Audi R8C

Audi R8C

Audi R8C at Le Mans Classic 2010
Category	LMGTP
Constructor	Bentley Motors Limited
Designer(s)	Peter Elleray
Technical specifications
Engine	Audi 4.0 litre 90-degree V8 twin-turbo,
Competition history
Notable entrants	Audi

The Audi R8C was a Le Mans Prototype automobile built by Audi for the 1999 24 Hours of Le Mans designed by Peter Elleray. It was developed alongside the open Audi R8R spyder, prior to being replaced by the all-new Audi R8 in 2000.

.Development

At the time of Audi's announcement of its intention to enter the 24 Hours of Le Mans in 1998, the plan was to enter an open-cockpit prototype, known as the Audi R8R. However, following the dominant performance of GT1-class cars in the 1998 24 Hours of Le Mans, the Automobile Club de l'Ouest (ACO) modified classification rules in order to create a new class known as LMGTP, which would be closed-cockpit prototypes, realistically replacing the powerful, purpose-built GT1 cars

Following this rule change, Audi decided that it should invest in this new LMGTP class, thus forcing it to design a whole new car, vastly different from the R8R. With the aid of Audi's new engineering partner Racing Technology Norfolk (RTN), Audi designer Tony Southgate set out to design the new R8C, unlike the R8R which was built by Dallara.

The R8C and R8R both used the 600 hp (450 kW) 3.6 litre twin-turbocharged V8 engine, but were radically different aerodynamically. While the R8R would have a large number of vents on the nose of the car, most of the intakes and air exits on the R8C would be placed on the side of the car. The R8C would also use thinner wheel arches, partially due to LMGTP rules stipulating that LMGTPs used thinner tires in comparison to LMPs in order to make up for the better aerodynamic efficiency, and thus increased potential speed, of closed-cockpit cars. Using a styling feature borrowed from the Toyota GT-One, the inside of the front wheel arches would also be opened, in order to not only allow air to exit from the front wheel wells, but also to assist in brake cooling.

For the cockpit of the R8C, a long sloped windshield would extend far down the nose. For the roof, the minimum roof height would be achieved with the use of raised humps above the driver's position, yet would be lowered in between these humps for better aerodynamic efficiency to the rear wing.

The rear of the car featured a boxy, blunt tail that was developed from the improved R8R, yet would be longer in order to better maximize the coupe's aerodynamics.

Racing history

Unlike the R8R, which performed the bulk of the testing because they were completed first, the R8C had very little time to test prior to the initial group test for the 24 Hours of Le Mans in May. At this group test, the cars suffered numerous setbacks and lacked the pace of the open-cockpit brothers. Although they were capable of hitting speeds upwards of 350 km/h (217 mph) on the Mulsanne straight, they lacked the handling ability and overall speed for a full lap. While the R8Rs managed the 8th and 11th fastest times, the R8Cs could only muster 22nd and 28th fastest. The R8Cs mostly suffered from aerodynamic problems, especially in the build-up of air underneath the engine cover. This caused the R8Cs to lose their rear engine covers on several occasions while at speed.

For the race itself, the R8Cs were unable to find much improvement over the month off. Qualifying was more of the same, as the R8Cs managed only 20th and 23rd places, while the R8Rs were still 9th and 11th. During the race, both the R8R and R8C suffered numerous gearbox difficulties. One R8C was forced to drop out of the race after just 55 laps, while the second R8C succumbed to gearbox failure after the midpoint of the race. Even though the R8Rs suffered gearbox difficulties, both cars managed to finish the race, taking third and fourth place.

Following Le Mans, Audi decided it would concentrate on only one of the two types of cars for the future of their program. The dismal performance of the R8C, along with the exodus from the LMGTP class by most major manufacturers, led Audi to develop an open-cockpit car - the R8.

Audi returned to the LMGTP class in 2001 in the form of the Bentley EXP Speed 8. Although similar to the R8C, the EXP Speed 8 shared nothing with the previous LMGTP except for its Audi turbocharged V8. Aerodynamic lessons from the R8C were, however, carried over for the Bentley.

Only two R8Cs were ever built, chassis #101 and #102, both raced by Richard Lloyd's Audi Sport UK. The 1999 24 Hours of Le Mans would be their only competition.

Audi returned to the closed-cockpit competition in 2011 when new regulations took effect: the new car is called the R18; Wolfgang Ullrich stated in an Autosport interview in 2010 that the R18 will be a closed roof coupe similar to the Peugeot 908 HDi FAP, the R8C and the Bentley Speed 8.