Lamborghini has debuted its most powerful and fastest-accelerating car at the Frankfurt motor show, and it’s also the firm’s first hybrid. The limited-run Sian previews Lamborghini’s plans to take its brand of V12-powered flamboyance into the near future with models such as the next-generation Aventador.

The Sian features the Aventador SVJ’s naturally aspirated 6.5-litre 12-cylinder unit, but it has been uprated from 770 to 785hp with the addition of titanium intake valves, and is mated to a 48V electric motor producing 35hp, for a combined total output of 820hp. In what Lamborghini claims is a first for low-voltage hybrid powertrains, the electric motor is integrated into the gearbox and connected to the wheels for low-speed reversing and parking manoeuvres. The charismatic sound of the V12, Lamborghini assures, has been preserved.

The developments mean the Sian will offer enhanced acceleration over Lamborghini's conventionally fuelled models, sprinting from 0-100kph in under 2.8sec, with top speed claimed to be in excess of the SVJ’s 349kph.

Power is not stored in a conventional lithium-ion battery, but rather generated by a supercapacitor unit that’s three times as powerful as a cell of the same weight, and three times lighter than a battery with the same output. The device, mounted ahead of the engine for enhanced weight distribution, is an evolution of that found in the Aventador to power the starter motor, and can store 10 times as much power as the original.

A regenerative braking system, developed in-house, sends power to the supercapacitor unit under deceleration. Energy generated in this way is available as a power boost at the discretion of the driver at speeds of up to 130kph.

The electric motor also allows for a smoother acceleration curve, activating during gear changes to counter the effect of deceleration and resulting in a 70-120kph time that’s 1.2sec quicker than that of the SVJ. Traction at lower speeds is improved as well, making the Sian 10 percent faster than a car without this system, according to its maker.

The Sian’s wedge-shaped silhouette is characteristically angular and wide, and is said to be influenced by the work of Bertone’s Marcello Gandini, who was responsible for some of Lamborghini’s best known historic models.

The diagonal lines along the length of the bonnet, six hexagonal tail-lights and roof-mounted ‘periscope’ tunnel are a nod to the Countach, while the low front splitter and Y-shape headlights are a setup originally intended for the electric Terzo Millenio concept.

Downforce is maximised by the model’s prominent side air intakes and large carbon-fibre front splitter. In keeping with the Sian’s “pure and uncluttered” design ethos, the rear wing sits flush with the rear deck, extending only at speed, while active cooling vanes along the engine lid react to exhaust temperatures and rotate as needed.

Lamborghini will make just 63 Sians (all have been sold already), offering buyers a high level of personalisation through its bespoke Ad Personam division.