Audi shows off new Le Mans racer

With Peugeot dropping out of this year's annual 24-Hour race around a middling French town called Le Mans, Audi were left without a dance partner. Luckily Toyota put on their dancing shoes and stepped in to tango with their awesome TS030 Hybrid which you HAVE to listen to here. And now Audi has shown their latest car, and it, too, is a hybrid. But a different kind of hybrid. A diesel-hybrid with four wheel-drive.

Christened the Audi R18 e-tron quattro, it's the lightest and most techy endurance prototype Audi Sport has ever built. The exciting part is that new quattro system, using the monster 510bhp from the torquey V6 TDI to power the rear wheels, and electric motors to power the front.

To understand how it works fully you need to own thick rimmed glasses, a white lab coat and a clipboard instead of an iPhone. But here's our attempt... It's not permanent four-wheel drive: the front axle only uses electric juice above speeds of 120km/h. This electric energy is sourced from kinetic energy that is dissipated during braking - which happens a lot at Le Mans. This is then recovered and fed as electric energy into a flywheel accumulator before being used to power the front wheels above those speeds of 120 km/h. Got it?

Adding all these hybrid parts adds weight to the car, so Audi went round trying to shave as many pounds as possible off last year's race winning R18. This included using a new gearbox with a carbon-fibre composite housing - another first for endurance racing.

"The new R18 ultra is a distinct evolution of last year's Le Mans race winning car," declares Head of Audi Motorsport Dr. Wolfgang Ullrich.

Audi Sport Team Joest will field two R18 e-tron quattro and two R18 ultra prototypes in the Le Mans 24 Hours on June 16/17, but the cars will both debut on May 5 in the 6-hour race at Spa-Francorchamps.

So what are you backing this year dot comrades? Toyota's petrol-electric hybrid? Or Audi's diesel-electric hybrid?