Cutting edge aerodynamics assist in the performance of a car, especially one that is expected to perform at high speeds. So it’s not just Formula One that demands a high degree of air sculpting – even the Porsche Cayenne advertises its aerodynamics as a USP.
You may be forgiven for thinking that the extra bit of performance brought in by a tail spoiler makes sense only on the 911 Turbo – which it does. But the Porsche Turbo is supposed to be Porsche’s Sports car of SUVs so allow them the excitement.
The active rear roof spoiler is one of the differentiators between the S and the Turbo. The S gets a fixed spoiler with just a hint of a duck lip, while the Turbo gets the new flap, electrically driven with a gearbox and reaction times of 0.8 seconds.
The flap operates in one of four positions, almost akin to the way an airplane’s flaps work, although here it does not increase lift. The flap begins with a 20mm open on hitting speeds above 160 km/h with a further 40mm position on selecting Sport Plus mode.
One of the unique features of the adaptive roof spoiler is its ability to factor in behaviour at specific speeds – like if the car is above 250 km/h the flap lowers to reduce drag, rising again once the speed quickly drops to 200 km/h, assuming that hard braking and cornering will need more downforce. The spoiler also adjusts to factor in the turbulence generated above 160 km/h if the panoramic roof is left open, rising to a 50mm open position.
From there it can open all the way to a full-open 80mm position which is effectively an airbrake. The airbrake is able to reduce braking distance by 2 metres from a speed above 250 km/h.
The adaptive roof spoiler thus helps performance with up to an extra 100kgs of downforce on the rear of the Cayenne Turbo.
There’s also an explanation from 25:51 to 29:35 on the video of the Porsche Technical Workshop below: