Mercedes-AMG SL plug-in hybrid arrives with more than 800bhp

Mercedes-AMG has unveiled the SL 63 S E Performance as the first hybrid version of its drop-top grand tourer - and the most powerful variant yet.

It's the fifth plug-in hybrid from the AMG performance division and will be one of the fastest convertibles on sale when it lands next year. 

It gets broadly the same powertrain set-up as the GT 63 S E Performance and S63 E Performance saloons. Power comes from a 4.0-litre twin-turbocharged V8 that produces 603bhp on its own. This is paired with a 201bhp electric motor mounted at the rear for a combined output of 804bhp and that jaw-dropping 1047lb ft torque figure.

As a result, it gets a McLaren 750S-baiting 0-62mph time of 2.9sec and a top speed of 196mph, making it only slightly slower than the Ferrari 296 GTS and Porsche 911 Turbo S Cabriolet.

Stopping power comes from carbon-ceramic brakes clamped by bronze-coloured callipers specific to the PHEV. 

AMG CEO Michael Schiebe said: "With this unique concept, we offer our customers not only superior performance but also the option of all-electric driving.

"Extensive equipment options and the high-quality materials used also make the SL one of the most exclusive roadsters on the market - a real dream car."

The motor is attached directly to the rear axle and works to boost power under acceleration, when overtaking and getting off the line.

It's connected to a two-speed gearbox that works with the seven-speed automatic gearbox mated to the engine and can send its power to the front wheels when the rears begin to lose grip - a hallmark of the German brand's P3 performance powertrain.

The car also has rear-axle steering as standard to aid both low- and high-speed manoeuvrability. 

To aid grip in high-demand situations, a mechanical limited-slip differential is attached to the back axle, above which is mounted a "lightweight, high-performance" 400V battery developed with know-how from the Mercedes-AMG Formula 1 team.

The battery is said to provide a continuous and reliable delivery of performance in high-demand situations, with particular attention paid to improved cooling. It allows the car to travel eight miles on electricity alone but wasn't developed to provide "the longest possible range". 

The driver can choose between eight driving modes: Electric, Battery Hold, Comfort, Smoothness, Sport, Sport Plus, Race and Individual. Each one adapts throttle response, gearchange ferocity, steering weight, sound and chassis damping.

Up to four levels of energy regeneration are available in each mode, allowing more than 100kW of power to be fed back into the battery.

When the car starts, it will be under electric power only, but inside the driver will hear a synthetic sound that mimics the V8 engine. 

In its design, the car remains broadly the same as the standard SL 63 AMG but gains a charging flap on the rear bumper and red 'E Performance' badging on the boot and front fenders.

The PHEV also gets bespoke, aerodynamically optimised alloy wheels of 20in or 21in in diameter.

More aerodynamic touches can be found in the form of a carbonfibre front splitter, which extends downwards by 40mm at speeds above 50mph, and a ducktail rear spoiler that deploys at the same speed.