During the test day of the 24 Hours of Le Mans, the R18 has shown that it is possible to reduce engine capacity without sacrificing performance. What are the secrets of Audi downsizing?

The new regulation requires the use of smaller engines than in previous years. Audi has opted for a 3.7-litre V6, about 25% lighter than the V10 TDI fitted to the old R15 (see picture of V6). According to its designers, the architecture of the new block offers more room for future implantation of a KERS. "We are very interested in these systems," explains Wolfgang Ullrich Head of Audi Motorsport. "Once this technology is proven to be effective, we will use at Le Mans. "

The angle of the V very open (120 °), used by Renault F1 between 2001 and 2003, effectively lowering the centre of gravity of the engine. The space freed up between the two cylinder banks can accommodate the exhaust manifold, more usually positioned on the sides of the engine.

The Audi R18 has placed a turbocharger, too, in the centre of the V and supplied with air via a duct visible on the roof. Using a single turbo is made possible only thanks to its variable geometry. "Otherwise, the response time would be just too bad, "says Ulrich Baretzky chief engineer. The exhaust gases are, in turn are discharged through a single pipe that leads to the rear pylon under the wing.

Julien Hergault - According to the communique of Audi Motorsport

Photo: Mans (Sarthe), DAY OF TEST LE MANS 24 HOURS, 24 April 2011. With an engine delivering "only" 540 horsepower, the Audi R18 has managed to cover 13,629m of the circuit in less than 3'30 "!