While it may not be touting the old "Win on Sunday, sell on Monday" axiom we all know and love, Mazdarecognizes that racing can only improve its cars. And so it's no surprise that the Japanese automaker is testing and refining its Skyactiv-D diesel engine by sending it out on various race tracks around the country – notably being the first diesel ever to compete at Daytona and the first to notch a Grand Am win at Road Atlanta.

Next up? Indy. It has been over 60 years since a diesel-powered machine ran at the Indianapolis Motor Speedway, and the Cummins-powered racer that competed in the 1952 Indy 500 with a 6.6-liter inline-six-cylinder oil-burner was a fast and brutal machine that set a new lap record in qualifying leading up to the race. Though that car was withdrawn with turbocharger failure 71 laps in, its diesel powerplant left an indelible impression on the racing community, and that's something Mazda hopes to accomplish once again.

Mazda says that the diesel engine in its race car is pretty darn close to stock – 51 percent stock by parts count, and 63 percent stock by weight – which means the way it performs in competition is at least a somewhat meaningful way to the stock engine's durability in the real world. Check out the image of the Mazda6 Skyactiv-D racer posing alongside the 1952 Cummins above (click to enlarge) and feel free to peruse the press release below for the rest of the details.