BMW pulls a fast one

With a zero to 100km/h time of 5.1 seconds and a top speed of 250km/h, this four-seater is not for the faint-hearted, or follicularly challenged toupee wearer.

The six-speed manual convertible is expected to cost about $167,000 when it arrives in Australian showrooms in July.

BMW Australia spokesman Toni Andreevski says that, as with the M3 coupe, supply will be limited.

The hi-tech double clutch gearbox will be exclusive to the M3, he says. There are no plans to make it available on the M5 or M6.

“It's unlikely until the next-generation M5 and M6 cars arrive,” Andreevski says.

BMW Australia is also looking at the four-door M3 sedan.

But Andreevski says the company will monitor demand for the coupe and convertible before it commits to an M3 sedan.

“We've never sold an M3 sedan before,” he says. “But if we were to introduce it I'd say it would arrive early next year.”

Only the M3 convertible's doors, three-piece steel roof, boot lid, windows and rear lights are interchangeable with the 325i and 335i convertibles. Like the coupe, the convertible has a 4.0-litre V8 that develops 309kW at 8300 revs and 400Nm at 3900 revs.

Despite the extra weight of the stiff convertible, it is only 0.3 seconds slower to 100km/h.

The convertible returns a combined fuel-economy figure of 12.3 litres for 100km.

Visually, it shares the M3 coupe's striking grille, flared wheel arches, power dome bonnet, air-intake gills in the front side panels and 18-inch wheels.

At the back there is a rear air dam diffuser and dual M exhausts.

The 360mm front and 350mm rear brakes are lightweight vented, cross-drilled units designed to dissipate heat under heavy use.

The convertible's three-piece lightweight steel roof opens or retracts in 22 seconds and has extremely high standards of torsional stiffness and passenger safety. In the event of a rollover, two automatically activated rollbars pop up behind the rear seats.

The boot holds 350 litres of luggage with the roof up and 210 litres with the roof down.

As with the coupe, the convertible does not lack for equipment, which includes sun-reflective leather sports seats and aluminium highlights.

Double dealing

Thoroughness is a BMW engineering mantra. Not content to saddle its cars with a below-par, double-clutch gearbox, it set out to develop its own . . . specifically for a high-performance engine.

And that engine is the 309kW/400Nm 4.0-litre V8 in the M3.

Until now, double-clutch-style gearboxes have been restricted to small-capacity engines with moderate torque loads. BMW has designed its gearbox to deal with 9000 revs without complaint, yet maintain a consistent operating temperature.

Called the M double-clutch transmission with Drivelogic, it will arrive with the M3 convertible in July and subsequently be available on the M3 coupe. It will eventually replace the SMG sequential gearbox.

The gearbox uses two oil-cooled wet clutches that are individually responsible for different sets of gears. One clutch handles reverse, first, third, fifth and seventh gears, and the other the even ratios: second, fourth and sixth.

While driving, the transmission preselects the next gear, ensuring fast and smooth changes. The gearbox has 11 driver-selectable electronically controlled programs. These include five shift programs in the fully automatic mode and six in manual mode.

These are supplemented by a selectable “launch control” program that provides blistering acceleration from the 309kW V8.

An M3 coupe can now accelerate from zero to 100km/h in 4.6 seconds, 0.2 seconds faster than the manual six-speed. It returns an average fuel consumption of 11.9 litres for 100km.

Would you like to see the M3 sedan version in Australia?