Back in 2005, Audi had been dominating the endurance races with their R8. To stop this, the Automobile Club de l’Ouest decided to implement some performance restricting mods to the R8, such as bigger restrictor plates and a weight ballast. All of this heading to the 24 Heures Du Mans wouldn’t do much except for almost taking away any chance of having a competitive car in the most iconic race. Seeing that the car's competitive time had come to an end, Audi started development on a new car.
The new R10 would make its debut at the 12 Hours of Sebring, the American Le Mans Series’ main race of the calendar. Similar to the C4 WRC that would debut across the pond later, the R10 proved to be successful from the first race, taking the win to Intersport Racing’s Lola B05/40.
Departing from the R8's 3.6l twin-turbo V8, Audi decided to up the ante and take a special approach, last seen in the 1950´s, to Le Mans. Taking the diesel route, a twin-turbo V12 was fitted to the car. Yes, a V12 diesel engine that’d be raced at the most gruesome race ever. This uncommon engine produced 649bhp, and could make up to 799 more with an overboost button during a brief 10 second mark. The surprising number, though, was in torque, where it produced 948 lb-ft of torque. Engine displacement was the biggest allowed by the ACO, 5.5 liters of diesel pull, revving only to a redline of 6500rpm. Garrett supplied the turbos, limited to a 2.94 bar compression limit. Engine management was controlled by Bosch’s latest generation Motronic ECU. 2000 bars of pressure through Bosch common-rail injectors were more than enough to get fuel into the cylinders.
That unearthly amount of torque was toned down by a 5 speed manual gearbox developed by gearbox masters X-trac. This gearbox would finally send power to the rear wheels only, with an adjustable multi-plate LSD sending the massive amounts of torque to the wheels.
The chassis was built almost entirely by Audi, while Indy Car builder Dallara lent a hand (90% was built by Audi, the rest by Dallara). The structure was a carbon fibre monocoque that had to be enlarged in order for the massive new engine to fit between the wheels. The aero package was also modified to comply with the ACO’s new rules, and they also saw themselves forced to build a car with a minimum weight of 925kg, a 25kg increase over the last season’s minimum. This raise was added so that the closed-top LMP1s could add an air conditioning system (This weight was meant to equalize the field, so that the A/C’d LMP1s remained competitive after the weight increase the A/C system brought with it)
Double wishbones, anti-roll bars and a torsion bar with a separate damper were utilized all around the car for the suspension setup, and alloy slotted brakes helped to stop the 935kgs of mass. The car achieved mechanical grip thanks to 330mm section tires up front and 370mm section tires in the back. Those wide rubber rings were adornated by lightweight magnesium OZ 18-inch rims.
The R10 had proved it was a good contender since the first race, the 2006 Sebring 12 hours. Drivers Rinaldo Capello (ITA), Allan McNish (GBR) and Tom Kristensen (DEN) were given the task of driving the R10. For the first season, the R10 had reliability issues and couldn’t complete the whole season. The privateer R8s, on the other hand, were able to compete in the entire season. For that year’s Le Mans 24h, they were intending to leave one for the history books, in which they’d attempt to win, for the first time ever, in a diesel powered car. Their hopes already had a good start, with cars #1 and #2 getting 2nd and 1st place respectively (the classic switcheroo), leaving the Pescarolos behind by two seconds flat.
After achieving pole position, the hopes for Audi Sport Team Joest were pretty high up, after all, if they won, it’d be the first time a diesel powered car would take the victory at Le Mans, after Delettrez’s (1950s) and Lola/Caterpillar’s (2004, retired due to transmission failure) failed attempts at conquering La Sarthe.
Against all odds, the advantages a diesel car supposed ended up being the main factor that allowed the Team Joest to take the victory at the 24 Heures Du Mans of 2006. The R10 didn’t get a close win by any means; instead, they won by a good margin. A 4 lap margin over Pescarolo’s #17 racer, which was also driven by Loeb; they didn’t get the 1-2 sadly (As if winning the LM24H in a diesel wasn’t good enough), due to car #7 (pole-holder) finishing third, 14 laps behind due to several injector issues.
Nearing the end of the year, Audi snagged their seventh Petit Le Mans victory in a row. The team’s second car ended several laps behind as the consequence of a late race accident. The debut season was a very successful one for the Ingolstadt brand, with the V12 turbo diesel monster winning every single race it participated in, giving the team 8 wins in total, with ALMS and the 24HDM combined.
If the 2006 season was good, the 2007 one would be even better. Audi took the Sebring 12 by storm, again. They also won Petit Le Mans, apart from showing themselves victorious in every ALMS race they participated once more. That year’s Le Mans 24 were, let’s say, successful, but not that much.
In an attempt to defend this year’s race from Peugeot’s new , diesel-powered 908 HDI FAP, Audi entered a three car army. Sadly for them, Mike Rockenfeller (GER) made a mistake early in the race and saw the team having to race with only two cars against Peugeot’s three racers. In the first hours of the morning, Capello had a crash because of a poorly adjusted wheel, causing him to smash into a barrier at near 186mph (300kph). With only one car left, Audi still managed to defend themselves for the rival oil burners.
The 2006 and 2007 seasons were good and subsequently more challenging, and the 2008 season was bound to be more competitive and harsh for Audi. April 6th, 2008, Cataluña, Spain, the R10 loses its first race in the LMP1 category. This one was the inaugural race for the Le Mans Series, season that was completely dominated by Peugeot’s 908, except for the last event at Silverstone, in which McNish and Capello got the win. Peugeot’s dominance didn’t mean they would end up winning the championship. This honour would go to Audi, who although they won only one race managed to take the championship. Across the pond, in the U.S of A; Audi still dominated the whole season, except for Detroit’s race, an event in which one of their cars crashed and the other one was disqualified after not going through the required technical revisions.
Although not very successful in Europe, American soil races and Le Mans were Audi’s strongholds. If you had thought this year’s Le Mans was going to be less successful, you are wrong. Yes, they were more challenging, but that didn’t mean they were going to lose.
Since quali, this year’s race had already shaped up to be the most challenging for Audi to date. Peugeot had positioned their three 908s in the top three spots, leaving the Audis behind by more than 5 seconds. When the race started, the Peugeots begun pulling on the R10s, making a 5 second difference per lap, although Allan McNish was driving two seconds faster than the other Audis, three seconds are a big margin. Not everything was silk-smooth for Peugeot, finding themselves repairing the pole holder car. After 12 hours of racing, the #2 Audi was already on the second place, just behind Peugeot’s #7 car. There, it was when rain started pouring again, and Tom Kristensen begun completing laps 8 seconds quicker than Minnasian’s Peugeot, allowing him to cut the whole difference between the two cars.
Peugeot then decided to get the car into the pit to swap the bumper for the new conditions, a choice that allowed Audi to take the lead with a one lap advantage when the sun was coming out. Since quali, this year’s race had already shaped up to be the most challenging for Audi to date. Peugeot had positioned their three 908s in the top three spots, leaving the Audis behind by more than 5 seconds. When the race started, the Peugeots begun pulling on the R10s, making a 5 second difference per lap, although Allan McNish was driving two seconds faster than the other Audis, three seconds are a big margin.
After the track had dried, the Peugeots eventually started going faster round La Sarthe, but Minnassian made a bad choice. He decided to stay with the slick tires, and when nearing the race completion it begun raining again, he spun out of the track, gifting Audi their 5th win at Le Mans... in a row.
After four successful seasons, Audi retired the R10 in order for it to be replaced with the new R15 TDI. This didn’t mean the R10 would stop racing, because Audi sold many of them to privateers, including two units sold to team ByKolles. Raced until 2010, a 7th place at the 2009 24 Hours of Le Mans was the best place secured, 13 laps behind Peugeot's winning 908
Rounding up, the R10 TDI was the proof that different doesn’t mean worse. Out of the 48 races it participated in, it managed to win 36 of them (Counting Kolles’ and Audi’s efforts), and also made history in being the first diesel powered car to win at the gruesome 24 Hours of Le Mans. The R10 was a car that sparked an era of diesel powered LMP1 cars that didn’t stop until the retirement of the R18 E-Tron Quattro.
This article was part 1 of an ongoing retrospective series about the LMP1 class that will soon cease to exist after the 2019 24H of Le Mans. More articles will follow in the coming week, each from different creators.