According to Uwe Haller, kooordination konzeptfahrzeuge for Audi AG (Ingolstadt, Germany), an engineer whose job it is to work on concept cars for the company, the development of the Audi R8 TDI Le Mans had three months cut out of its program. He explains that the car was originally slated to appear at the 2008 Geneva Motor Show in March, but was moved up to be revealed at the 2008 North American International Auto Show in January. And while this is a concept car, it, like all of the concepts that Haller and his colleagues put together, is a drivable vehicle. In this case, it is a drivable vehicle that produces 500 hp and 737.56 lb-ft of torque (and peak torque is reached at just 1,750 rpm). It can go from 0 to 62 mph in 4.2 seconds and has a top speed in excess of 186.41 mph.
One more thing about it: The powertrain for this mid-engine vehicle is a diesel. That’s right, a 6.0-liter V12. It is a variant of the V12 TDI engine used in the Audi R10 sports prototype cars that it runs at Le Mans.
In order to fit into the snug engine bay of the R8, the firewall was moved forward about six inches, Haller says. But it should be noted that the engine is, comparatively speaking, compact: the engine is 26.93-in. long, which is just 6.54 in. longer than the V8 TDI engine. The distance between cylinder bores is 3.54 in., and the included angle is 60°. A turbocharger is tasked to each bank of cylinders; the twin turbos generate up to 2.6-bar of boost pressure and contribute to the peak torque that’s sustained through 3,000 rpm. The specific output of the engine is 84.3 hp per liter of displacement.
And in case you’re wondering: the car fulfills the Euro 6 emissions standard that may be implemented?.?.?.?in 2014. Yes, it is a clean diesel.
The concept car is fitted with a six-speed manual transmission that was borrowed from the Audi A4. Presumably, if this vehicle were to go into production, there would be something else in its place.
Like the production R8, the engine, which is a work of art, is visible through a redesigned glazed engine compartment cover. Glass is also used for the roof. For the R8 TDI Le Mans, there is a NACA duct* formed in the roof: it is functional.
Inside, the cockpit, the vaunted Audi-quality interior is entirely up to snuff. While the production R8 has aluminum trim throughout, the R8 TDI Le Mans has even more aluminum, as well as the deployment of carbon fiber for trim.
The body is aluminum, based on the ASF—Audi Space Frame—principle. That is, the support structure is fabricated with extruded aluminum sections and die castings; the aluminum panels fitted to it perform load-bearing rolls. The entire body shell weighs 462.97 lb.
So what do you use to stop something like this? Ceramic brakes. The discs are a carbon fiber-reinforced ceramic. There are six piston monoblock aluminum calipers per wheel. Like the aluminum, the ceramic brakes are weight savers: it is an overall save of 44.09 lb.
The clock may have run a bit faster for Haller and his colleagues. But they certainly got the job done. Asked if he’d ever like to move from concept car development to a production program, he answers “No,” adding, “Too much paperwork.”—GSV
*NACA? That stands for National Advisory Committee for Aeronautics, the precursor to NASA. The duct provides air without disruption of the flow. While the R8 TDI Le Mans is meant to be a daily driver—for people who have rather substantial amounts of money to spend on their motor vehicles—the NACA duct is more commonly found on race cars.