After a season with an interim car adapted to the new GTE regulations, Porsche has rolled out its all-new, mid-engined 911 RSR for international sports car racing competition next year, in what could be the most radically designed 911 race car to have ever come out of Weissach.
Unveiled at the LA Auto Show earlier this month, the 2017-spec GTE contender has gone though a complete transformation that sees its updated 4.0-liter six-cylinder boxer engine moved forward, ahead of the rear axle, and the gearbox repositioned to the rear of the car.
According to Marco Ujhasi, Head of Porsche GT Works Sport, the extreme makeover, both from a mechanical and aerodynamic point of view, has been made possible due to a clean-sheet design around the FIA and ACO’s new-for-2016 GTE regulations.
“We never looked at all the needs you have to fulfill for racing as [comprehensively] as we did with this car,” Ujhasi said.
“When you are going through all of the points, you come to a point where you say, ‘OK, there is an opportunity from the regulations to optimize your weight distribution and aero figures.’ And then you go for it.”
With GTE regulations not having a specific parameter for engine placement, Ujhasi said they’ve moved the direct-injected powerplant as forward as possible, although not going into specific measurements.
It’s not only created a better weight balance, but has also allowed Porsche to utilize a significantly larger rear diffuser, due to the engine’s relocation.
“It’s all linked together,” Ujhasi said. “If you change the weight distribution you can change the aero. It’s not just a single point. If you adjust one point, you have to readjust all the others and always working in that overall car philosophy.
“The freedom, especially on the aero side came from the freedom with the engine. That was necessary to close up to the other [manufacturers].
“If you look at the Ferrari or the Ford, it’s comparable to them concerning the underfloor. It’s going in the same direction. If you look at the 2016 car, it’s not a real diffuser at the end.”
The engine and gearbox swap has resulted in the first 911 with its transmission at the rear of the car, a move that Ujhasi said was not a difficult one to make, despite some re-engineering.
“It’s a completely new gearbox and doesn’t work with the old one. But it’s not rocket science to do that. Many cars have that,” he said. “The principles are known. It’s all the details.”
The six-speed sequential gearbox now features an electronic shift actuator for the first time, which Ujhasi noted as “definite step forward,” while the wheelbase has been extended by 60 mm to help accommodate the revised engine/gearbox layout.
The other major point is Porsche’s decision to remain with a normally aspirated engine, and not a turbo, as in the case of the Ford GT and Ferrari 488 GTE cars, which dominated this year’s 24 Hours of Le Mans.
“In the beginning, we tried to take all of the points into consideration,” Ujhasi said. “One year ago, it was clearly an advantage from our point of view to stay with a naturally aspirated engine.
“When you are looking at it from an overall car perspective, it’s the better way to go. The Porsche philosophy always was to go in an overall car performance direction, not in a single highlight area.”
Ujhasi noted a number of drawbacks to a turbo, including its increased weight and cooling needs, and remaining a normally aspirated powerplant has enabled Porsche to utilize the same GT3-based engine across all platforms, including the road car, 911 GT3 Cup car, 911 GT3 R and now the new 911 RSR.
While the decision was taken a year ago, Ujhasi believes a more rigid Balance of Performance process, which matches the turbo power curve to a normally aspirated car, will help keep everyone on a level playing field, at least on power output.
“The regulations are built to make that equal,” he said. “Sometimes it works better and sometimes it’s more difficult. We still trust in the capabilities and we will see. For sure we’re not the only one with the naturally aspirated engine. So why shouldn’t it be possible?
“There’s been some steps made, and also lessons learned from this year. We’re quite comfortable it will be at a good level.”
The new 911 RSR first took the track in early March and has since racked up more than 20,000 miles in extensive testing around the world, including a recent five-day endurance test at Sebring, which saw the car run for 50 continuous hours without issues.
Porsche factory driver Patrick Long, who sampled the car for the first time in a three-day test at Portimao, said he felt significant gains in handling over the previous-generation 911 RSR.
“It’s certainly different behavioral qualities but for me the biggest change is the car in the high-speed corners, aerodynamically,” Long told Sportscar365. “The additional work that was done at the rear of the car has paid big dividends.
“I think it’s a step in the right direction. But in this type of motorsport, you’re as good as the regulations allow you to be. But I think there’s been big strides and an exciting time for the 911.”
With a race debut set for January’s IMSA WeatherTech SportsCar Championship season-opening Rolex 24 at Daytona, the question of whether Porsche’s radical new GTE contender still maintains its heritage as a 911 has come up, although has been quick to note the German manufacturer’s past.
“It’s really in the heritage of the 911 because if you remember what our very old boss and founder of the company said, ‘I dreamed of a car and I couldn’t find it, so I decided to build it myself.’ That’s the idea behind it,” he said.
“We have a certain task to solve and material to work with and you make the best out of it. That’s the story of the 911 and we’re staying to that line.”