Porsche's been in the endurance racing game long enough to know that reliability is essential to success. To get ready for the 2017 season, Porsche took its new, mid-engine 911 RSR race car to Sebring for an endurance test. A 50-hour endurance test, to be specific.
In for the 2017 season, Marco Ujhasi, the guy behind Porsche's GT racing program, says no other manufacturer has done such an extensive test. Sebring is a great proving ground for any race car, not only because it's on the IMSA WeatherTech calendar, but because it's an incredibly bumpy, challenging technical circuit. Apparently, Porsche's test went off without a hitch.
"Precisely because of the enormous stresses, it was the right direction," said Ujhassi. At the RSR's debut race, the Rolex 24 at Daytona, the #911 nabbed second place, and both of Porsche's factory entries survived without mechanical setbacks. The RSR got its first victory later in the year at the Northeast Grand Prix at Lime Rock, with the #911 and #912 occupying the top two spots of the podium.
In total, the RSR did around 22,000 miles of testing before its maiden race at Daytona. Porsche says this is the most extensive testing it's ever done on a GT race car.
Of course, Porsche had a lot to test with the new RSR. Moving the engine ahead of the rear axle allowed Porsche engineers to make big aerodynamic changes to the new car, generating a lot more downforce than its predecessor. Part of the RSR's aerodynamic development was undertaken at Weissach's fancy rolling wind tunnel. There, the car rolls on a treadmill-like belt that can simulate different tracks, helping Porsche estimate the lap times the car will run in real life.
The RSR also received a new engine, a 4.0-liter naturally aspirated flat-six with direct fuel injection and a new rigid valvetrain that eschews hydraulic lifters. In race spec, this engine makes around 510 horsepower, depending on balance of performance restrictions. This engine, which is very similar to the unit used in the current 911 GT3 road car, spent 300 hours on Porsche's test bed, including two 70-hour continuous endurance runs.
Porsche only built seven RSRs for the 2017 season—two for IMSA, two for the WEC, and three test cars. More are on their way though, as Porsche has sold six cars to customer teams for competition next year.