There’s more to this hardcore SL than a special-edition version of Mercedes elegant cabriolet. Underneath the beefed-up body, with ts huge wheelarch extensions and new front end, lie the building blocks for Mercedes’ top-secret new supercar, codenamed W197.
This car, due late next year, even shares the forthcoming supercar’s name – SLC. Effectively a Black Series version of the SL, it will be based on the facelifted SL out in March 2008, with that car’s new headlamps, grille and LED tail lights.
In addition to these upgrades will be the wide front bumper seen on this development car, wider sills and a big boot spoiler. And the SLC will have a fixed roof made of carbonfibre, replacing the SL’s folding metal lid.
The new car’s development is being led by AMG in conjunction with HWA, the company responsible for Mercedes’ DTM (German touring car) programme and supplier of carbonfibre to the company. HWA is also heavily involved with the W197 project.
Underneath this test car are components that will be used on the W197, such as the rear axle. A highly-placed AMG source said that the SLC will be a purist’s machine; the suspension will be steel springs not air, and Mercedes’ electronic driver aids, such as Active Body Control, won’t be fitted. Adjustable springs and ride height are likely options.
Secrecy surrounds the engine. Early indications from AMG’s works on the outskirts of Stuttgart suggested the car was in line to receive a reworked version of the company’s naturally aspirated 6.2-litre V8 with lightweight internals and a higher compression ratio, permitting it to rev to around 8200rpm and with over 600bhp.
However, Autocar understands Mercedes has reversed an earlier decision to discontinue development of a twin-turbo 6.0-litre V8 and that the SLC will receive this engine.
The new engine is based on Mercedes’ existing 5.5-litre V8, and is being engineered under Friedrich Eichler – the man responsible for the Porsche Carrera GT’s 5.7-litre V10.
Transmission is likely to be a seven-speed auto, if AMG’s engineer’s can modify it to handle the engine’s torque and power, likely to be around 700bhp and 740lb ft.