Mercedes goes from ragtop to riches

MERCEDES-BENZ has officially revealed the SLS AMG Roadster – the convertible version of AMG’s awesome gullwing-bodied coupe – and confirmed it will be launched in Australia in the first quarter of 2012.

The coupe was the first car produced from the ground up by Mercedes-AMG GmbH and the roadster version was designed and developed in parallel, although it has taken almost two years longer to make it into production.

Mercedes this week confirmed technical specifications for the car, with coupe-matching power and torque figures of 420kW and 650Nm from its hand-built 6.2-litre V8 engine.

Carrying a modest extra 40kg of weight over the gullwing model, the Roadster will still sprint from rest to 100km/h in just 3.8 seconds – the same as the Coupe.

Early this month, Mercedes released test and development photos of the SLS AMG Roadster without badging, but these photos reveal the first production-ready cars ahead of their public debut at the Frankfurt motor show on September 13.

Eschewing the current fad for folding metal hardtops, the new Mercedes flagship instead employs a folding three-piece soft-top that is lighter and produces a lower centre of gravity for the benefit of performance and handling.

Mercedes confirmed that the fabric roof opens or closes – at the push of a button integrated into the front of the centre console – in just 11 seconds, even with the vehicle travelling at up to 50km/h, matching some of the best convertibles in the world.

The roof folds away in a Z configuration behind the two occupants, reducing boot space by just three litres over the coupe (173 versus 176 litres).

Available in black, red and beige, the three-layered fabric top has a frame made from magnesium, steel and aluminium to keep the weight and centre of gravity low, while the single-layer rear window is bonded into place and heated.

Mercedes-AMG claims there is a flush, gap-free transition between the outer roof skin and the rear window to keep wind noise to a minimum while a continuous, flexible water pocket running under the soft top catches rainwater and directs it to the underbody via two apertures on each side.

Safety features include automatic (and leather-lined) roll-over bars to protect the occupants in the event of the car flipping, and eight airbags – adaptive front and kneebags, seat-integrated side airbags and a pair of windowbags that deploy from the doors.

Of course, the seats in Australian-spec models – in keeping with a pricetag expected to exceed $500,000 – will feature Mercedes’ now-familiar Airscarf system, which blows warm air from adjustable vents in the head restraints around the head and neck.

Other standard features include a glass wind-blocker, black leather interior, heated sports seats, an entertainment system with DVD player, keyless entry and start, an alarm system and automatic climate control.

Matching a new metallic brown paint finish is an optional single-tone or two-tone espresso brown leather trim.

Announced as an option in Europe is a new motor racing-inspired telemetry system called AMG Performance Media that also provides high-speed mobile internet access.

AMG Performance Media provides real-time display of engine oil, coolant and transmission fluid temperatures, engine output, torque and accelerator position, individual tyre pressures, 0-100 km/h or quarter-mile acceleration times, lateral and linear acceleration combined with braking performance and accelerator position, and individual lap times, including sector times and memory function.

The different functions are shown by the colour display integrated into the dashboard, with three displays shown at any one time, the centre one showing the most important information.

Mechanically, the Roadster matches the Coupe with its normally aspirated V8 engine, seven-speed dual-clutch transmission, lightweight aluminium spaceframe and aluminium double-wishbone suspension with three-mode automatic ride control. It is electronically limited to a top speed of 317km/h and has official European environmental figures of 13.2L/100km fuel consumption and 308g/km emissions.

Sitting on 10-spoke matte-black 19-inch front rims and 20-inch rears – wearing 265/35 and 295/30 ZR rubber – the SLS AMG Roadster weighs just 1660kg despite being designed with additional bracing to ensure a rigid structure without the benefit of a roof.

According to Mercedes-AMG, the convertible achieves the same level of driving dynamics as the coupe despite the lack of a fixed roof, thanks to thicker side skirts with more chambers, additional struts to support the dashboard cross-member against the windscreen frame and centre tunnel, a curved strut between the soft top and the tank that reinforces the rear axle, and a reinforcing crossmember behind the seats to support the roll-over protection system and the 250 watt subwoofer of the high-end Bang & Olufsen sound system.

Engineers say these measures prevented unwanted vibrations, making it unnecessary to use the additional, weight-increasing vibration dampers often found in open-top sports cars.

Mercedes-AMG chairman Ola Kallenius said the SLS Roadster is a super-sportscar, cruiser and highly desirable dream-car all in one, highlighted by cutting-edge engineering.

“Systematic lightweight construction, outstanding performance and a breathtaking design combined with sensuous open-air driving pleasure – the new SLS AMG Roadster perfectly embodies the AMG philosophy of German engineering and craftsmanship,” he said.

“The gullwing model has already thrilled sportscar fans all over the world and now the open-top version is bound to cause a sensation.”