Audi was out of sports car racing and Le Mans as a factory team after 2002, following their third win with the Audi R8 prototype. After supplying R8 prototypes to partner teams in 2003, 2004 and 2005, Audi made their official comeback in 2006 with the new R10 TDI open-top prototype. Audi was the first big manufacturer which tried to run at Le Mans with a diesel-powered car. That means, the company had serious plans for its car and the big money was spent for development of R10 TDI.
The engine of a choice was the 5.5-litre V12 TDI engine. It has two parallel turbochargers and utilizes the Turbocharged Direct Injection (TDI) technology. The engine block was made of aluminium, employing common rail direct fuel injection technology. The turbochargers were supplied by Garrett, with 39.9 mm restrictor plates mounted. Audi’s V12 was officially producing about 650 hp, up to 700 hp in qualifying-mode. There was also a possibility of short-term overboost, with additional 150 hp for overtaking.
Audi engineers had to solve a possible problem with the engine’s weight of more than 200 kilos. The wheelbase of a new car was increased over the R8 to accommodate the longer engine. The open-cockpit R10 was similar to R8, but many design details and aerodynamics were different. The monocoque chassis was built 90% by Audi and 10% by Dallara as well with various suppliers manufacturing all the components and subassemblies. The cars are then assembled by Audi at Ingolstadt factory.
The R10 Tdi made his debut in the 12 hours of Sebring 2006. With Capello, Kristensen and A. McNish at the wheel, they won their first race. The Audi team would eventually dominate the whole 2006 ALMS championship.
“At Sebring, we saw how complex an engine change can be,” Ralf Jüttner, Team Director of Audi Sport Team Joest, recalls. “That’s why we decided not to change the engine before the race – as usual – but to use the same power-plant in all practice and qualifying sessions, as well as in the 24-hour race.” As a result, it was necessary to drive as few kilometers as possible in the practice and qualifying sessions. Setting up a new race car for the Le Mans track under these circumstances posed a major challenge
In the 24 hours of Le Mans 2006, Audi entered two cars. The drivers in the #7 were Tom Kristensen, Rinaldo Capello and Allan McNish. The #8 was driven by Frank Biela, Emanuele Pirro and Marco Werner.
The Audi R10 TDIs were by far the fastest and most economical cars. The diesel engine resulted in fewer refuelling stops and fewer gear changes. It was also the quietest car on the track.During the entire race, one was always at the head of the field. Le Mans record winner Tom Kristensen drove the fastest lap of the race, setting a 3m 31.211s time, and he was the first driver at the wheel of an LM P1 sportscar to cover 16 laps with one fuel load. Completing 380 laps, Audi car #8 also set a new distance record.
While car number ‘7’ suffered a few setbacks in the race( and finished third), the subsequent winning car, number ‘8,’ was running impeccably in the lead from the third hour and caused a sensation: they clinched the first diesel-powered victory in history at an average speed of 215.409 km/h. It was both fast and extremely clean. As a result, the TDI proved all the preconceived notions about diesels wrong once and for all. “It was impressive to see how clean this engine was,” says Ralf Jüttner. “When the car returned to the pits from the parc fermé and we were celebrating our victory, Ulrich Baretzky, Head of Race Engine Development, walked up to the winning car with paper napkins in his hands. He wiped the inside of the tailpipes and afterwards the napkins were as pristine-white as before. I’ll never forget this picture.”
And Audi was not done yet. They continued to dominate Le Mans in 2007 and 2008 with the R10.
