DCT is transmission of choice for quickest BMW Z4
The seven-speed dual clutch transmission already seen on BMW's 3-series models has been selected as the optional system on the top models of the company's relaunched Z4 two-seater roadster.
The transmission, supplied by Getrag, will go into the most powerful twin-turbo 3.0 liter versions of the Z4, labeled Z4 sDrive35i. The two lower-powered editions of the Z4 get a six-speed Sport Automatic planetary auto as their option; a six speed manual is the standard transmission across all three lines.
With a power output of 306 hp at 5800 rpm and torque of 400Nm between 1300 and 5000rpm, the top sDrive35i accelerates to 100km/h (62mph) from rest in 5.2 seconds with the standard six-speed manual transmission: with the seven-speed DCT the time is cut to 5.1 seconds. Efficiency is likewise improved by the DCT when it comes to fuel consumption and emissions: the manual car records 9.4lit/100km (24.1 US mpg) and 219 grams per kilometer CO2 emissions, as against 25.1mpg and 210g/km for the DCT version.
With the advent of the new-look Z4, with its revised exterior, fresh interior and rigid folding roof system, manufacturing relocates from Spartanburg in North Carolina to Germany. Taking the place of the Z4 in the US plant is the X6 sports activity model.
Inclusion of the Getrag transmission option on the new Z4 brings the list of BMW models available with double clutch transmissions to three. First was the high-powered M3 sports coupé with its V8 engine, followed by a different version of the transmission on the 335i Coupe and Cabrio versions of the 3-series.
Story Filed: 5/8/2009
By Tony Lewin, managing editor DCTfacts.com