Mercedes Benz

'Car and Driver' website got behind the wheel of the new SL 63 AMG, which was 'kind' enough to reveal its most intimate secrets. Scroll down to read the full review!Enjoy!

<< Mercedes’ luxury roadster gets more serious about sport.

At the Geneva auto show, Mercedes-Benz officials were stressing the company’s green aspirations ad nauseam—and then rolled out the latest AMG model, the 518-horsepower SL63 AMG. With a 6.2-liter V-8 engine underhood, this car is about as green as your average logging company.

The SL63 replaces the previous SL55 AMG, powered by a supercharged 5.4-liter V-8 that produced a mere 510 horsepower. The new car also features facelifted styling and interior revisions, plus a modified version of the company’s seven-speed transmission.

It certainly looks the part. The exterior changes that have been applied to all SL models make the car look more contemporary. The SL63 adds an aggressive front fascia and side skirts to signal its more sporting mien, plus standard 19-inch wheels and tires. Inside, there’s a special AMG steering wheel, gauge cluster, and shift lever to accompany other SL revisions that include an iPod interface and a Bluetooth phone hookup that both work pretty seamlessly.

Sophisticated Transmission

The most interesting feature of the car, however, is buried from view. Mercedes has decided to mate its conventional seven-speed planetary gearset with a multi-plate wet clutch (instead of the usual torque converter) to make the closest thing Mercedes has to an automated manual gearbox. Where BMW and Audi have gone the twin-clutch/twin-shaft gearbox route, the AMG engineers cite weight as one reason for this solution: a twin-clutch gearbox that could handle the SL63’s 465 pound-feet of torque would weigh at least 44 pounds more. The fact that Mercedes already builds its own planetary gearsets must have factored in, too.

The transmission has five modes, selected by a rotary dial next to the shift lever: standard (comfort); sport; sport plus; manual; and a launch control function. The sport and sport plus modes produce progressively faster shifts and heavier doses of revs while downshifting. The manual setting is self explanatory, allowing the driver control of the ratios via either the shift lever or steering-wheel-mounted paddles.

As with the previous SL55, Mercedes offers a Performance Package that features a more aggressive tuning of the Active Body Control (ABC) suspension system; a torque-sensing limited-slip differential; and bigger front brake rotors, up in diameter from an already monstrous 14.2 inches to 15.4. The package will likely cost about $14,000 on top of a projected base price of $133,000.

Luxury Cruiser and Serious Sports Car

The upshot of all these changes is a pretty special automobile that is both luxury cruiser and serious sports car. Leave the transmission setting alone, the stability control on (there are three modes), and the ABC in its comfort mode, and the SL63 will eat up highway miles quite serenely; the only clue to its more aggressive demeanor is a truly spectacular V-8 engine note that wouldn’t disgrace a NASCAR event. The transmission isn’t quite as smooth as a conventional automatic in town, but it is way better than the Sequential Manual Gearbox in the BMW M6.

Go aggressive on the ABC, transmission, and skid control settings, and the SL63 is a fast, satisfying back-road car. Nicely weighted, faithful steering is allied to good body control and a reasonably neutral chassis balance. On the track, you discover that 4350 pounds of automobile doesn’t respond well to attempts to brake and turn at the same time, when it will plow mightily, but it can be slid around like a much smaller sports car if one is patient on corner entry and uses the prodigious torque to unglue the 285/30 rear tires.

Fitted with the Performance Package, the SL becomes something of a track star, thanks to better body control, sharper turn-in, and even more powerful brakes. Using the launch control function, we predict a 0-to-60-mph sprint of about 4.2 seconds. Top speed is governed to 155 mph—the car gets there with alacrity and a soundtrack that is borderline illegal, along with whipcrack upshifts.

The SL63 isn’t as sporting as a Porsche 911 Turbo cabriolet, but it is a compelling alternative—and makes one wonder why anyone needs to spend half a million dollars on an SLR roadster, unless they just want to flaunt the amount of money they’ve got. >>

Head over to 'Car and Driver' for more info and images from the test