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The Mazda Prototype is taking on the formidable task of challenging for the overall victory in IMSA Tudor Championship sports car races using the company's Skyactiv-D diesel engine.

Sports cars embrace array of green technology

The International Motor Sports Association’s Tudor United SportsCar Championship is the newly merged racing series for sports car racing in North America, ending the split between the American Le Mans Series and the Grand-Am racing series.

One way the new series aims to boost interest in its racing and its cars is by strengthening the link between the cars on the track and those on the street. This gives manufacturers and fans alike more reason to be interested in the racing series.

Manufacturers Ford, General Motors, Honda, and Mazda have all introduced production-based engines for IMSA racing that the companies hope will attract fan interest while they spur development of know-how for the engine’s production analogs.

The series has gone all-in for green technology, from the renewable component of its fuels, to the orange oil in some of its tires, to the efficiency of its racecars, said IMSA President Scott Atherton.

Bio fueling up

The cellulosic E85 fuel used by the Corvette racing team comes from Ineos Bio, whose Vero Beach, FL, processing plant converts bio waste from Florida’s “salad bowl” to create high-performance fuel that is separate from the food chain.

The company’s plant consumes vegetable and yard waste, and waste wood from citrus, oak, pine, and discarded pallets to produce 8 million gal (30 million L) of cellulosic ethanol per year, along with 6 MW of electrical power.  

“It helps solve waste disposal issues, contributes to the supply of affordable and renewable fuel and energy, creates attractive jobs, and provides a sustainable source of value for the community,” said Peter Williams, CEO of Ineos Bio.

Chevrolet burns Ineos Bios’ E85 in its Corvette racers to demonstrate the viability of the alternative fuel to customers, said Mark Kent, Director of Racing for Chevrolet. “We’ve raced with E85 in the Corvette for many years,” Kent noted. “The reason we did was that it not only allowed us to learn things in a rapid timeframe, it was also a great platform to demonstrate to consumers the viability of E85.”

Differences in the lubricity of E85 compared to gasoline drove changes to fuel system parts and valve seat materials in both the racecars and E85-certified production cars, Kent said.

Dynamic Fuels, meanwhile, supplies renewable diesel fuel produced from waste animal fat for Mazda’s diesel-powered prototype racer. Dynamic is a partnership between Tyson Foods and Syntroleum, and its refining process converts triglycerides from animal fat and grease to isoparaffins, creating a superior diesel fuel for racing.

Dynamic’s diesel boasts a cetane rating of more than 75, compared to pump diesel which can be as low as 40 in the U.S. It also has fewer than 1 parts per million (ppm) sulfur content, compared to pump diesel’s maximum of 15 ppm.

That cetane rating has let the Mazda Motorsports team turn up the boost in its Skyactiv Technology diesel prototype, reported Director of Motorsports John Doonan. “For us, because we’re having to squeeze more power and boost out of our little engine, it has allowed us a freer range of adjustment,” he said. “The [fuel] quality is at such a high level, any time we ask it for more, it is there for us.”

Where the orange meets the road

Fuel isn’t the only area where waste from the food industry can be repurposed for racing. Yokohama Advan ENV-R2 tires used in IMSA’s Porsche GT3 Cup Challenge USA are infused with orange oil recovered from waste from processing Florida oranges.

“It used to be a problem for [orange growers],” said IMSA’s Atherton. “There were mountains of pulp and peel that otherwise would have to be disposed of.”

Adding orange oil to the petroleum makes the tires’ rubber softer, providing more grip, according to Yokohama Senior Manager, Technical Engineering, Pat Keating.

“The purpose of orange oil is as a grip enhancer,” he said. “On a very fine level, we have more rubber flexibility. When you have a more flexible rubber in contact with the road you are more able to conform to those very small surface imperfections.”

The appeal of extra grip in a racing tire is obvious, but orange oil is also useful for boosting the fuel efficiency of tires for street cars, he added. That’s because the measures tire engineers would normally take to reduce rolling resistance also wreck tire grip, Keating explained.

“You don’t have to leave some of those things you want to do [to reduce rolling resistance] on the drawing board because you can put them in your tire and get your grip back with orange oil,” he said.

The company puts orange oil into its Avid Ascend touring tire and the Advan Sport V105 performance tire. “[Orange oil] blows up some of the normal engineering trade-offs we have to make,” he said.

Race what you sell

Naturally, carmakers are more focused on the cars and their engines than things like fuel and tires—which is why Ford, Chevrolet, and Mazda are making a splash by racing modified versions of their efficient production engines.

Mazda Motorsports wants to highlight the Skyactiv-Diesel engine that the company plans for sale in the Mazda6 family sedan, and after racing the engine in a production category in 2013, the company has switched to the Lemans Prototype 2 class for 2014.

In the production-bodied racer, the diesel engine was tweaked to 400 hp (298 kW), but the prototype needed 450 hp (336 kW) or more, reported Mazda’s Doonan. Even with the upgrade, which includes Carillo forged steel racing connecting rods, the same Pankl racing crankshaft as was used last year, and a switch to Mahle steel pistons, more than half of the engine’s parts remain stock, including the aluminum block and head. Twin turbochargers from Honeywell Garrett Motorsports replace the factory turbo.

The combustion pressure of the race-tuned engine revealed shortcomings in the racing-spec head gasket the team planned to use. Its unexpected replacement: the standard head gasket installed at the factory on production cars.

As Audi has done with its Le Mans-winning diesel prototype race program, Mazda’s intent is to steer the image of diesel in the mind of the company’s sport-minded customers, letting Mazda sell fuel-sipping diesel cars to customers who prioritize performance.

Honda supplies a race-prepped version of its J35 3.5-L V6 production engine, the HR35TT, or Honda Racing 3.5-L twin turbo, for Daytona Prototype racing by the Starworks Motorsport team. It uses 420 Honda production parts, including the block, heads, crankshaft, and direct fuel injection system. Interestingly, though most of the parts come from the production version of this engine used in the Acura MDX, RLX, and TLX, some parts come from the RDX, the S2000, and even the CBR motorcycle.

Honda Performance Development (HPD) engineers send reports to production engineers if they find any issues in post-race engine teardowns, providing valuable feedback, reported Steve Eriksen, Vice President and CEO of HPD. Sometimes when time is short, engineers from Honda R&D come to HPD to assist in the assembly of the race versions of the production engines for hands-on experience with them, he added.

Chevrolet racing has been developing direct fuel injection know-how with its Indycar racing program that Kent said he hopes will benefit both the IMSA Corvette racers and future production models. In conjunction with supplier Hitachi, Chevrolet racing engineers are experimenting with the location of the direct injector and with the programming of the system so it switches between direct and port injection depending on conditions.

“We are definitely sharing our learnings with the production team,” said Kent.

Ford, like Mazda, has new engine technology it wants to show off, so the company has applied its EcoBoost 3.5-L V6 engine to the Daytona Prototype category. Just as the company is asking its customers to do, Ford has switched from V8 power to the twin-turbocharged gasoline V6 as a fuel-saving alternative.

The racing version of the EcoBoost engine uses about 70% factory original components, including the block and heads, according to Ford Racing spokesman Paul Seredynski.

In some ways, the production engine is actually more sophisticated, because the race engine has been stripped of its variable valve timing, which isn’t allowed under the rules.

In race trim, the EcoBoost engine runs 11 psi of peak turbo boost, which is similar to the boost of the production engine, and it spins to a maximum of 7100 rpm, a bit faster than the production engine’s 6500-rpm redline.

When the Chip Ganassi Racing team switched from V8 power to the EcoBoost turbo V6, it did so for the same reason that F-150 truck buyers make the switch: to save fuel. “It is that fuel economy for endurance racing that was the draw,” said Seredynski.

The race engine started the season at Daytona with a racing crankshaft inside, but the team may switch to the production part. “The Ford part is more durable, but a lot heavier,” he allowed.

If they do, it will just be another piece of evidence to help convince drivers that emerging fuel-saving technologies have a place both in their driveway and on the racetrack.

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