Lamborghini Unveils 819-hp Topless Hypercar

Lamborghini announces the Sian Roadster, a convertible version of what the Italian automaker says is the most powerful model it has ever produced.

The Sian (pronounced SHAHN, “flash of lightning” in local Bolognese dialect) is powered by a hybrid system comprising Lamborghini’s next-generation 785-hp V-12 and 48V electric motor generating 34 hp, for a combined 819 hp.

With a weight-to-power ratio of just 2.0 kg/hp, the hybrid reaches 97 mph (100 km/h) in under 2.9 seconds and its top speed exceeds 217 mph (350 km/h), Lamborghini says.

The automaker planned to build just 63 Sian models following the hypercar’s introduction at the 2019 Frankfurt auto show. Only 19 convertibles have been built and all have been sold.

“Sian’s innovative hybrid powertrain heralds the direction for Lamborghini super sports cars, and the open-top Sian Roadster affirms a desire for the ultimate lifestyle Lamborghini as we move towards a tomorrow demanding new solutions,” Lamborghini Chairman and CEO Stefano Domenicali says.

The Sian Roadster’s electric system features supercapacitor technology that stores 10 times the power of a lithium-ion battery. The system is three times more powerful than a battery of the same weight and, at 75 lbs. (34 kg), is three times lighter than a battery producing the same power, Lamborghini says.

Symmetric power flow ensures the same efficiency in both charging and discharging cycles.

The supercapacitor also varies from Li-ion batteries by charging and discharging with the same power, fully charging the Sian Roadster’s energy-storage system every time the vehicle brakes. The stored energy is an instantly available power boost that increases torque when accelerating, up to 78 mph (130 km/h) when the electric motor automatically disconnects.

Airflow is directed through the front splitters and hood, through the side intakes and outlets and over the rear spoiler with no loss of aerodynamic efficiency from the roadster's roofless design. The rear wing is integrated within the profile and extends only during driving.