808bhp Lamborghini Sian roadster is world’s most powerful open-top production car 

The new Roadster version of Lamborghini’s Sián hybrid hypercar is the most powerful open-top production car in the world, its 808bhp output usurping the 780bhp Ferrari 812 GTS. 

Just 19 examples of the Sián Roadster will be built – making it much more exclusive than the series-produced Ferrari - and all have been sold already. 

Like the striking hard-top Sian revealed at last year’s Frankfurt motor show, the Roadster takes the bulk of its power – some 774bhp – from an uprated version of the Aventador’s naturally aspirated 6.5-litre V12 and features a 34bhp 48V electric motor integrated into the gearbox for zero-emission low-speed manoeuvres. 

The electric motor is also used to flatten the Sián’s acceleration curve, kicking in to provide torque fill that mitigates the effects of deceleration during gearchanges. An added benefit of this, Lamborghini says, is that “the pilot will feel only the pull backward of acceleration, eliminating uncomfortable jerking movements”.

As a result, the Sián Roadster is claimed to dispatch the 0-62mph sprint quicker than the conventionally powered Aventador SVJ Roadster’s 2.9sec and its top speed is pegged at more than 217mph. A weight figure of under 1650kg is claimed, although we have no indication yet of how much heavier the hard-top is for comparison.

At the reveal of the hard-top, Lamborghini claimed that the addition of an electric element to the V12 motor has not affected the powertrain’s trademark sound. 

Both versions of the Sián can call upon a supercapacitor power storage unit - said to store 10 times more power than a conventional lithium ion battery - to provide instant torque boosts at will while travelling at speeds of up to 81mph. 

The device, evolved from that used to power the Aventador’s starter motor, weighs just 34kg, giving a power-to-weight ratio of 1bhp per 1kg and ensuring minimal impact on performance. Symmetric power flow means it charges using energy recovered under braking at the same rate as discharging, providing maximum efficiency.

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The Sián’s trademark design features are carried over unaltered, including the six Countach-inspired brake lights, hexagonal exhaust exits, Y-shaped headlights and gaping air intakes at the front and side. 

Also featured are heat-sensitive cooling vanes on the rear deck that rotate according to the engine temperature, aerodynamic ‘airstreamers’ at the rear and a retractable spoiler that sits flush with the engine lid while the car is stationary. According to Lamborghini, removing the roof has had no effect on the Sián’s aerodynamic efficiency.

Each of the 19 examples sold will be built to the owner’s desired specification by Lamborghini’s Ad Personam personalisation arm, with the option to choose from a range of exterior and interior colours and finishes, and even have the 3D-printed air vents inscribed with the owner’s initials. 

'Sián' translates to ‘flash’ or ‘lightning’ in English and Lamborghini is using the Sián duo to set the tone for its upcoming electric era. CEO Stefano Domenicali said: “The Sián’s innovative hybrid powertrain heralds the direction for Lamborghini super-sports cars, and the open-top Sián Roadster affirms a desire for the ultimate lifestyle Lamborghini as we move towards a tomorrow demanding electrification.”

Unlike the Sián hard-top, the Roadster has been revealed at a stand-alone event. Lamborghini recently announced its intention to stop attending motor shows and will focus instead on providing the “exclusivity, personalisation and one-to one contact” it says its customers want.