One of the most surprising things about is the material it uses for its doors and wing. At a quick glance it looks like carbon fiber, but it's not. Instead, Porsche is making these parts from what it's calling "natural fiber."
What is natural fiber? It's a material made primarily from flax. Yes, that flax—the same plant that produces edible seeds and whose fibers are used to make linen. And now, race car parts.
So what's the point of developing a new material that serves the same function as carbon fiber? Sustainability. At the Daytona reveal of the new GT4, Eduard Ene, Porsche Motorsport's composites expert, told us that producing the raw materials to make natural fiber takes 75 percent less energy than carbon fiber. Ene also pointed out that natural fiber can be ground down to be reused for different purposes, whereas carbon fiber needs to be burned at a very high temperature to be disposed of.
There are functional benefits, too. Carbon fiber is a very strong material, but when it breaks, . This natural fiber, according to Ene, has five times better vibration dampening properties than carbon fiber, so it doesn't splinter when hit hard. On the race track, that's great because it means there's less cleanup after an accident.
Porsche showed off a few different ways to make this material, including natural fiber reinforced plastic—which is very similar to carbon fiber reinforced plastic—and a natural fiber sandwich, which uses a balsawood core. These woven materials are pressed into shape using the same methods used to make carbon fiber parts. The doors on the new GT4 are made using a resin transfer molding process while the wing is made with a pre-impregnated process.
The doors weigh 11.2 pounds, making them a little heavier than the 9.9-pound carbon-fiber doors used on the previous Cayman GT4 Clubsport. The wing on the new car weighs 8.6 pounds, but since it's significantly bigger than that of previous GT4, there's no direct weight comparison.
And while natural fiber has superior vibration dampening properties, it's not nearly as strong as carbon fiber. It can only be used for the doors in the 718 Cayman GT4 Clubsport because there's a roll cage in place to ensure driver safety. That's why you won't see these doors in .
Ene said that natural fibers could be used to make non-structural components in a production road car, like fenders, hoods, or wings. Porsche wants to do this eventually, but it's a little ways off. The company started with the 718 Cayman GT4 Clubsport because production is fairly limited and the visual finish of the components doesn't really matter as they're just going to get liveried up anyway.
Despite using a lot less energy to produce, natural fiber is still more expensive than carbon fiber, but that could change as the material is developed further. That development already started this past weekend, as a squad of 718 Cayman GT4 Clubsports hit the banks of Daytona in testing for the four-hour BMW Endurance Challenge later this month. These new GT4s will be racing all over the world this year, putting this new material to the ultimate test.