With six weeks to go to the Le Mans 24-hour race Audi has revealed more details of its R18 TDI racing car.
Changes to race regulations mean the V10 of the old R15 TDI has been replaced by a 3.7-litre V6 turbodiesel. According to Audi the new power plant brings with it a weight saving of 25 per cent allowing the company's engineers to explore a variety of options for electrification and energy recuperation.
To lower the centre of gravity and improve aerodynamics the cylinder heads on the V6 have been reversed, putting the exhausts in the centre of the V. The layout permits a simpler single exhaust system and a single turbocharger. It also allows air for the engine to be drawn directly from the air scoop on the roof of the R18.
Incidentally, Audi Sport claims that the R18 is its quietest ever car, producing a noise described as a whispering murmur.
Lessons from the R18 TDI's engine will be applied to future, road-going Audis.