Most powerful, dynamic and comfortable: the latest 911 Turbo S sets new standards in many areas. This also applies to adaptive aerodynamics, which Porsche has further improved for the flagship version of the 911. Active aerodynamics (PAA – Porsche Active Aerodynamics) now adapts the car's aerodynamics even more precisely to the road situation, speed and selected driving mode. PAA celebrated its global debut with the previous generation 911 Turbo launched in 2014. Active aerodynamics is now available across all model ranges, from the 718 to the Panamera and Taycan models.
Porsche 911 Turbo S
“No other sports car responds to the different situations with the aerodynamic flexibility of the new 911 Turbo S. As aerodynamic engineers, we are usually faced with a dilemma: high top speed and low fuel consumption benefit from a low drag coefficient, while driving dynamics benefit from high contact pressure. But these are contradictory traits,” explains Dr. Thomas Wiegand, Director of Aerodynamic Development at Porsche. “PAA resolves conflicts between these interests. The comprehensive extension of the intelligent system on the 911 Turbo S allows for a much wider range of aerodynamic configurations for optimum driving dynamics and minimum drag. In addition, aerodynamic components have great potential to support specific driving dynamics requirements – in all driving situations.”
New are the active cooling air flaps. As a result, in combination with a movable front spoiler lip and a retractable and tiltable rear wing, the new top model has three elements of active aerodynamics. In addition to the main aerodynamic configurations, the 911 Turbo - PAA Speed (speed) and PAA Performance (performance / efficiency) - also allows the implementation of the Eco configuration.
PAA has also been improved with a Wet Mode feature that shifts the aerodynamic balance towards the rear axle for greater driving stability in wet conditions, and an Air Brake feature that increases drag and downforce in the event of full braking at high speed. The result: shorter stopping distances and improved driving stability. PAA also responds to changes in airflow around the vehicle when the sunroof or convertible roof is open. This means that there are eight different aerodynamic configurations in total, each with a specific combination of active components.
Improvements have been made not only to adapt the aerodynamics to specific driving requirements, but also to the aerodynamics itself: a redesigned front spoiler and rear wing have increased downforce on the 15%, providing better stability and driving dynamics at higher speeds. The maximum downforce in the Performance position (Sport Plus mode on) is now around 170 kg.
The drag coefficient (Cd) of the 911 Turbo S depends on the aerodynamic configuration. The most efficient, with a minimum Cd value of 0.33, is achieved with flaps closed and spoilers folded (front and rear).
Cooling air dampers: infinitely adjustable
The newly developed movable cooling air dampers reduce running resistance and thus reduce fuel consumption. The dampers are located on the right and left air intakes of the front bumper. They are infinitely adjustable and control the supply of cooling air to the radiators.
The intelligent energy management system is responsible for striking a balance between the actual cooling demand, the amount of electricity needed to operate the radiator, and the aerodynamic benefits of the damper settings. As a result, from a forward speed of 70 km/h, the cooling air flaps close to the maximum. This has advantages in terms of fuel consumption in everyday driving.
From 150 km/h the flaps open linearly to achieve optimum aerodynamic balance at high speeds. Priority is also given to driving dynamics – for this reason, the cooling air flaps open when the Sport, Sport Plus or Wet modes are activated, as well as when the driver switches off Porsche Stability Management (PSM) or presses the spoiler button.
Front spoiler: pneumatic adjustment of individual segments
The active front spoiler of the 911 Turbo has also undergone significant changes. Compared to its predecessor, its effective airfoil has increased and the extension or retraction is now faster and at lower pressure. The three segments are individually controlled by actuators. The two external drives always work in sync. The front spoiler is made of flexible plastic (elastomer), so the middle segment can be folded or extended when the outer ones are already extended. There are several ways to adjust it:
- In the basic position, the spoiler is completely retracted and is in position thanks to elastomer pretensioning and magnets on the 911 Turbo S running gear.
- In the “Speed” position, only the two extreme segments are extended. The result: more air flows around the body and front axle lift is reduced.
- In the Performance position, all three segments are expanded. This position provides performance-oriented aerodynamics with the highest possible downforce at the front axle. In this position, the "911 turbo S" logo is visible, embossed in the center of the spoiler.
The control unit and compressor were mounted on the side of the trunk. Since the pneumatic module is more compact than its predecessor, the luggage compartment volume has increased by 3 liters. The movable front spoiler also increases the angle of attack, enhancing the usability in everyday life: in the basic position, the ground clearance is higher, making it suitable for parking or maneuvering speed bumps.
Rear fender: now with even more features
The rear wing is Turbo's calling card and is lightweight. It weighs 440 grams less than its predecessor, but its effective area is 8% larger. The base of the wing is a foam core with forged inserts. The leaf structure consists of an upper side with two layers of carbon fiber reinforced plastic (biaxial CFRP fabric) and a bottom side with one layer of glass fiber reinforced plastic (triaxial GFRP fabric). The electrical adjustment of the sash, which can be folded and tilted, is mainly carried out depending on the speed and the selected driving mode.
Depending on the driving mode, in addition to the well-known items "Speed" and "Performance", additional items are available:
- The Eco position with retracted wing is now available in a wide range of speeds - then the car shows minimal resistance.
- Performance II, with a reduced angle of attack, at speeds above 260 km/h reduces drag and reduces the load on the tires of the rear axle, thus avoiding the increase in tire pressure. As a result, tires have great potential in terms of longitudinal and lateral dynamics in terms of performance and especially sporty driving, for example on racetracks. Proper tire pressure adjustment also has a positive effect on daily use and driving comfort.
- In another new position - Wet - the wing is significantly extended, but not tilted. When the Wet mode is selected in combination with a fully retracted front spoiler, the aerodynamic balance shifts towards the rear axle. The result is more rear-end stability and increased driving stability, resulting in a higher level of safety on wet surfaces.
New features: wet mode and air brake.
The new Wet mode emphasizes driving stability in wet conditions. If the sensors fitted as standard in the front wheel arches detect a very wet surface due to spray liquid, a message will appear in the instrument cluster. The driver can then manually activate Wet mode using the rotary switch on the steering wheel. In addition to the adaptation of the aerodynamic elements described above, all relevant vehicle controls are also adjusted to achieve maximum driving stability.
Another new feature is the air brake, which is automatically activated in the event of full braking at high speeds. The front spoiler and rear wing occupy the Performance position. Increased drag and increased downforce can shorten your braking distance. Braking stability is also improved.
Control strategy: wide aerodynamics
The PAA control strategy when pressing the spoiler button is the same as in Sport Plus mode.
In addition to the basic positions described, PAA also responds to the opening of the sliding or convertible roof. Thus, there are seven positions of the rear wing. The different equipment options are also taken into account in the configurations of the individual elements.
In addition, the steering strategy determines whether the vehicle is a coupé or convertible and whether Sport Design elements with different body contours are fitted front and rear.
Porsche Aerodynamic Innovation
For generations, Porsche has consistently improved the 911's aerodynamics. What's more, the sports car manufacturer has set the pace in aerodynamics on many occasions. Here are his most important achievements:
- As early as 1971, Porsche installed the first front spoiler on the 911 S. This accelerated the flow of air under the car and made it possible to direct part of the flow to the sides, thereby reducing the phenomenon of front axle lift.
- 1972 was a milestone in the development of aerodynamics: the Carrera RS 2.7, designed with motorsport in mind, not only featured a low front bumper, but also the characteristic spoiler protrusion above the tailgate, the legendary "duck rump".
- 1975 saw the premiere of the first 911 Turbo, featuring a large fixed rear spoiler with black polyurethane (PU) coating.
- In 1989, the first model with an electrically operated rear spoiler, the 911 Carrera 4 of the 964 series, debuted. This was the first step towards adaptive aerodynamics.
- In 2014, Porsche introduced the 911 Turbo with adaptive aerodynamics. Its front and rear spoilers were extended depending on the speed and the selected driving mode.