If you were having a conversation with someone about racing and someone brought up diesel, what would be your first thought? For most, it would be Audi and their prototypes racing around the famed Le Mans circuit. But there is another player in the diesel racecar madness and that would be Mazda. Last year, the Japanese automaker raced three Mazda6 cars equipped with the Skyactiv-D engine in the Grand-Am endurance series. This year, Mazda took the same Skyactiv-D engine and put it into an LMP2 race car for the TUSC series. Autobytel's Michelle Naranjo talks with Director of Motorsports for Mazda, John Doonan, about the change and how far they have come.