What is it?

This is (postulates Porsche) the future of racing. The Porsche 918 RSR is based on the stunning 918 Spyder that debuted at Geneva 2010, though the differences are many and significant. The RSR is a hardtop, for a start, and instead of a full hybrid it's got a 'flywheel accumulator' linked to twin electric motors. Yes, once this car hits 88mph, it...

You'd think, right? Well, what it actually does is store energy captured during braking by the electric motor/generators - one at each front wheel. A pressed button will unleash the full electric fury from the accumulator - which spins to 36,000rpm - to the motors for a massive power boost; they generate 201bhp combined, which is added to the output of the RSR's 555bhp mid-mounted V8 petrol engine. Total: 756bhp.

Why's it here?

Porsche says it's here to show what can be done in the future with race cars - it's at "experimental level" in the company's words, but we wonder whether a more conventionally setup version will see Le Mans racing within a couple of years. The rest of the car looks ready to go, right down to the six-speed sequential gearbox and Michelin slick tyres.

Show stopper or floor filler?

Stop me! Like the Jaguar C-X75 at the Paris Motor Show, here's a car that matches traditionally stunning looks with some quite amazing future-gazing technology. Don't expect to see a flywheel accumulator on a passenger seat near you any time soon, but you never know...

Mark Nichol - 10 Jan 2011