Why the Porsche 911 RSR Had to Go Mid-Engine – Road & Track

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Going mid-engine breaks with years of 911 tradition, but it was a necessary step.
The word radical is overused to the point that it’s lost its meaning, but there are few better words to describe Porsche’s new 911 RSR. For the first time in the 911’s 53-year history Porsche has moved the engine ahead of the rear axle, abandoning the car’s most defining trait. Yes, Porsche campaigned a mid-engine 911 GT1 between 1996 and 1999, but that was a 911 in name only.
The new RSR, however, is an honest-to-goodness mid-engine 911. We covered the details of the 911 RSR when it was first announced earlier this month, but to get even more info, we caught up with Porsche Motorsport boss Frank Walliser at the Los Angeles Auto Show. Interestingly, ideas for a mid-engine 911 racer had floated around Porsche since 2004, but the company got serious about doing it a decade later.
When I took over Motorsport in 2014, there had already been some studies for, let me say, optimized weight distribution,” said Walliser. “In March 2015, we made the final decision with the board and everything–the concept was there, and we did the studies, then we started with the engineering.”

Given that the RSR was such a significant break from tradition, coming to the final decision wasn’t entirely painless.

If somebody comes and says, ‘I have a super idea–I’ll change the 911!’ normally you hear the ‘no’ before you have finished your sentence,” said Walliser. “But, we worked with the company on the analytic side,and we worked very closely with the press and the marketing departments.”
Going mid-engine was seen as a necessary step for the RSR to remain competitive in WEC’s LMGTE-PRO and IMSA’s GTLM classes. Both classes are ruled by Balance of Performance (BoP), which attempts to evenly match the power-to-weight ratios of each car using air-intake restrictors and ballasts. In theory, this leads to close racing between a host of different cars, but in practice, it puts Porsche at a disadvantage.
With power and weight largely out of the question, aerodynamics and weight distribution become the two most important variables on a GT racer. Ford cleverly used BoP to its benefit with the new, mid-engine GT, which has an optimal weight distribution and the most advanced aerodynamics in the GT field.

The 911, on the other hand, has a disproportionately large amount of weight on the rear axle, contributing to compromised handling and increased rear tire wear. Having an engine in the back also gets in the way of running a larger diffuser, like the Ford GT and Ferrari 488.
Switching to a mid-engine layout is Porsche’s way of leveling the playing field, even if it loses its rear-engine traction advantage.
It was clear for us that we give up our weight advantage, but we gained the advantage of the aerodynamics and the weight distribution,” said Walliser. “Yeah, we gave something up, but we gained more on the performance side.”
“Aerodynamics, weight distribution, inertia. All these things are optimized,” said Walliser.

You might wonder–as I did–why Porsche went through all the trouble to build a mid-engine 911, when it already has a mid-engine GT racer in production, the Cayman GT4 Clubsport. I asked Dr. Walliser if there was any thought towards creating an LM-GTE-spec Cayman.
“Not really,” he replied. “As we’ve always said, ‘it’s the 911.'”
It was previously believed that Porsche was granted a waiver to build a 911 that differed so drastically from the street car, but that’s not the case.
It’s not a waiver,” said Walliser. “It’s written in the rules of GTE that you can do that. As long as you stay on your platform, no problem.”
“So as long as it’s a 911. . .”
“No discussion,” replied Walliser.

This seems crazy until you realize that most front-engine GT racers do virtually the same thing. Both of the RSR’s front-engine competitors, the Aston Martin Vantage GTE and Chevrolet Corvette C7.R, have engines pushed further back in the chassis for better weight distribution.
Bearing this in mind, Porsche’s decision to go mid-engine with the RSR feels like playing catch-up rather than leapfrogging the competition with a wild new design. It’s a reflection on the state of top-level GT racing today.
“If you ask me, [LMGTE and GTLM are] tougher than the Prototype category,” said Walliser. “It’s the pinnacle of GT racing. It’s Ferrari, Corvette, Aston Martin, Ford, Porsche, and soon, BMW. . . It’s highly, highly professional.”

Of course, going mid-engine won’t solve all of Porsche’s problems. The team is fielding a virtually brand new car, and as such, it faces many uphill battles in 2017. Making matters worse, the RSR’s first two races are among the toughest on the calendar, the 24 Hours of Daytona and the 12 Hours of Sebring.
“Target number one is to survive the long-distance races, and to have a good feeling on everything,” said Walliser. “It’s every detail–every screw, every bolt must work, and we’re testing like hell. Finally, you know it when you’ve finished the race.”
When I add that Daytona is a baptism by fire, Walliser replied, “better Daytona than Le Mans. Even, Sebring. Sebring is even harder.”

Walliser doesn’t see an issue with fan reactions, however. Even though the RSR breaks a key 911 tradition, Walliser argues most won’t care.
“At the end of the day, they want to see their brand winning,” said Walliser. “Number one is winning; number two is Porsche; number three is 911, and then it’s maybe ‘where is the engine located?’ But if you win, nobody will care.”

“And I always say, ‘when the car is successful, the technology is sexy.'”
So what’s Porsche’s biggest challenge, then?
Management of expectations,” Walliser said, with a laugh.


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