We need to talk about aerodynamics. If you’re intent on building a road-legal track car, aero is now your key battleground. And the Porsche 911 GT3 RS is your key target. This car develops more than twice the downforce of the RS that immediately preceded it, and three times as much as the regular GT3. It has a Masters in airflow management and PHD in drag reduction. In total it develops 409kg of downforce at 124mph, and 860kg at 177mph.
Here’s how it does it.
Weirdly, it all starts here: under the carbon bonnet. In every other 911 there’s a load bay, here it’s made way for a radiator. This is something Porsche has already done with its race cars such as the RSR and GT3 R, as replacing three small radiators with one huge one has allowed aerodynamic elements to be incorporated in the freed up space.
Such as this. OK, so you can’t see through the front of the car, but there used to be radiators below those small light bars. With them gone, Porsche could incorporate an active aero (there’s an acronym: PAA is Porsche Active Aero) system at the front axle. Moveable flaps leading into the front wheel can be rotated more than 80 degrees in just 0.3 secs to provide extra downforce.
There’s something else you can’t see here as well. The suspension arms are wing-profile and at top speed add another 40kg of downforce.
More air coming into the front wheel arch would build more pressure, so larger vents were needed to evacuate it.
In fact, so critical was the airflow and pressure build up in that area, Porsche redesigned the whole door area, cutting it in behind the tyre. A vertical deflector was then fitted to ensure air leaving the wheelarch was channelled down the side of the car, helping to reduce turbulence. There’s a similar one aft of the rear wheels as well, helping the air detach from the car more smoothly.
And that’s not all that’s going on underneath the front. Have a close look at this. No, not the smoke pouring off the back tyres – that was me getting carried away – but the little vents and flicks underneath. They’re designed to channel the airflow under the car in particular directions, often to aid brake cooling or simply get rid of it to increase downforce by reducing underbody pressure.
Meanwhile, back on the bonnet, hot air from the radiator is thrown up through the mesh. The vanes are designed to twist and push it across the bonnet so it exits to the side, rather than going up over the top.
That’s because the engine wants cool air rather than warm air. You see that little bar on the roof silhouetted against the sky? That’s there to prevent hot air coming back up the sides and mixing with the cool air the engine feeds best on.
Engine air goes in here, on the back deck, under the wing. The side intakes on the rear arches are only for extra cooling, mainly for the brakes.
Ah yes, the rear wing. How Porsche got this through regulations is a mystery. We thought any wing taller than the roof and wider than the glass area was a no-no. Pedestrian safety and all that. Porsche clearly knows better than Top Gear. This is hardly surprising.
It’s a swan-neck wing, which means the wing dangles from its supports rather than sitting on top of them. This is because it’s the lower surface of the wing that often generates the most downforce so needs to work as efficiently as possible. In total, the wing area is 40 per cent larger than on the last gen 991 GT3 RS.
Close up of the wing’s active function, a hydraulic piston that activates the DRS (Drag Reduction System for anyone who’s never watched F1). This opens the wing’s upper element to allow air to pass through, reducing downforce by 30 per cent. You can activate it via a button on the steering wheel, but it also operates automatically when certain parameters are met, including being above 62mph and using at least 95 per cent of the throttle travel.
The rear diffuser is one of the few bits that hasn’t been adapted much from the GT3. But of course the 911’s engine position means it can’t have much of a diffuser to create downforce from negative pressure. What next? Mid-engine 911 a la RSR racer? If Porsche wants to take the GT3 RS one step beyond, that could be the logical next step…
Add all this up and what have you got? A GT3 RS that’ll stay stuck to the tarmac, come what may. This shot was taken with the car doing 106mph over GotlandRing’s jump. Compare and contrast with the next image in which the 911 Dakar was travelling at about 92mph…
I know, right? That’s air in action and downforce showing what it can do.
Keyword: Here's how the aero works on the Porsche 911 GT3 RS