M3 double-clutches

At its Australian launch in October 2007, BMW's new V8 M3 coupe only came with a manual six-speed gearbox.

Considering the outgoing six-cylinder M3 was also available with an optional sequential-manual SMG gearbox, this left a significant gap in the options list.

But BMW hasn't wasted any time correcting that with the announcement in overseas markets that the six-speed manual M3 is now joined by an all-new seven-speed sequential manual option -- complete with VW-Audi style double-clutch operation.

A much more refined system than the SMG transmission available in the previous six-cylinder M3, the new gearbox is lengthily described by BMW as the M double-clutch transmission with Drivelogic.

It uses separate clutches that are individually responsible for different sets of gears -- one for the odd ratios, including reverse, one for the even ratios.

Because the next ratio prior to a gearshift is always in mesh, the actual gearshift is a matter of the clutch actuating the upchange. BMW says shifting from one ratio to the next is, apart from the change in engine rpm, virtually imperceptible.

The new transmission offers up to eleven programs, via full-auto (five programs) and manual (six programs) modes, modifying both the speed and nature of the gearshift according to what the driver wants at the time.

In the maxi-sport mode -- S6 -- the driver also has access to a launch control program that regulates the transmission of power for super-fast takeoffs.

The result, according to BMW, is a faster M3 with the new gearbox -- and more economical and cleaner at the exhaust -- than regular six-speed manual versions.

The zero to 100km/h time -- in M3 coupe form -- is 4.6 seconds, compared to 4.8 seconds for the conventional manual, and the combined cycle fuel economy figure is 11.9L/100km.

The new transmission also comes with a "Low Speed Assistant" mode that helps remove the jerkiness that afflicts most SMG-style transmissions when creeping along at low speeds, as well as gradient detection that works on eliminating "hunting" between ratios in full-auto mode on undulating roads.

The driver is able to shift manually via a central console lever, or steering wheel paddles.

The new transmission option was announced on overseas markets alongside the introduction of the hardtop convertible version of the M3.

Australia is expected to see the new transmission in July this year, at the same time as the local introduction of the M3 convertible. The M3 sedan currently on sale on other world markets is also expected to come here, but not until early 2009.

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