Despite Porsche's and Toyota's success with their gasoline-powered prototype, Audi is sticking to diesel. The powertrain is a closely guarded secret right now but expect a modified hybrid system with lithium-ion batteries for energy storage, plus an efficiency-optimized TDI engine.

The new Audi entry may not win any awards for beauty in this form. But this is an upgraded aero package that feels very Porsche-like.

No word yet on driver lineup. But Audi has worked with Porsche to agree on only fielding two teams instead of three in order to keep costs down.