If you know anything at all about racing, then you know that Mazda is a huge player on the motorsports scene -- especially at the grass roots level. Mazda claims its brand has the most road-raced cars on any given weekend in the U.S. based on data the company has gathered. And the Japanese company has just broken new ground as the first automaker to use a compound turbocharged clean-diesel engine in motorsports under the hood of its Mazda6 GX car, which just scored the first-ever victory for a diesel-powered car in the Grand-Am series at Road Atlanta.
At Mazda's 7th annual motorsports media update lunch, I got an in-depth look at what Mazda has been up to recently in the world of motorsports. Here's a breakdown of the biggest topics discussed during Mazda's presentation.
Skyactiv-D Clean Diesel race car:
Trying to use as many stock Mazda parts as possible made the project both difficult and easy. This platform was setup for the Mazda6 GX Grand-Am car in order to see if a future LMP2 platform application would be possible. But difficulties in actually getting the program approved in several series proved difficult. Grand-Am had not allowed the use of turbocharged diesel engines, so Mazda had some convincing to do. Another first was a NASCAR-owned series that allowed diesel fuel. This was the first of several roadblocks for the project, not to mention that there's hardly any aftermarket for motorsport diesel engines.
The team at SpeedSource was responsible for developing the engine and the first thing they noticed when uncrating the stock engine was the casting quality was beyond what they had seen on other engines as well as the traditional Mazda length fasteners.
Development of the Skyactiv-D started at the core with the upper engine block, lower engine cradle, cylinder head and front timing cover. The cylinder head was used as is from the box while they added their own valve springs.
A lot of time was spent on the crankshaft, connecting rods, pistons and wrist pins. While most of the parts were Mazda-sourced, the crankshaft was replaced with a piece that could withstand higher stress race situations. The connecting rod's design was changed for optimal performance and serviceability. The thought behind this was that if they were more reliable and easy to service, then more customers would use them. Mazda pistons were used, which are optimal for diesel engines, but there was a buildup of stress in the wrist pin area that needed quite a bit of attention.
The dry sump oil pan had to be significantly restructured for race duty. The entire pan started at sixty-five pounds and in the end it weighed in at thirteen-pounds. While the valvetrain was fully Mazda parts, the intake manifold was not (for packaging reasons). SpeedSource ended up using a center feed manifold, which is very efficient. Although the valvetrain was a Mazda part, there were several pieces changed, including stiffer valve springs and the camshaft-timing wheel. The variable valve timing was removed and replaced with ridged lifters, which are more reliable for racing. The turbo in this tubocharged clean diesel engine comes from two turbos, one small and one large, which in turn causes the Mazda6 GX racecar to use two intercoolers.
The Grand-Am races leading up to Road Atlanta -- the Rolex 24 at Daytona and the Circuit of the Americas event -- provided valuable feedback for Mazda and SpeedSource. The Daytona race featured three Mazda6 GX racecars, which resulted in changes to the pistons because of intense pressure caused by thermal fatigue among other issues. COTA brought better results with the first finish for the Mazda6 GX, second place in the GX class as well as leading the most laps during the race. But with success came some issues such as broken drive shafts, which were designed for 700 hp regular gas engines but the power stroke is so strong in a diesel that it ended up failing the components. As a result the driveline was redesigned in roughly three weeks switching to steel components on the driveline.
Engine configuration is as follows for the Skyactiv-D motorsports:
Mazda's world of motorsports:
A lot of well-known figures in motorsports feel that Mazda is a good fit for carrying on the family legacy. Several well-known fathers sent their sons to participate in the world of motorsports under Mazda's wing: Andretti, Brabham, Cindric, Daly, Herta, Hobbs, Mansell, Newey, Rahal, Robinson and Varsha among them. If any of those names sounds familiar, they should, each and every one of those them has had an enormous influence in motorsports and are continuing the tradition with their sons.
The 2013 MazdaSpeed 7 were introduced at the event, which consisted of seven young men who have made a significant impact in motorsports driving a Mazda, including: Matthew Brabham (2012 USF2000 champ), Yago Cesario (2012 Skip Barber Karting Shootout champ), Patrick Gallagher (2012 Mazda Club Racer shootout champ), Jack Hawksworth (2012 Star Mazda champ), Bryan Hixon (2012 Skip Barber MazdaSpeed challenge), Stevan McAleer (2012 Playboy MX-5 Cup champ), Peter Portante (2012 Skip Barber Series Shootout champ).