The heart of a Porsche beats right behind the driver: the free-breathing 4.0-litre flat-six engine is mounted between the seats and the rear axle, making the new 718 Cayman GT4 RS the most powerful sports car in the history of the popular mid-engined range. The new car boasts the kind of figures usually only seen with racing cars: 500 PS (368 kW) of power at 8,400 rpm, 450 Nm of torque at 6,750 rpm and a maximum engine speed of 9,000 rpm. Indeed, this engine really is used in motor racing: in the Porsche Mobil 1 Super Cup, the Porsche 911 GT3 Cup will compete with the same engine with almost identical performance data. And the road-approved 911 GT3 model is also equipped with the same high-revving engine. The naturally aspirated flat-six responds eagerly to the accelerator pedal and catapults the Porsche 718 Cayman GT4 RS to 100 km/h in just 3.4 seconds. The 200 km/h mark is reached after 10.9 seconds, and acceleration continues right up to a top speed of 315 km/h. Average fuel consumption is 12.3 l/100 km as per NEDC and 13.2 l/100 km as per WLTP.
Engine technology derived directly from racing
The engine of the GT4 RS is a prime example of technology transfer from motorsport to series production. For example, the 24 valves of the six-cylinder engine are actuated by rigid rocker arms that do not require hydraulic valve clearance compensation. This ensures the robustness of the valvetrain even in the harshest of conditions – even if the engine is frequently run at high rpm. In addition, the proven VarioCam technology ensures that the camshaft control is adjusted precisely to the engine speed and load conditions.
The idea of an individual throttle body is also derived from motorsport. Each of the six cylinders has been provided with its own individual throttle body at the end of the variable resonance intake system. It is particularly close to the intake valves and improves the air supply as well as the precision of the fuelling and therefore the engine response. The engine responds to throttle input almost without delay because there is hardly any volume of air between the throttle valve and the intake valves – this applies equally to pressing the accelerator pedal as it does to lifting off it. The central throttle valve remains as a backup solution, but is permanently open during normal operation.
Given the high degree of longitudinal and lateral forces produced by the new 718 Cayman GT4 RS, the oil supply to the high-revving engine is of particular importance. Like in motorsport, this is carried out by a dry-sump lubrication system with a separate oil tank. With a total of seven suction stages, this system routes the engine oil back into the external reservoir quickly and efficiently, while the heavily loaded connecting-rod bearings are lubricated directly via the oil pump through the crankshaft.
Innovative process air routing
Instead of the two rear side windows, the 718 Cayman GT4 RS has additional air intakes that supply the engine with process air. The air from the left and right enters straight into a central airbox, which sits behind the driver and is visible from the outside through the rear window. The result is not only a particularly athletic look but the intake noise of the engine can also be clearly heard by the driver and passenger as the airbox is right at ear height. This soundtrack, which varies considerably depending on load conditions and the engine speed, is rounded off by the lightweight stainless steel sports exhaust system, which shows off the distinctive tones of the car’s flat six, especially at high rpm. At the same time, the GT4 RS complies with the current Euro 6 emission standard. Two separate gasoline particulate filters (GPFs) as well as a stereo Lambda control circuit for both catalytic converters, are responsible for carrying out the all-important emission-control functions.
Optimised PDK transmission with multiple manual options
Like every modern RS model, the new 718 Cayman GT4 RS is exclusively available with the Porsche dual-clutch transmission (PDK). PDK allows gearchanges to be made in the same way as in racing: within milliseconds and without interrupting the engine’s drive. In the GT4 RS, the PDK has seven short-ratio gears and no overdrive function. Top speed is reached in seventh gear.
In PDK Sport mode, downshifting when braking is more instantaneous and acoustically prominent; during acceleration, the upshift points occur at higher engine speeds. If you do not want to leave shifting to the electronic system, you can also change gears via gearshift paddles on the steering wheel. The right paddle is responsible for upshifting and the left paddle for downshifting. The driver gets precise feedback from the shift action even when they are wearing racing gloves. In addition, a selector lever in the centre console can be used to shift sequentially. The lever was adopted from that of the current 911 GT3 and is visually similar to a gated manual gear lever. As is usual in motorsport, the lever is pulled backwards for upshifting and pushed forward for downshifting.
Faster on the Nordschleife than the 718 Cayman GT4 by 23.6 seconds
The new 718 Cayman GT4 RS has already left its mark on the world’s longest and most difficult circuit. Brand ambassador and development driver Jörg Bergmeister lapped the 20.832 km Nürburgring-Nordschleife circuit in a lightly disguised production car in 7:09.300 minutes. The GT4 RS completed the shorter 20.6 km lap, which previously served as the benchmark, in 7:04.511 minutes – 23.6 seconds faster than its sibling, the 718 Cayman GT4. To protect the driver, the mid-engined sports car was equipped with a racing seat. Optionally available Michelin Pilot Sport Cup 2 R tyres were also fitted. An official confirmed the standard condition and weight of the car.
