There'll be a new, pretty quiet, exhaust note among the howling of high-revving engines and whistling of turbo waste gates at the 2006 Le Mans 24 Hours - a V12 diesel with so much torque the driver will hardly have to change gears.
The car was unveiled on December 13 in Paris and, if it succeeds at Le Mans, could hugely accelerate the demand for diesel-powered cars worldwide - perhaps even jolt the Americans into the modern world.
Racing diesel engines - even diesel racing vans - have been around for a while but none in the league of this superhighperformance block of aluminium from Audi: ultra-high fuel-injection pressures have helped take its output to around 500kW and, way more importantly, its torque to more than 1100Nm.
Now Audi is hungry for the first diesel-powered win at Le Mans - even though wins there are its forté. Audi first raced at Le Mans in 1999 and has won the annual sports car classic five times in the last six years with its Audi R8.
It will be interesting to see if Audi goes for a smaller fuel tank - because of diesel's better economy - and more speed or a larger tank and fewer pit stops.
Audi says the new 5.5-litre, 12-cylinder, twin-turbo TDI engine is extremely quiet and economical. It will have its race debut in the Sebring 12 Hours in the US in March, 2006 before lining up for the Le Mans start on June 17.
The Audi R8 sports car scored 61 wins from 77 races around the world but the German automaker is going into unexplored diesel-engine terrain with the R10.
As with its TFSI (turbo petrol direct injection) technology that triumphed at Le Mans before being adopted for mass-production, Audi customers should benefit once again from the lessons learned in motorsport.
Professor Martin Winterkorn, chairman of Audi's management board, said at the car's presentation in Paris:
"Audi already builds the A8 4.2 TDI quattro, one of the most powerful diesel cars in the world.
"The Le Mans project will help our technicians to extract even more from TDI technology. Today every second Audi is delivered with a TDI engine and we expect the percentage of diesel engines will become even larger."
Audi's current flagship, the Lamborghini-engined A8 S, uses a 5.2-litre V10 and all-wheel drive. It was launched at the 2005 Tokyo auto show.
The A8 4.2 TDI quattro, however is the top diesel.
The R10 prototype's V12 has two diesel particle filters and is so smooth-running it is hardly recognisable as a diesel but getting there presented Audi Sport engineers with many new challenges.
The injection pressure easily exceeds the 1600 bar achieved in production cars. The usable power band lies from 3000 through to 5000rpm - very low for a racing engine - and the driver needs far fewer gear changes than in the R8 because of the TDI engine's favourable torque curve.
Radical changes to the chassis were also necessary. The R10 has a significantly longer wheelbase than the R8. The unusually wide front tyres are unique on a Le Mans prototype.
The carbon-fibre monocoque chassis, the engine and gearbox form an extremely rigid, fully stressed unit that required the creation of new technologies during its development.
The head of Audi Motorsport, Dr Wolfgang Ullrich, explained: "The R10 was the biggest challenge yet for Audi Sport. TDI technology has not been pushed to its limits in motorsport yet so the demands of such a project are accordingly high.
"Long-term technology partners such as Bosch, Michelin and Shell are supporting us in our quest. Together we have the chance to write new chapters in the history books of motorsport and diesel technology."
- The R10 successfully completed its first test at the end of November but an extensive test programme is scheduled before the car's race début at Sebring.
The development team from Audi Sport is supported by Reinhold Joest's squad which also performed this task during the R8 project.