Audi R8 V12 TDI Concept Preview
By Jeff Youngs, February 24, 2012
- Chassis shared with the production R8
- 6.0-liter, V-12, twin-turbo diesel powerplant based on the V-12 model found in the Audi R10 race car
- 500 hp and 737 lb.-ft. of torque
- 0 to 62 mph in 4.2 seconds
- Top speed in excess of 186 mph
- Not announced for production
The R8 is Audi's premier 2-seat coupe sports car, launched in 2007. The R8 shares its name with the successful Audi race car, and its platform with the Lamborghini Gallardo. Touting an Audi Space Frame (ASF) aluminum body and a mid-mounted 420-hp V-8 engine with quattro permanent all-wheel drive (AWD), the production R8 demonstrates Audi innovation and experience learned from years of involvement in motorsports.
The Audi R8 V12 TDI concept is the first application of a diesel engine in a high-performance sports car designed for public roads: Audi has been winning races with their diesel-powered R10 race car for years. Audi hopes the 500-hp V-12 engine, mounted in the middle of the chassis, will help the vehicle to write a new chapter in diesel technology.
The Audi R8 V12 TDI concept is a show car that has not been announced for production. Regardless, it is striking in appearance with its matte "Grace Silver" bodywork and muscular proportions. Sharing the same basic architecture with the production Audi R8, the V12 TDI concept turns it up a few notches with additional details that allude to its racing heritage.The exterior of the concept features a unique aluminum front splitter. Swept around the front, the spoiler lip continues down the side of the vehicle to connect to the rear diffusers. The middle of the roof houses an unmistakable NACA duct: an aerodynamic design normally reserved for racing vehicles. On the R8 V12 TDI concept it is completely functional as it feeds air into the V-12 TDI engine in plain view beneath the restyled rear glass lid. The powerplant in the concept can be seen even after dark with the help of white light-emitting diodes illuminating the engine compartment-a feature shared with the production R8 version.
The interior of the R8 V12 TDI concept sports a 3-spoke steering wheel, covered in Valcona leather, with a lower flat edge and a lightweight magnesium core: another direct tribute to racing. Wheel-mounted buttons start/stop the engine and control suspension/throttle settings. In "Race" mode, the instrument lighting changes from white to red, and the navigation display shows a lap timer and track information. The driver can even call up information about centrifugal force or engine boost pressure. Compared with the production version of the R8, the V12 TDI concept features significantly more aluminum and carbon fiber throughout the cabin.
Based on the 5.5-liter diesel engine found in Audi's winning R10 Le Mans racing car, the V-12 engine in the R8 concept displaces a slightly larger 6.0 liters. The crankcase is manufactured from gray cast iron with vermicular graphite-a material known as GJV-450. This material is 40 percent more rigid and 100 percent more fatigue-resistant than gray cast iron.
Fuel is injected by two new dual-piston high-pressure pumps on a common rail direct injection system. According to Audi, the pumps build pressure up to 2000 bar (nearly 30,000 psi) within the rails before sending the fuel to special piezo injectors. The injectors are designed to allow main, pilot, and post injections of fuel-to reduce acoustic harshness, or increase the temperature of the exhaust gas for emissions reasons.
Twin turbochargers are located on the outside of the engine's cylinder banks, and each of them is tasked to supply up to 2.6 bar of boost pressure to six cylinders. Two large intercoolers reduced the temperature of the compressed air for increased power.
The engine is rated at an even 500 hp, producing 737 lb.-ft. of torque. (For comparison, a 10-cylinder 2008 Dodge Viper has 560 lb.-ft. of torque.) All of the power is sent through a traditional 6-speed manual transmission with a small-diameter double-plate clutch. An open gear lever gate guides the polished aluminum shift knob through the short throws. Audi's permanent AWD quattro system is standard on the R8 V12 TDI concept. In the case of this mid-engine sports car, power is normally distributed 40:60 with the high-tech quattro system able to automatically vary the torque split accordingly if needed. According to the maker, under full throttle, the Audi R8 V12 TDI concept sprints to 62 mph in 4.2 seconds. Audi officially lists the top speed as ".well over 186 mph."
The body is built with Audi Space Frame technology. Supporting structures are constructed with extruded aluminum sections and die-castings. Aluminum panels are then joined to this skeleton to perform a load-bearing role. The resulting chassis is lightweight, and extremely rigid. The suspension utilizes Audi's magnetic ride technology with shock dampers that are filled with a magnetically sensitive fluid that allows suspension changes within milliseconds. The system adapts to the road, and the driver's style, automatically. The braking package on the Audi R8 V12 TDI concept utilizes sizable 4-wheel ceramic disc brakes. With a total of 24 pistons, the lightweight and fade-resistant brakes are easily identified by their painted red calipers.
Audi utilizes clean diesel technology on the R8 V12 TDI concept. In its current state, the vehicle runs clean enough to fulfill Euro 6 emissions standards that are likely to take effect in 2014. Audi accomplishes this by sending the exhaust from the engine through an oxidizing catalyst and a particulate filter. From there, the spent gasses are injected with a special solution called "AdBlue." This clear, non-toxic, and safe to handle liquid is an aqueous urea solution that is broken down by hot exhaust gasses into ammonia. The ammonia splits the nitric oxides into harmless nitrogen and water. According to Audi, the AdBlue system in the Audi R8 V12 TDI concept is designed to remain effective for the entire service life of the vehicle.