A unique BMW M5 CSL has been unveiled. This one-off unit features a 5.5 V10, carbon fibre roof and a 7-speed double clutch transmission.

A one-off BMW M5 CSL was unveiled at the company's Nurburgring workshop. The prototype is a unique M Division example that forms part of the M5 brand's 25th anniversary celebrations.

The big news is the engine which was modified from the factory 5.0-litre V10 to a larger 5.5-litres via increased stroke, making it M Division's largest ever. Modifications include a carbon fibre manifold with an increased capacity air box and secondary oil cooler. As a result another air duct was created on the front bumper to accommodate it.

One way to qualify as a CSL (Coupe Sport Lightweight) is to shed body mass, which this one did. A carbon fibre roof was employed and some interior parts stripped down. For example standard front seats were replaced with carbon fibre units and the rear one removed completely. A total weight saving of 50kg was achieved. The suspension was also slightly modified but kept close to standard.

Long-time BMW race driver Claudia Huertgen has taken the car around the ‘Ring and claims to have posted a sub-8 minute time.

Official figures were not released but M division's head of development, Albert Biermann told Autocar that something around 580bhp (433kW) and 400 lb-ft (542Nm) could be expected. It is sent to the rear wheels via the double clutch M-DCT 7-speed gearbox. The power figure sounds close to what is speculated for the next-generation car.

"Right now we're concentrating on the next-generation M5," Biermann said. "This car has been fun to develop but there are no plans for production."

NOTE: BMW M5 Ring Taxi at Nürburgring's Nordschleife pictured.  Photos to be updated later.


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