[22] The R10 carried over the R8's carbon fibre monocoque and aluminium honeycomb, with the plastic bodywork replaced by a carbon-fibre composite construction, necessitated by the increased weight of the V12 compared to the previous V8.

[22] Audi was not the first to campaign a diesel-powered car at the 24 Hours of Le Mans, with French brothers Jean and Jacques Delettrez being the first to field a diesel.

[23] After retiring with valve failure in 1951, the Delettrez brothers were the last diesel-powered entrant until privateers Taurus Sports Racing entered the 2004 24 Hours of Le Mans with a Lola B2K/10 that was powered by a 4,921 cc (300.3 cu in) V10 TDI from a Volkswagen Touareg.

[23] In the early 2000s head of Engine Technology at Audi Sport Ulrich Baretsky met with Automobile Club de l'Ouest officials to discuss the direction endurance racing went in the future.

"[20] Then-chairman of the board of Audi AG Martin Winterkorn reiterated this during the car's presentation in Paris in 2005, saying "The Le Mans project will help our technicians to extract even more from TDI technology".

[28] During the 2004 24 Hours of Le Mans, Baretsky met with the then-chairman of the supervisory board of Volkswagen, Ferdinand Piëch, who gave the project the go-ahead.

[6][30] Allan McNish said the exhaust was so quiet that above 161 km/h (100 mph), the sound of wind rushing by was louder than the engine itself, making downshifting hard to do by ear.

8's exhaust pipes whilst the car was in parc fermé, and Ralf Jüttner, team director of Joest Racing, remarked that afterwards "the napkins were as pristine-white as before".

A favourable torque curve meant that a 6-speed like the one found in the R8 was unnecessary, and Xtrac provided a 5-speed pneumatically-actuated sequential with a ZF Sachs ceramic clutch, and Megaline supplied the gearbox control software.

[35] Champion Racing continued to field the car in the American Le Mans Series, although the R10 was replaced by the R8 following Sebring and was not reintroduced until the fifth round of the season at the 2006 Utah Grand Prix.

2 R10 broke the track lap record in qualifying en route to pole position at Sebring in an Audi front row lockout, but was forced to start from the pit lane because of an intercooler failure.

[53] At the inaugural 2006 Utah Grand Prix, Capello and McNish went into the race holding a comfortable lead in the championship standings as the R8 remained competitive, having been run for the previous three rounds.

20 Lola B06/10 started to close in on Biela, but rear suspension failure sent him into a heavy shunt just before turn five, and a full-course yellow was shown as the debris was cleaned up.

1 pitted on the third lap after an onboard camera became loose and fell into the footwell of the car, and McNish was issued with a stop-and-go penalty after causing contact going into Laguna Seca's famous "Corkscrew", forcing the team to replace his front fascia.

8 Peugeot 908 HDi FAP of Sébastien Bourdais, Pedro Lamy, and Stephane Sarrazin topped the timing tables during testing, posting a 3:26.707,[85] over a second and a half faster than the second-placed No.

[86] The weather forecast proved to be accurate, with all of qualifying the next day taking place in wet conditions; Bourdais duly set the fastest time, a 4:01.928.

[89] Bourdais led the off field in his 908 HDi but ran wide on the first lap at the Dunlop chicane and handed over the lead to Capello,[90] and soon the Audis were running in the top three positions.

2 R10 by three laps as the race passed the sixteenth hour mark, with Werner having lost time due to an unscheduled pit stop for a nose change after his contact with Magnussen.

[98] Biela, who still led the race at the time, ran wide at the first chicane on the Mulsanne Straight, before pitting for wet weather tyres, replacing the rear bodywork and handing over the wheel to Werner.

7 908 HDi rejoined in fourth place, but after a single lap around the circuit he came back into the garage to finally retire with electrical problems[101] just over an hour from the finish.

[102] Biela went on to take the chequered flag, and give Audi their fourth consecutive win at Le Mans, covering 5,029 km (3,125 mi) at an average speed of 209.15 km/h (129.96 mph), despite more than two hours and a half under the safety car.

"[104] Wolfgang Ullrich, head of Audi Motorsport, agreed, saying "This victory is the most difficult we have had at Le Mans", and that the team was "put under pressure by Peugeot right to the end of the race.

1 during Thursday night practice meant that his car suffered heavy damage, returning to the pits missing almost its entire left side.

As a result of the pit stop that lasted almost fifteen minutes, Kristensen dropped down to seventh, and had to come in again just a half-hour later for another battery, starter motor, and dashboard.

26 Acura of Bryan Herta, Dario Franchitti, and Tony Kanaan frequently exchanged the lead with the R10 throughout the race,[116] highlighting the competitiveness of the LMP2 cars following their 150 kg (331 lb) reduction in weight.

[117] At the first street circuit of the season, the inaugural Grand Prix of St. Petersburg, the R10s faced stiff competition from the lighter, nimbler LMP2 cars, which had the edge over the R10 in the corners but fell behind on the straights.

A yellow flag towards the closing hour of the race was brought out for Tomas Enge, who whilst leading the LMGT2 category in his Ferrari F430 GTC shunted heavily at turn 3.

[121] The next destination of the season, the 2007 Toyota Grand Prix of Long Beach was also a street circuit, nicknamed the "Monaco of the United States" due to its proximity to the coastline.

[136] Ultimately, changes that the Automobile Club de l'Ouest (the organisation responsible for the 24 Hours of Le Mans) made to the regulations meant that Audi's successful open-cockpit lineage came to a close prior to the start of the 2011 season.

Ullrich, despite his professed love for open-cockpit prototypes, explained how "the driver change [easier in an open car] is no longer the dominant factor in the time of the pit stop", and "It is getting more and more important to have maximum aerodynamic efficiency".