The Lamborghini Sian Roadster is powered by an uprated version of the Aventador’s naturally 6.5-litre V12 producing 785hp combined with a 35hp 48V electric motor integrated into the gearbox for zero-emission low-speed manoeuvres.
The electric motor is also used to flatted the Sian’s acceleration curve, kicking in to provide toque fill that mitigates the effects of deceleration during gear changes. Lamborghini says is that “the pilot will feel only the pull backward of acceleration, eliminating uncomfortable jerking movements’
As a result, the Sian Roadster is claimed to sprint from 0-100kph in just 2.9sec and will hit a top speed of 390kph. A weight of 1650kg is claimed.
Lamborghini claims that the addition of an electric element to the V12 motor has not affected the powertrain’s trademark sound.
Both versions of the Sian 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 boost at will while travelling at speeds up to 130kph.
The device evolved from that used to power the Aventador’s starter motor, weighs just 35kg. This results in a power-to-weight ratio of 1hp per 1kg and ensuring minimal impact on performance. Symmetric power flow means it changes using the energy recovered under braking at the same rate as discharging, providing maximum efficiency.
The Sian’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 included are heat-sensitive cooling vanes on the rear deck that rotate spoiler that sits flush with the engine lid while the car is stationary. According to Lamborghini, removing the roof has no effect on the aerodynamic efficiency of Sian.