Porsche reprises arguably the finest drivers’ car of its generation, with an all-new engine but the same purist philosophy
You’re looking at the second-generation Cayman GT4, and therefore your new departure point into the big-winged world of Porsche’s quickest and sweetest creations.You’ll remember the old Cayman GT4. It was the first time the brains behind the 911-based GT3 and GT2 specials were allowed a proper go at a mid-engined model, and they built near as dammit the perfect driver’s car. Naturally, the basic recipe has hardly changed. The front axle is still taken wholesale from the GT3, though the 20in wheels are unique to the GT4. At the rear the architecture is again largely carried over from the common Cayman, though the dampers are inverted in true motorsport style and the control arms and subframe are pure GT3.It goes on: the engine remains paired to a six-speed manual gearbox and drive is delivered to the rear wheels alone through a mechanical limited-slip differential. You still get semi-slick tyres in the form of Michelin’s Pilot Sport Cup 2, and a huge rear wing, though the new item makes a fifth more downforce than before and works in tandem a pretty beastly diffuser carried over from the GT4 Clubsport racecar. In fact aero is a significant element of the new Cayman GT4, which can somehow lap the Nürburgring quicker than the Carrera GT ‘super sports car’ did back in 2004. ‘Progress’ hardly does it justice.And there’s a different sort of progress in the engine bay: an even better sort. At one point Porsche toyed with the idea of equipping the Cayman GT4 a highly tuned version of the downsized 2.0-litre turbo flat-four found in everywhere else in the Cayman range. In Zuffenhausen they correctly decided that wasn’t good enough, and so the new car gets an evolution of the 3.0-litre engine found in the current 911, only with the turbochargers sidelined and the cylinders substantially bored and stroked out. You read that right.The new 9A2 Evo unit is a 4.0-litre flat-six that spins to 8000rpm, making 414bhp and 310lb ft along the way – an improvement of 34bhp over the old GT4, though torque remains the same. It gets a forged steel crank, hydraulic valves and Piezo fuel injectors, which improve propagation by making three individual – and presumably obscenely rapid – squirts for each stroke of the piston. Porsche can get the system working at 8000rpm but not at 9000rpm, which is why the 4.0-litre engine in the upcoming new GT3 won’t have it, and elsewhere there are low-friction roller cam followers instead of tappets. Below 3000rpm this engine can also shut down a bank of cylinders for better fuel economy. Cleverly, it switches banks after a short while to keep the catalytic converters hot and operational.
Source: Autocar
