The Porsche Cayman GT4 and GTS 4.0 both feature a naturally aspirated flat-six cylinder engine. They both have PDK and manual transmissions offered. And in this case, they’re both the same shade of blue. But there are actually dramatic differences in terms of how these cars perform, much of which might be overlooked by the naked eye. The aerodynamics of the GT4 are all about downforce, while the GTS 4.0 is all about minimizing lift. The GT4 has an upgraded chassis, suspension, wheels, tires, engine tune, and many aerodynamic changes to maximized downforce and minimize drag. Part of the solution? A dimpled underside, similar to that used on a golf ball!
On a golf ball, these little dimples cause turbulence, meaning little pockets of swirling air, so instead of a laminar boundary layer, you have a turbulent boundary layer. In this case, the turbulent boundary layer stays attached to the golf ball longer, wrapping around the ball, meaning the wake behind the golf ball is smaller when the airflow detaches from the golf ball, and a lower pressure region forms. With a smaller wake, the ball has less drag, and thus can travel farther. Porsche says the same logic applies to the GT4, in their words: “At the front end, the special surface on its underside is dimpled, reminiscent of that of a golf ball. As a result, the airflow follows the contour more precisely, reducing drag.”