Porsche’s experience in GT racing leaves no doubt that any new car it brings out will be successful. Its previous iteration of the 991-based 911 GT3 R won on its debut in World Challenge in 2016 with Patrick Long at the wheel. The first generation of the Cayman GT4 found success in the GTS class, primarily in the hands of Rodrigo Baptista for Flying Lizard Motorsports. For 2019, Porsche has both an updated version of the 991 GT3 R and a new GT4 racer in the 718 Cayman GT4 Clubsport MR (pictured above), the latter taking two victories in the season-opening rounds of Pirelli GT4 America SprintX at Circuit of The Americas in the hands of two different teams.
The 718-based racer has proven an immediate hit among GT4 America teams, occupying a good portion of the grid. The car makes some pretty big steps from its predecessor, most not visible to the eye.
“We learned a lot with the first generation,” says Dr. Daniel Armbruster, Porsche Motorsports North America president and CEO (pictured at left). “Based on this experience and knowledge, it was quite an easy process to develop the second generation. For example, the first generation was very close to the street car, especially the overall electronics, and that sometimes causes difficulties because street-legal electronics are highly complex. During the season we found that for racetracks with lots of banking, for example, we had to adjust. With the second generation we knew exactly where the potential of the car was, and from there we adjusted the electronics. The electronics are much closer to the [911 GT3] Cup car electronic platform. That helps us get a more bulletproof system more dedicated for the race applications.”
Much was made after the car’s introduction of the alternative door material used in the 718 Cayman GT4: hemp. Armbruster says it has similar strength and weight to carbon fiber, but is a more sustainable material. He also says that Porsche developed new methods of carbon fiber production for the car that can carry over to future road cars.
The 3.8-liter flat 6 engine that produces 425hp (40 more than its predecessor) and 6-speed PDK gearbox are essentially the same as the old GT4 Clubsport MR. “It’s a little bit tuned horsepower-wise and also the torque application is a little bit changed,” Armbruster adds. “But in general it’s a carryover from the street car, and that’s our strategy — to keep those very cost-intensive areas as close as possible to the street car. It’s still service free, so you don’t have to do any engine or gearbox service, even at the end of the season. That should be the core of GT4: a very good entry level for the customers, just go racing with the car.”
Porsche aficionados will note that there is not a flat 6 engine anywhere in the 718 line-up, which is all turbocharged boxer 4-cylinder engines making from 300hp to 365hp. And while the previous generation Cayman featured a GT4 road-going model, there is no such beast in the current model line. As Armbruster notes, in this case the race car precedes the road car, and while he wouldn’t comment on future models, he did note that Porsche worked hard to keep the GT4 Clubsport MR under wraps until its unveiling earlier this year . He also said that there are many parts on the race car he can’t talk about because of their planned use on future road cars.
While the 718 Cayman Clubsport MR is based on the latest generation of the Cayman platform, the same is not true for the evolution of the 911 GT3 R. Based on the 991.2 platform (as are the current GT3 road cars) as opposed to the just-introduced 992, the car has evolved significantly from the one introduced in 2016, thanks in many ways to the 911 RSR GTE /GTLM race car.
“We have a very good picture where you can see all the carryover parts from the former generation to the new one, and it’s less than 20 percent. The car is changed in nearly every single part, but in general it’s more of an evolution, not a revolution. The car is much closer to an RSR; we took a lot of concepts and ideas and functions from the RSR and implanted them into the GT3 R,” Armbruster explains.
That includes how the body panels are assembled and disassembled in order to aid serviceability, and also the front suspension, which is now a double-wishbone design that makes setup changes easier. Those two design elements work in concert; pull off the front fenders, and the crew has direct access to the suspension. Easier to work on and, in a sense, easier to drive were the engineering briefs in developing the new GT3 R.
“Our focus on improving the performance was in improving the driveability of the car. The consistency over a stint is much more predictable and the tire degradation is in a smaller window. The aero balance was improved, and the engine was a little bit changed in the direction of more torque in a wider window. It’s more predictable for the driver.”
That should perhaps make it more appealing for Pro-Am and Amateur competitors, where lately teams have drifted toward other marques that are perceived as more friendly to the gentleman driver. There were seven 911 GT3Rs at COTA, four in the hands of Pro-Am or Am teams. Wright Motorsports posted the best result for Porsche, finishing third with Patrick Long and Scott Hargrove.
The 718 Cayman GT4 Clubsport MR sees Pirelli GT4 America action next on the streets of Long Beach, when the Sprint series has its third round of the season April 12-14.