We are challenging the final piece of conventional wisdom [about diesel engine cars]," said Audi AG Chairman Rupert Stadler. Certainly, he has the right car for the job. The R8 TDI concept's 6.0-liter V12 twin-turbo engine develops 500 horsepower and 737 lb-ft of torque. It nails the 0-62 mph sprint in 4.2 seconds, with a top speed of more than 186 mph. And that mountainous torque is available at just 1750 rpm.
Derived from the V12 unit powering the R10 racecar that has twice run the prestigious and demanding Le Mans 24-hour race, the engine is just 6.5 inches longer than the V8 in the regular R8. Its narrow 60-degree angle, and advanced materials combining iron and graphite make it compact and light enough to fit the R8 shell.
How clean is it? Clean enough to meet the ultra-tough California emissions standards that still defeat many lesser diesels. The secret to this is advanced combustion control, involving as many as five fuel injection events per engine cycle, combined with a three-stage exhaust treatment. A standard catalyst and particulate filter are fitted to remove pollutants and soot. An additional catalyst uses small quantities of an additive called AdBlue to break up nitric oxides. This system will last the lifetime of the vehicle.
Fuel economy may not be top of the criteria list for supercar buyers, but the R8 V12 TDI concept scores even here, testing at 24 mpg.
The transmission is a short-throw six-speed manual with a small diameter clutch for quick, precise changes. Naturally for Audi, and necessarily with so much power, there is a Quattro four-wheel-drive system.
The concept's exterior is a lightly restyled version of the familiar R8. Up front, additional layered air vents sit below the distinctive LED rimmed headlights. The aluminum bodywork is finished in matte silver, contrasting with the "side-blade" that vertically transects the body behind the cabin. The glazed cabin roof and engine cover are two transparent sections separated by a race-derived air duct that accelerates air into the engine. The rear of the car has a variable spoiler that extends upwards.
With the standard R8 already on sale and very well-regarded, it's entirely possible that this concept could be produced, albeit at low volume. But it's equally important to Audi as a way of making a point about the potential of diesel engines to deliver economy, cleanliness, and performance.
With a diesel in the R8, "the sky is the limit," said an Audi board member.
Almost overshadowed by the R8 concept was the world debut of the TTS. The introduction of this even sportier version of the renewed TT sports coupe and roadster marks the original TT's 10 year anniversary.
Its 2.0-liter turbo FSI engine is extensively revised from the standard unit. Delivering 272 horsepower, it can achieve 0-60 mph in 5.4 seconds with the manual transmission. Fitted with the S-tronic dual-clutch automatic, it is 0.2 seconds faster.
Fuel consumption is around 29 mpg in either case. Styling changes are subtle, but deeper skirts, new bi-xenon headlights and standard 18-inch wheels separate the "S" from other TTs.