Explaining The Science Behind The 718 Porsche Cayman GT4 RS's Split Side Intakes

The Porsche Cayman GT4 RS engine necessitated some compromises but also made up for them

The Porsche 718’s engine bay is a tight squeeze even for the iconic, Porsche boxer engine. The GT4 RS is the only Cayman to feature the GT3 engine. The naturally-aspirated 4.0-liter flat-six fitted in the regular 718 GT4 is, actually, a different engine, derived from the 992’s 3.0-liter twin-turbo flat-six (minus the turbos).

The GT4 RS features the largest, most powerful engine of the whole 718 lineup, but it comes at a cost. For packaging reasons, both, the front and rear suspension of the GT4 RS feature McPherson struts, which in theory, reduces the maximum mechanical grip available.

To offset this, Porsche has made changes to the suspension and chassis. The GT4 RS features increased nominal camber by 0.25 degrees, revised shocks and spring rates, different ball joints, and the entire front body section from the 991 Carrera 4S. Other enhancements include extensive use of carbon-fiber and aluminum body panels and a revised underbody for maximum downforce.

The GT4 RS features unique air intakes

Among the many unique features of the Porsche Cayman GT4 RS are the air intakes, integrated into the rear side windows. This is the only Porsche 718 to have them and is also the only 718 to have dual air intakes with one air filter for each side. The airbox also shares air space with the driver since it is technically behind the rear seats (where the engine is). This enhances the sound greatly while focusing on the 400 Hz sound frequencies that make for a unique soundtrack.

The only downside is that, at low speeds, some droning can be expected, but there is a quick fix for that – just drive fast. The GT4 RS’ symmetrical air-intakes are mounted higher than in other models, which should mean colder air goes into the engine. The Weissach package also comes with larger, more pronounced air intakes. The carbon-fiber air box is not that dissimilar to what you see on the Lexus LF-A.

The Cayman GT4 RS has the same engine as the 911 GT3, but with less power

You may have noticed that the Porsche Cayman GT4 RS has 10 less horsepower than the 992 GT3 (502 horsepower), despite featuring the same engine. That’s because the flat-six was originally meant for a rear-engine layout and had to be turned 180 degrees. This caused the need for longer exhaust piping, hence the reduction in power.

Porsche is, often, downplaying its numbers, as seen with the 911 992.1 Carrera, which turned out to be a lot more powerful. While a longer exhaust tract would explain the power difference, it could also be Porsche’s way of ensuring the 911 GT3 stays on top of the model hierarchy. With the Weissach package adding larger air intakes, is it possible the Cayman GT4 RS makes more power than advertised?