Sure, the race car starts off on the same production line as more humble Caymans, but it heads towards the world of Porsche Motorsport rather early on. A roll cage is welded in. Sound deadening and carpet are ditched. The GT4 road car’s manual gearbox also fails to make the cut. Instead, Porsche fits a PDK dual clutch automatic gearbox similar to that of the base Cayman, but it loses seventh gear and gains a bespoke mechanical limited-slip differential. Finished cars are then shipped to Nürburgring-based Manthey Racing for final race prep, optional extras like air jacks and a shakedown run on the grand prix circuit.
Our shakedown run was at the safe but challenging Gingerman Raceway in south-west Michigan, the maiden test on US soil for this privately owned GT4 CS. The lack of a removable steering wheel and the beefy FIA-spec roll cage make climbing aboard the mid-engined Porsche a touch tricky. Once inside, a Recaro racing seat secures your anxious body, while the Alcantara steering wheel adjusts for both height and reach, a rare treat in a race car.
The 380bhp engine ignites into a symphony of commotion. You can’t miss the distinctive rap of the direct-injection fuel system, and drivetrain vibrations from the rigidly mounted engine and gearbox radiate through your body. Once on the track, we juggle swapping gear ratios between the 911 GT3-sourced transmission selector and the extremely tactile paddles. The PDK gearbox is an ideal fit for the GT4 CS, but its leggy ratios annoy, just as they do on many Porsches outside of the 911 GT3/GT3 RS. Speaking of the GT3, the GT4 CS carries a distinct shortage of engine sparkle compared with its higher strung siblings. Its 40kg weight loss over the road car helps slightly, but the big story with the minimalist Cayman is very much the chassis.
We ran the fully adjustable GT4 CS in Porsche’s as-shipped chassis set-up. Clearly, either Porsche or Manthey Racing is deathly afraid of understeer. They also didn’t feel the need to make adjustments for circuits that are less smooth-surfaced than a snooker table, it would seem. At Gingerman, the Cayman’s GT3 Cup-derived suspension found track surface imperfections we didn’t even know existed, pitching the car and compromising lateral grip. At lower speeds, it’s mostly just annoying. At higher speeds, impressive car control skills are mandatory. Even with the superb, race-tuned stability control, you can get in trouble. You’re welcome to guess how we know that. Word from the racing paddock is that we’re not alone in our critique of the default chassis settings.