Audi starts the 2011 sports car season in the 12 Hours of Sebring on March 19. Making its final appearance is the Audi R15 TDI, which had to be modified to comply with the new regulations and which carries the project name “R15 plus plus” internally.
Timo Bernhard/Romain Dumas/Mike Rockenfeller (D/F/D), last year’s Le Mans winners, as well as Dindo Capello/Allan McNish/Tom Kristensen (I/GB/DK), Le-Mans winners from 2008, drive the two diesel race sports cars.
A long sports car season starts for Audi Sport Team Joest in March: On the agenda up to November are seven races, the Le Mans test weekend and numerous tests with the Audi R15 TDI and the new Audi R18, which does not, however, race at Sebring.
So as not to interrupt preparations for the 24 Hours of Le Mans on June 11/12 the test and development program with the R18 continues to run in parallel to the opening round of the Intercontinental Le Mans Cup 2011 (ILMC) season.
As a result one car in particular bids farewell at the 12 Hours of Sebring, a car that made its debut here two years ago: the Audi R15 TDI. It celebrated its 2009 premiere with a victory – the ninth for Audi in this traditional event in US state of Florida since 2000.
For the second appearance at Sebring the diesel racing sports car competes under completely new conditions.
New technical regulations from the Automobile Club de l’Ouest (ACO) are valid in 2011, for which Audi has developed the “closed cockpit” R18. Older models like the R15 TDI may only compete in heavily modified form with greatly restricted engine power. Just how these cars will fare against the new models remains to be seen.
The new LMP1 prototype regulations limit engine displacement for new models such as the Audi R18, which will contest its first race in May, to 3.7 liters. Older cars like the Audi R15 TDI will be slowed down accordingly.
To this end, the 5.5 liter V10 engine in the Audi R15 TDI must now draw air through two intake-air restrictors of 33.5 millimeter diameter – this is four millimeters less than before. At the same time the boost pressure is reduced by 23 percent to 2,000 millibar – 2,590 millibar was allowed before.
The fuel tank may only hold 65 instead of the previous 81 liters of diesel, the fuel flow restrictor in the autonomous refueling tank was also reduced by five to 28 millimeters. “The drivers felt the engine restrictions very clearly during the test in Florida.
They miss several dozen horsepower,” explains Ralf Jüttner, Technical Director of Audi Sport Team Joest. “The reduction in tank volume sounds drastic at first, but the engine obviously also consumes less. The slower flow rate from the external tank means that pit stops will certainly not be any shorter despite the smaller fuel tank volume.”
The Audi R15 TDI makes its farewell appearance in Florida in the hands of two successful driver line ups.
Timo Bernhard and Romain Dumas, who won at Sebring in 2008, share the car with start number “1” with Mike Rockenfeller. Dindo Capello/Tom Kristensen/Allan McNish, the Sebring winners in 2009, drive the “2” numbered Audi.
Two new partners are also part of the team for the first time at Sebring: Lining up alongside Bosch, Mahle, Michelin and TAG Heuer to partner the Audi sports car program from 2011 are Alpinestars, specialists for motorsport and extreme sports clothing as well as street wear, and lubricant manufacturer Castrol.
With Castrol a familiar face returns to the side of Audi Sport; the two companies were already very successful together in competition as partners in the DTM, super touring cars and in rallying.
Source: Audi
