Porsche 918 RSR. Click image to enlarge
Porsche 918 RSR
Detroit, Michigan – Porsche unveiled its newest hybrid racing car to the world in Detroit today. The fourth hybrid vehicle introduced by Porsche in the last twelve months, the world debut of the 918 RSR – the motorsports-oriented version of the 918 Spyder – merges technology of the 911 GT3 R hybrid with the design of the 918 Spyder.
The 918 RSR’s mid-mounted V8 engine is a development of the direct-injection engine from the successful RS Spyder race car. Two electric motors powering the front wheels each contribute 75 kW; leading to a peak power output of 767 hp from the hybrid system.
At the front axle, the two motors offer a torque-vectoring function to increase agility and improve steering response. Ahead of the rear axle, the mid-mounted engine is integrated with a racing transmission based on the RS Spyder. This six-speed constant-mesh transmission is operated using shift paddles behind the racing steering wheel.
Power generated during braking is stored in an optimized flywheel accumulator, an electric motor whose rotor rotates at up to 36,000 r.p.m. to store energy. Charging occurs when the electric motors on the front axle reverse their function during braking. When the driver needs additional power for acceleration or overtaking, the push of a button calls up the stored energy, deploying it in bursts of up to eight seconds when the system is fully charged.
As in the successful 911 GT3 R Hybrid, the additional power can also be used to reduce fuel consumption by lengthening the amount of time between pit stops.
The design of the 918 RSR builds on a tradition established by classic Porsche long-distance race cars such as the 908 long-tail coupé (1969) and the 917 short-tail coupé (1971). Its light, torsionally stiff monocoque body is constructed of carbon fibre-reinforced plastic (CFRP). It features doors which open obliquely, a roof-mounted air intake, quick-action locks on the front and rear lids, aerials for pit radio and telemetry, small front wings, splitters beneath the front lip and 19-inch slicks on centre-locking wheels.
Inside, a single, figure-hugging bucket seat faces a racing steering wheel and a recuperation display on the steering column, in front of a large display screen to supply the driver with information. Instead of a second seat, the flywheel accumulator is positioned to the right of the console.