SL to join AMG's Black Series Lineuip

By GREG KABLE

If you had any doubts that Mercedes-Benz intends to boost the sporting credentials of its facelifted SL roadster, you don't have to go any further than its upcoming SL65 AMG Black Series.

The two-seater is set to make its world debut at the German Grand Prix in July. Based on the SL65 AMG, the latest of AMG's Black Series models follows the route taken by the SLK55 AMG and CLK63 Black Series cars, with major changes to the mechanical package and bodywork--all aimed at boosting performance to a level that promises to see it challenge the 650-hp, supercharged 5.4-liter V8-powered McLaren-built SLR 722.

Details of the new Black Series car are scarce, though insiders indicate it gets a series of lightweight carbon-fiber panels and a fixed roof that brings additional rigidity to the body structure. Under the hood lurks a reworked version of the SL65 AMG's twin-turbocharged 6.0-liter V12 engine, tuned to deliver in the vicinity of 680 hp.

"We could have easily got 720 hp without any significant modifications. In the end, though, we decided to dial it back," said an insider privy to the new car's development.

Separately, Mercedes-Benz's AMG division is planning to add twin turbochargers to its 6.2-liter V8. However, the new development is not about raising power, according to well-placed AMG insiders. Rather, the addition of turbochargers will accompany the introduction of direct injection, helping to boost efficiency and lower fuel consumption.

"There will be a slight increase in power, but really it's all about creating optimal conditions for the introduction of direct injection," a source said.