The GT4 development team made one critical decision—to give the car an engine from the mainstream side of the Porsche business. In this case, the 3.8-liter flat-six from the 911 Carrera S. Doing this enabled money to be spent on other areas, including giving the Cayman many of the same suspension components as the current 991 GT3. But it does mean an engine that, on paper, lacks some of the high-revving Götterdämmerung we’ve come to expect from a GT-level Porsche.
Just getting the engine into the Cayman required some engineering gymnastics, including turning it 180 degrees so it sits on the other side of the rear axle. Exhaust and intake systems are necessarily new, but the internals are unchanged, and the only other alteration is a lighter flywheel. Officially the GT4 has 385 horsepower—45 more than the Cayman GTS but 15 fewer than the same engine in the 911. But we’ve been assured that output figure represents the very least number of horses any GT4 will ever deliver, likely while climbing a mountain on a hot day.
Also published on Medium.