Audi has done many crazy things in the past, but putting a twin-turbocharged V12 diesel engine in the Audi R8 might take the cake.

Nine years on from their first appearance, Audi’s diesel Le Mans racers still divide opinion like little else in motorsport – short of F1’s decision to run turbocharged V6 engines.

The original R8R made its 24 Hours of Le Mans debut in 1999 powered by an all-new twin-turbo 3.6-litre V8; Audi’s first purpose-built racing engine since the 1930s. The centrepiece of the engine ...