Brabus launches world's fastest four-seat convertible

Famous Mercedes-Benz tuner, Brabus, has revealed what it claims is the world's fastest and most powerful four-seat cabriolet at the weekend's 24 Hours of Le Mans.

Called the Brabus 850 6.0 Biturbo Cabrio, the new convertible shown at last weekend's endurance race is based on the Mercedes-AMG S63 4MATIC.

Claimed to generate an incredible 625kW/1450Nm from its twin-turbo 5.9-litre V8, the German tuner says its 850 Cab reaches 100km/h in 3.5sec , 200km/h in 9.4 and tops out at a limited 350km/h.

Brabus said the already incredible top speed is restricted over safety fears concerning the limitations of the 850's tyres.

To create the 850, the changes over the regular S63 have been exhaustive. The engine, for example, is a bored-out version of the standard car's 5461cc. Growing to 5912cc, the heavily modified twin-turbo V8 features a Brabus crankshaft with a longer stroke, forged pistons and high-performance connecting rods.

The old car's turbochargers were also binned for two larger Brabus compressors that are combined with two new exhaust manifolds.

Brabus also added a new stainless steel sports exhaust that incorporates a butterfly valve to add a quiet, or as the German tuner describes it, "coming home", mode.

As well as the internal changes, a new cold air intake system was developed. Indeed, to deal with considerable heat soak from the uprated engine, real gold reflective sheathing for the intake and charge-air pipes of the twin-turbo system were used.

Like the standard S63, the extra power is transferred to the wheels via Mercedes' 4MATIC all-wheel drive and seven-speed automatic transmission.

Brabus says it's added larger aluminium paddle shifters on the steering wheel.

Keeping the car stable at high speeds is a new aero package that includes a front spoiler, rear diffuser and fixed rear boot spoiler. All new aerodynamic-enhancing parts, as well as door mirrors and front bumper, have been created out of 'naked' carbon-fibre that saves weight and boosts rigidity.

Boosting grip is the addition of 255/35 front tyres and 295/30 21-inch wheel tyre combination that is claimed to be the "optimal" set-up. Brabus will also offer an even larger still 22-inch tyre and wheel package.

The company has also added a "lowering module" to the standard car's AIRMATIC air suspension to drop the ride height by around 15mm.

Inside, the tuning firm fits a speedo that now reads up to '400km/h' and switches any standard wood veneer interior parts for carbon-fibre.

Brabus claims the 850 can be sold to customers as a complete car or as a kit but has not yet released prices.