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Mazda races diesel-powered sedans in Rolex 24, retires early

The Mazda6 Skyactiv-D makes a bold showing but quits after engine failures.

By Mike Meredith Jan 29, 2013 6:43AM

Following in Audi's footsteps of diesel-powered race cars, Mazda entered the first-ever diesel competitors in last weekend's grueling Rolex 24 at Daytona.

But despite years of successful racing experience and hundreds of hours testing the new engine on the dynamometer, Mazda soon learned that a 24-hour race is a tough way to debut a new race car. All three cars -- based on the upcoming 2014 Mazda6 Skyactiv-D diesel sedan -- suffered from engine failures during the first few hours. Two cars retired after losing a cylinder, and the third car suffered a rear main seal failure.

Still, John Doonan, Mazda's motorsports director in North America, said the automaker purposely chose to test the new engines at Daytona despite not having enough experience on the track.

"The Mazda and SpeedSource engineers have over 400 hours on the dyno but only a few on the track," Doonan said in a release. "Our on-track testing was limited in part due to the timing of our Mazda6 production-car launch, which prevented the team from getting on track as early as desired. The easy way out would have been a midseason debut, but Mazda has never taken the easy path."

Mazda teamed with SpeedSource Engineering to develop the new car, which is the first diesel-powered car to compete in the Grand Am series. The race engine, which makes 400 horsepower, includes more than 250 stock components, including the same engine block and heads as used in the production car.

The Rolex 24 was the debut race for the GX class, a brand-new Grand Am category that originally was restricted to alternative-fuel race cars. The rules have loosened since the category was announced in June to allow race cars that otherwise would not be allowed or competitive in the series, such as the winning (and gasoline-powered) Porsche Cayman.

Mazda has achieved a total of 23 class wins in the annual 24-hour race that marks the start of the racing season each January, with the RX-8 topping the GT class in 2008 and 2010.

Audi won the 24 Hours of Le Mans in 2011 with its R18 diesel prototype, and at the Rolex 24 clenched a 1-2 win in the GT class with a duo of R8 models. With Audi's success, it will be very interesting to watch the development of the production-based Mazda6 Skyactiv-D as a race car. With Mazda’s wins in the Grand Am with rotary engines -- a totally different and altogether complex engine in itself -- expect to see more from the Mazda6 Skyactiv-D once the team gets more development time on the track.
Jan 29, 2013 7:29AM

I believe Mazda offering a diesel in their new 6 (and hopefully later in the CX-5) is a significant positive for those of us diesel fans.


I was really hoping for some success in their racing debut so as help promote their technology.  Apparently, from reading another article on these "failures", they can be attributed to teething problems and some trivial mechanical part as opposed to a poor engine design.  Especially considering they're getting over twice as much horsepower out of it.


I wish them good luck in the future.  I can't wait to test drive this diesel engine!

Jan 29, 2013 12:45PM
Go Mazda!  Want to a diesel in the CX-5 and the 3!
Jan 31, 2013 8:58AM
From what I was reading, 2 of the vehicles suffered from loose nuts on the fuel lines which starved the cylinders.  This might be considered engine failure but its not like the engine blew up.  

I guess they had vibration problems, which is understandable since they are getting an incredible 400 HP out of a 2.2 Liter stock Diesel Engine block.  This 400 HP is more than twice the normal output for this engine.

It sounds like they rushed to get these cars racing with minimal track time.  With more testing and track time they may have been able to control some of the vibration and never have lost the fuel lines.

Jan 30, 2013 7:11AM
So when they are at the truck stop, will they just leave them running?
Feb 1, 2013 7:44AM
"i hope this stifles peoples belief that diesels last longer with the new fuel!?"

This has nothing whatsoever to do with fuel. I have been running my 2004 mazda6 diesel for years on 5 PPM Sulfur diesel, as does the rest of the European continent. That is three times less than United States federal norm. Never had a problem. The contemporary diesel engine is specifically designed to run on low Sulfur fuel.
Feb 4, 2013 10:43AM
"they were winning races now diesel power i hope this car doesnt work out so they bring back the rotary engine"

Forget it. Time of the gasoline engine is at an end. This is a new era, the era of ultramodern, environment friendly, quiet, powerful, fast diesels.

"the mazda 6 is an ugly looking car looks more like a hyundai"

Unfortunately, you are right. It is kind of ugly, and it most certainly looks like a Hyundai, which is not a compliment but an insult.
Feb 1, 2013 7:48AM
"Want to a diesel in the CX-5 and the 3!"

mazda3 already has a diesel engine, and has had one for years; mazda just refused to sell it on the North American market.

mazda3 - OK, CX-5 is an SUV. SUV's should all be withdrawn from the market and never spoken or written about again, except to illustrate how bad they were and the stupidity of the human race in general for mass-adopting them, without the practical need to do so.
Feb 1, 2013 7:41AM
mazda had a winning car in the rx8 ,they were winning races now diesel power i hope this car doesnt work out so they bring back the rotary engine ,the mazda 6 is an ugly looking car looks more like a hyundai
Jan 29, 2013 2:00PM

"All three cars -- based on the upcoming 2014 Mazda6 SKYACTIV-D diesel sedan -- suffered from engine failures during the first few hours."


i hope this stifles peoples belief that diesels last longer with the new fuel!?

not to mention a dying breed automobile manufacturer.

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