document Double clutch transmissions.
Yvonnick Gazeau
