While the TUDOR United SportsCar Championship features a dozen automakers, including seven different chassis/engine combinations in the Prototype class alone, there’s arguably only one manufacturer that’s put its development program on public display this year.

After numerous years of success in the GT ranks, Mazda made the bold step up to the prototype ranks for 2014, fielding the first-ever diesel-powered P2 car and the only full-factory team in the championship’s premier class.

The task of competing alongside the conventional and proven DP and P2 packages has been just one of the challenges for the Japanese manufacturer, as the SpeedSource-run operation has faced an uphill battle with adapting its production powerplant for the rigors of top-level prototype racing.

“When the first road car engines showed up in a crate from Japan, I think all of us gasped and looked at what those were,” Mazda Motorsports director John Doonan told Sportscar365.

“We knew their potential, and knew that the machining and tooling on them were probably the best we’ve ever seen from Mazda. But knowing what we were going to ask them to do, it was a bit daunting,”

“Each step of the way, we’ve found the limits and surpassed the limit and tried to find ways to improve. Cooling has been our big issue, without a doubt. We’re asking this entire package to do three times what it’s designed to do in a road car.

“I think the hardest part is being a racer and being patient and not being able to immediately fight at the front. But we cannot forget the story we’re trying to tell. This is a road car engine that’s been asked to do the unthinkable.”

SpeedSource and Mazda have been in a constant state of development with its Multimatic-built Lola-based prototypes, with the focus primarily on cooling optimization for the 2.2-liter SKYACTIV-D powerplant.

A major turning point came at the fourth round of the season at Mazda Raceway Laguna Seca in May, when the No. 70 entry of Tom Long and SpeedSource team principal Sylvain Tremblay finished an impressive seventh overall.

The sister car of Joel Miller and Tristan Nunez, meanwhile, turned laps on par with the P class leaders before being collected in an early race accident.

While the last few rounds have seen further updates to the pair of factory entries, Doonan said the results haven’t necessarily been there to show the improved pace of the package.

“We continue to find ways to cool the car, so we can turn the wick up,” he said. “Obviously the Mazda Raceway event was a huge breakthrough for us. That was a big step for us and I think now there’s a lot of little steps.”

Doonan said one of the short-term goals is to roll out with a redesigned cylinder head, aimed to help improve cooling. Updates to the car’s intercooler, radiators and bodywork have also helped with the persistent heat issue.

Steps are also being made in chassis development, with the goal of creating a Mazda-specific chassis for the proposed new-for-2017 prototype regulations, budget-permitting.

“Multimatic has been fantastic in terms of throwing every resource they have at it,” Doonan said. “They are solely focused, at least on the prototype side, on this program. We’ve got a ton of attention there.

“As we look towards the 2017 regulations, which are being discussed, it’s interesting to try and forecast exactly where that’s going to end up.

“Obviously at Le Mans, we saw several new [P2] chassis, which you would guess they’re aligned with the ’17 rules but they’re obviously 2014 launches.

“We’re trying to be smart. We have an existing package. The engine obviously needs refinement. That’s why we put it into a [proven] chassis.”

If all goes to plan, Doonan hopes to begin customer sales and leases of the SKYACTIV-D powerplant by the end of next year.

However, it could very well be limited to teams in the TUDOR Championship, as diesel-powered engines are not currently ACO approved for LMP2 competition.

“We’ve continued to have that conversation [with the ACO] and I think their direction to us in late 2013 was to come here in ’14 and perform and allow them to collect data and see our progress.

“In our conversations with the [technical staff], they have patted us on the back in terms of what they’ve seen as progress.

“That doesn’t equal allowance to run the engine but it does allow the world to see that Mazda is serious about using top-level sports car racing as a way to showcase road car technology.”

If a return to Le Mans in LMP2 with the SKYACTIV-D isn’t possible, could Mazda look at mounting a LMP1 effort instead?

“With our history there, it’s always a discussion internally,” Doonan said about a return to Le Mans, in general. “It comes down to finding the right place, budget-wise, and finding the right story to tell with our production engines and our vehicle platforms. There’s a lot of unknowns.

“Frankly, to have won the race overall, you always want to think about going back there and trying to repeat that. But a pretty lofty target has been set by those who are competing there [in LMP1] right now.

“I don’t think it’s ever ruled out. Anybody at Mazda is always looking for the next challenge and dreaming of what it can be. We just have to keep our eyes on the best way to tell our story… and be able to pay for it!”