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As is common practive with modern high power density diesels, the SKYACTIV-D uses a compound turbocharger system with two intercoolers. The autoshow display model shows an air-to-water intercooler between the two stages, but the race car actually uses air-to-air intercoolers in a V-mount setup for both stages of intercooling to cool the air down from the Garrett by Honeywell based turbos. So why use a compound turbo system? Using two turbochargers in this arrangement allows for a broad powerband and big power numbers. The small HP (high pressure) stage turbo comes on first and quick. The large LP (low pressure) stage gains speed as the engine speed climbs and provides the big power boost.
Extensive testing was performed on the engine dyno with the calibration and performance testing taking over 2000 dyno pulls. I saw the dyno chart for the engine and the compound turbo setup showed its worth; the engine is making over 90% of peak torque over about 75% of the useable engine speed range. The torque curve would make any engine guy envious. In the end, the race engine makes more than double the stock power and retains 51% of the OEM Mazda parts while doing so.
After the calibration work was completed, endurance testing commenced with both 50 hour and 30 hour endurance runs being performed. On top of that, a full simulated run of the Rolex 24 Hours of Daytona was run on the engine dyno using data from the 2012 race. As everyone in Motorsports knows, the final say is in the car on the racetrack and this is where the issues cropped up with the pistons and fuel lines at Daytona and Circuit of the Americas. However, the good teams learn from their mistakes and make corrections. SpeedSource did a good job as they took their first win at Road Atlanta!
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| The Mazdaspeed Seven (well, 6 of them, the 7th was doing testing at a track). |
Mazda Motorsports prides itself on providing a path for people to reach the top level of Motorsports. The Mazdaspeed Seven are drivers who have earned full-time rides in the various racing series that Mazda participates in. For 2013, Mazda is participating in: SCCA and NASA Club Racing, Skip Barber MX-5 and Formula Cars, SCCA Pro Racing Playboy Mazda MX-5 Cup, USF2000 Championship, Pro Mazda Championship, Firestone Indy Lights, IMSA Cooper Tires Prototypes Lites, Grand-Am Continental Tire Sports Car and Rolex Sports Car Series, and American LeMans Series. Some pretty famous alums with the names Rahal, Andretti, and Daly came up through the Mazda ranks.
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Mazda Motorsports this year is using some of their clout to help promote a cause. For this year, they are spreading the word on Project Yellow Light. Project Yellow Light is a scholarship competition started in honor of Hunter Garner who was just 16 when he was killed in a car accident. The goal of Project Yellow Light is to encourage teens to use safer driving habits and not drive distracted. In the years 2010 and 2011, over 3000 people were killed each of those years due to distracted driving with an additional 400,000 each year being injured. So the message is to keep your eyes on the road and hands on the wheel.
I've been fortunate to attend the Mazda Motorsports Media Day the last two years. There are always some cars to drool over, race drivers to bump elbows with, and I never turn down free food! This year, we had the added bonus of meeting the brains behind SpeedSource and seeing a sliver of the development process for a brand new race car. Keep an eye out for the SKYACTIV-D as the season progresses; it has already tested successfully very early in its development. It'll be great to see what it can do with even more development time.
