It is possible to look at Audi’s new-generation aluminum/carbon fiber-constructed V10 R8 supercar in two ways: its entire technology comprises 50% of the latest R8 LMS (Le Mans Series) GT3 racecar; alternatively, the racecar comprises 50% of the road car.
Driving the 449-kW (602-hp) version of the road car (previously described by Automotive Engineering at http://articles.sae.org/13959/) for the first time in gathering darkness on demanding mountain roads in the South of France made the point to this Editor. Jab the start button on its “multi-multi”-function Performance Steering Wheel and its V10 starts with a bark; shift into the Sport setting of its 7-speed twin-clutch transmission; choose the correct ambient conditions’ setting for the quattro system, spanning “dry to snow”; select Performance Mode via another button and push yet another to control exhaust sound- altering flaps; switch on its LED laser supported headlight system—and squeeze the gas pedal.
Zero to 100 km/h (62 mph) is reached in 3.2 sec, and 330 km/h (205 mph) could also be reached if a smooth, empty stretch of Cote d’Azur beach could be found, the quattro system, mechanical differential lock, and traction control ensuring that at no time would the R8 get stuck in the sand.
If more convincing evidence needs to be accrued to prove the 50/50 claim, Audi produced it. “What I found when I first drove the road-going R8 was how much it felt like the racecar,” said Oliver Jarvis, Audi’s motorsport team driver with successes that include the Sebring 12 hours, Daytona 24 hours, and two podium finishes at the Le Mans 24 hours. “With its stripped-out cabin, the racecar weighs so much less than the road car [Type Approval weight about 1225 kg versus EU dry weight excluding driver of 1454 kg], and it is certainly not as comfortable [no air con!] but the road car’s ‘directness,’ its power [race and road R8s have virtually identical engines], and the speed of the gearshifts, with the exhaust popping as you downshift, makes you smile.”
The aural signature of a true sports car even impresses race drivers.
Simultaneous development of road and race versions
The road and track link isn’t surprising because the second-generation R8 road and race versions have been developed simultaneously. Close cooperation between engineers, motorsport specialists, and developers has resulted in a road car that truly has benefitted from race technology.
Both share Audi’s Space Frame (ASF) architecture and that raucous 5.2-L V10 naturally aspirated high-revving engine. There is a choice of power outputs: 397 kW (532 hp) for the R8 V10, and 449 kW for the R8 V10 plus. The more powerful engine has both direct and indirect injection and each version has Cylinder On Demand, deactivating one of the car’s two banks of cylinders during partial load conditions. Depending on applicable regulations and the restrictor required, the LMS car typically produces 430 kW (576 hp).
Racing technology really does cascade down from Audi’s racing programs to the road-going R8, stated Jarvis, and it has done for years: “Such as advanced diesel and FSI (gasoline) engines, traction control, laser headlights—and once a technology performs successfully for 24 hours at Le Mans, you know it’s ready for the road! For Audi, racing is not just a marketing tool but a way of continuing to push the technology development process.
“For example, in a 24-hour race a significant way to gain an advantage is to have better visibility than other competitors, so headlights play a huge role in that.” The new road-going R8s have benefited from that race experience.
Audi states that the LED headlights with optional laser spots double the range of the high-beam light at speeds in excess of 60 km/h (37 mph). Each headlight incorporates a module with four laser diodes, each of 300-µm diameter, providing a blue laser beam having 450-nm wavelength. A phosphorus converter changes this to white light, having a color temperature of 5500 K. A camera-based sensor system detects other road users and actively adjusts the LED system to avoid glare.
Although it has similar looks to the first generation R8, the new generation has been very extensively re-engineered and is described by the company as the fastest and most powerful road-going Audi ever. The chassis offers greater comfort than that of the previous model. Aluminum double wishbones are used front and rear.
Dynamic steering (electromechanical) is available as an option for both engine versions, varying the ratio between 10.0:1 and 17.5:1.
Another option is magnetic technology. It is incorporated in the Drive Select dynamic driving system, which is standard equipment and can be used to vary the mode of operation of key technical components over four specific settings: comfort, auto, dynamic, and individual. In dynamic on a track, the quattro drive system assists in executing controlled, safe drifts, states the company. In the auto mode, traction has priority.
“Information sharing massively benefits the road cars; that’s why motorsport is so important for Audi. Reliability, efficiency, and performance are the three core areas that make Audis what they are,” said Jarvis.
Similar cars, yet different
But there are several big differences between road and race R8s. “Racecars are that much more aggressive in braking,” said Jarvis. “Racing for 24 hours they reach extreme temperatures, around 600-700°C. You drive a racecar absolutely on the limit all the time but it weighs much less than the road car so the brakes (carbon-carbon) have different requirements. For the road car you want to go out on a very cold morning and find the brakes work fully first time!”
And the steering: “On a racecar you get the feedback you need. But what has surprised me is how direct the road car feels—very much like a racecar,” he said. Transmission shift speeds also felt like a track R8, he noted: “No gap between gears and so smooth.”
The road R8 has benefitted not just from racing experience but also from track testing. “Tests are structured, perhaps endurance tests at the Paul Ricard circuit for 24-hour reliability of components. But there are also shorter runs for comparative work on components, such as tires for compounds or structure,” Jarvis said.
Weight balance is also crucial for drivability: “Many people don’t really understand the effect; the smallest shift in weight balance can have a huge effect on the handling of a racecar. It’s a tool we use a lot,” he shared.
It may make a track car harder to drive—but with faster reaction to driver input in the way that a modern fighter aircraft can be designed as an unstable platform for quickest responses, albeit with huge computer back-up. Varying weight balance on a road car is not practical, but it is the experience gained on the track that helps create an optimum for the widely varying conditions in which it is driven.
Jarvis is not an engineer (he has a Business Studies degree) but he has gained the technical knowledge essential for a race driver: “Working in the team and with the engineers you learn; you have to have an understanding of how systems work and why. Racecars like our hybrids are so complex you need to talk the language of the technicians. You can’t be just a race driver today.”
But now you can drive an Audi that is 50% a racecar, so arguably you could claim to be 50% racecar driver.Continue reading »