The Audi R8 V12 TDI concept is the first 12-cylinder diesel engine to find its way into a high-performance roadgoing sports car. Until now diesel engines have offered a poor ratio when it comes to power output vs. weight, so while they’re ideal for a massive ocean-going freighter, they’re not so great for a high-performance supercar.

http://www.ohgizmo.com/2008/01/19/naias-2008-audi-r8-v12-tdi-concept-ill-ta...