At the 2005 Le Mans the Audi teams were quick to admit that given the heavy performance restrictions (namely weight, aerodynamics, and power), they were not the fastest cars out on the track. The 2nd place French Pescarolo team turned in lap times about 3 seconds faster than the Audi cars. Where Pescarolo was faster, though, the #2 Lehto/Werner/Kristensen Champion Audi covered this ground with better reliability, fuel consumption, pit strategy and, of course, driving. The serviceability of the R8 is simply second to none. The modular construction allows the team to quickly change core components with minimal disassembly/reassembly. For example, the entire rear transaxle, suspension, and braking system can be swapped out as one assembly in a mere three minutes flat.
In 2004 a Le Mans rule was implemented stating that the entire gearbox could no longer be switched out during the race. Audi adapted to this rule change and redesigned the transaxle assembly to allow quick access to the gearbox internals, whereas previously they would have just replaced the entire box as a single unit. Being able to quickly adapt to rule changes is a necessity.
While racecar design is fundamental, a competent pit crew is also absolutely paramount in endurance racing. The level of poise, expertise, and efficiency we witnessed in the Champion Racing and Oreca pits during this year's Le Mans was nothing short of awe inspiring. Everyone knew their role. Tasks were accomplished expediently without interfering with another mechanic's work.
At about 12:52 am on Sunday morning, the number 4 Oreca R8 came into the pits with a problem in the right front upright/suspension system. It was quickly determined that the front end would have to be disassembled for diagnosis. In what can only be described as a flurry of blue, the car was wheeled into the paddock and no less than six mechanics were frantically ripping the front end off the car. To see these mechanics work together at an intense pace while not interfering with each other is a sight to behold.
The front suspension was dropped within three minutes, the parts replaced, and the car back out on the track moments later. Luckily for the Champion team, they experienced very few problems. Other than the minor damage incurred when the #3 R8 driven by Pirro went straight off the Terte Rouge, the pitstops in the Champion paddock were routine.
Victory at this year's Le Mans was against all odds. With the ongoing domination of the R8 platform, rule changes had been made year after year to keep the speeds safe and the playing field level. Once having more than 600 hp, today's R8 has been choked down with a 29.9 mm inlet restrictor mounted on each Garrett turbocharger compressor. This brings the 2005 spec Le Mans car down to about 520 horsepower and 700 Newton-meters (516 ft/lbs) of torque. Just for comparison, the Audi B5 S4 biturbo sedan utilizes an opening on each turbocharger of approximately 32 mm and is only rated at 250 hp.
Extra weight penalties on the R8 bring the minimum vehicle weight to 950 kg (2090 lbs) and the fuel capacity is smaller than before at 80 liters (21.1 gallons). Small aerodynamic differences including a compulsory underbody spacer reduce the downforce available. According to JJ Lehto of the #3 Champion car, "In this configuration with reduced power and more weight the Audi R8 is not enjoyable to drive. The car was always good and strong but I was never 100% happy and it was so easy to lose five seconds with traffic. It was impossible to get that time back - it was a struggle." Another Champion team member (making reference to the less restrictive nature of the American ALMS series, similarly stated that "at least in America, we can still drive a proper race car."
Despite the age of the platform, despite the extra performance restrictions, despite the lack of factory backing, the privateer teams of Champion and Oreca were able to take 1st, 3rd, and 4th places at the 2005 24 Hours of Le Mans - no small achievement. This performance clearly demonstrates Audi's commitment to high performance engineering; "Vorsprung durch Technik" has never been more true.
As a follow up to the massive success of the R8 the logical question is where Audi will take its motorsports efforts in the future. Unfortunately nobody yet knows for certain. Common speculation has Audi returning to Le Mans next year, but in what form remains to be seen.
A French motorsports source has published rumors that Audi is considering diesel power for its next Le Mans entry. Engineers are also looking to simplify the next car. For example, 4-way adjustable dampers were deemed unnecessary and over-complicated to the car's setup. A better designed system with fewer adjustments would naturally be sought. The biggest question of all is whether Audi can produce a successor to an R8 car which will undoubtedly leave an exclamation point in motorsports history.
Champion Racing 2005 Audi R8 Le Mans Spec:
Vehicle Type: Le Mans Prototype (LMP) 900
Monocoque: Carbon Fiber/Honeycomb FIA-ACO approved
Body Panels: Carbon Fiber/Kevlar Composite
Engine: 90-degree 32 Valve DOHC V-8 with Audi FSI direct injection. Twin Garrett ball bearing turbochargers with (2)x29.9 mm inlet restrictors. Twin side mounted intercoolers. Boost electronically limited to 1670 millibar.
Displacement: 3600 cc
Power: ~520 BHP
Torque: 700 Newton-meters (516 ft-lbs)
Drivetrain: Mid-engine, RWD
Clutch: Sachs multiple plate carbon fiber. 900 Newton-meter (664 ft-lbs) torque capacity, 7000km expected lifecycle.
Engine Management: Bosch MS 2.8 with full telemetry ability and electronic wastegate control
Engine Lubrication: Two-stage dry sump. Shell Racing SR oil used.
Gearbox: Ricardo pneumatically shifted six speed sequential unit with multiple plate limited slip viscous differential. Pressure fed lubrication system.
Driveshafts: Constant Velocity tripod joint
Front Axle: Double wishbone-rocker suspension. 4-way adjustable ohlins shock absorbers. Servo assisted rack and pinion steering. Ride height control.
Rear Axle: Double wishbone-rocker suspension. 4-way adjustable ohlins shock absorbers.
Brakes: Hydraulic dual circuit brake system with Brembo monobloc calipers. Full floating carbon fiber brake rotors with carbon fiber brake pads. Computer controlled driver adjustable biasing system.
Wheels: O.Z. forged magnesium rims with integral tire pressure monitoring system. Front: 13.5" x 18" Rear: 14.5" x 18"
Tires: Michelin Racing Slicks Front: 33/65-18 Rear: 37/71-18
Length: 4650 mm/15'3"
Width: 2000 mm/6'5.7"
Height: 1080 mm/3'5.5"
Minimum Weight: 950 kg/2090 lbs
Fuel Capacity: 80 liters/21.1 gallons