The chassis of the new 911 GT3 makes comprehensive use of thoroughbred motorsport technology like no other production model from Porsche before. This applies in particular to the front wheel suspensions. Their completely newly developed double-wishbone design is taken from formula racing cars. It was used by Porsche in 2005 on the legendary RS Spyder LMP2 prototype and was then also adopted for the 911 RSR Le Mans class winner in 2017. It is now used on a Porsche road-going vehicle for the first time and lends the 911 GT3 exemplary turn-in agility in combination with higher cornering performance and greater braking stability. In short, it makes the GT sports car faster and more predictable, and at the same time improves its driveability.
The new double wishbone front axle offers numerous advantages compared with the conventional McPherson spring strut layout. It offers higher camber stiffness under high compression and provides more constant support specifically for the wheel on the outside of a bend. This makes it possible to call on higher cornering force potential over the entire spring travel. At the same time, the double wishbone design inherently counteracts brake diving due to the different angles of the longitudinal polar axes. The spring struts are installed angled towards the rear and serve the same purpose. The wheel can therefore also evade any acting forces towards the rear instead of only in an upward direction.
In addition, the double wishbone front axle eliminates the disturbance from lateral forces on the shock absorbers when cornering. These can lead to distortion in the form of bending loads and cause higher frictional losses. With a twinkle in his eye, Andreas Preuninger, overall project director for GT road cars, explains this as follows: “Let us assume you are doing knee bend exercises and someone pushes you from the side – with a McPherson suspension you would lose your balance. A double wishbone axle stabilises you in the shoulder area, and you can continue the exercise undisturbed …”
Multi-link rear axle with additional ball joints
To ensure that the chassis is well-balanced, the proven LSA (lightweight, stable, agile) five-link rear axle is equipped with additional ball joints for the lower wishbones, which are subject to particularly high stress. Used instead of elastokinematic rubber components, they now ensure practically play-free and therefore especially precise connection to the body on the inner and outer sides. As a result, they also create a particularly direct connection to the road. Like on the front axle, the camber and anti-roll bar stiffness can be adjusted individually in order to find the ideal set-up for every circuit. As on the front axle, the stiffer springs are supported by helper springs. Like on Porsche racing cars, these extend the spring travel and make sure that the vehicle does not lose contact with the ground on crests, for example, in spite of the high spring rates. Special shock absorbers round off the comprehensively upgraded running gear. These permit a larger bandwidth between the soft and hard characteristics as well as faster and more precise response of their valve system. They therefore successfully manage the balancing act between greater comfort in everyday driving on the one hand and better race track performance on the other.
Rear-axle steering increases agility and stability
The rear-axle steering also makes a significant contribution to the tremendous driving dynamics of the 911 GT3. Up to a speed of approximately 50 km/h, it turns the rear wheels by a maximum of 2.0 degrees in the opposite direction to that of the front wheels. This virtual shortening of the wheelbase by 6 mm reduces the turning circle and makes parking manoeuvres easier, for example. At the same time, it also ensures more direct turn-in behaviour when steering into bends. In contrast, at speeds above 80 km/h the rear wheels steer in the same direction as the fronts by up to 2.0 degrees. The result? The virtual lengthening of the wheelbase by 6 mm increases cornering stability. Between speeds of 50 and 80 km/h, the rear-axle steering responds depending on the situation.
Like on its predecessor, Porsche is offering an optional front axle lift system on the new 911 GT3. At speeds between 35 and 60 km/h (depending on country), it increases the ground clearance at the front spoiler lip by 46 mm, and therefore allows the car to drive over speed bumps without bottoming out, for example. The intelligent Smart Lift memory function is new: it stores the position of an obstacle and then automatically lifts the car at this location in the future.
Active chassis systems underline high-performance character
Porsche Stability Management (PSM) offers a protecting hand for the new 911 GT3. Its special, particularly sporty set-up matches the dynamic character of the high-performance sports car and allows greater freedoms before it intervenes to provide assistance. As a general rule, Porsche sets up the chassis on its models so that they already combine the best possible performance with safe handling without the use of electronic control systems. Like on all GT vehicles from Porsche, the PSM of the new 911 GT3 can be switched off either fully or with the exception of the traction control (TC) system. This allows its full potential to be exploited, for example when driving on the race track.
The variable damping control system Porsche Active Suspension Management (PASM) offers advantages both on closed circuits and in daily driving. Its special GT3 configuration is combined with a 20 mm-lower ride height compared with the 911 Carrera. Two control maps can be selected: Sport offers sufficient suspension comfort for long-distance driving, while Track reduces body movements to a sportily firm level.
Larger brakes for even better deceleration
The more powerful brake system of the new 911 GT3 is able to reliably cope with the improved performance. Internally vented grey cast-iron brake discs are used as standard, and these are now dimpled instead of cross-drilled. In other words, the holes, which primarily serve to remove brake dust, are provided with cone-shaped openings. The result is higher material strength and more powerful braking action. The front discs are also much larger than on the previous model and have a diameter of 408 mm instead of 380 mm.
Two special air paths optimise brake cooling on the front axle: the upper path is responsible for internal cooling of the brakes, while the lower path makes use of the underbody air flow and cools the friction ring. The latter is clamped by especially rigid aluminium monobloc fixed callipers with six pistons. These respond quickly and offer a precise pressure point even under high loads. The brake discs of the rear wheels have an unchanged diameter of 380 mm and monobloc brake callipers with four pistons. Like at the front, the callipers are painted red in each case, but are also available in high-gloss black. The brake pads of the new 911 GT3 do without the use of copper for the first time.
Optionally available: Porsche Ceramic Composite Brake (PCCB)
The Porsche Ceramic Composite Brake (PCCB) system is available as an option on the new 911 GT3. If not otherwise requested, this is characterised by yellow-painted brake callipers. The ceramic composite material used here impresses thanks to its high thermal load capability and significant weight advantages: the PCCB brake discs – with a diameter of 410 mm at the front and 390 mm on the rear axle – weigh a good 50 per cent less than comparable grey cast-iron components. As a result, they reduce the unsprung and rotating masses even further, which in turn greatly benefits driving dynamics.
Lightweight forged wheels with double mixed tyres
Porsche has also taken a new approach in terms of the wheels and tyres for the 911 GT3: the front and rear axles are equipped with different wheel sizes for the first time – this was previously a typical characteristic of RS models: 20-inch wheels are used at the front and 21-inch wheels at the rear. The rim width at the front has been increased from 9.0 to 9.5 inches. Nevertheless, the finely designed but extremely robust forged alloy wheels weigh 0.8 kg less in total than the wheels on the predecessor model. Among other things, this is achieved through the use of a centre-lock wheel nut, which has been adopted from motorsport. The 911 GT3 wheel has a silver painted finish as standard. Alternatively, it is also available in satin-gloss Dark Silver, Neodyme and Black. The latter option can also be upgraded with a painted rim edge in Shark Blue or Guards Red.
High-performance sports tyres – or race track tyres as an option for first time
The tyres naturally have a great influence on the performance of the new 911 GT3. As standard equipment, Porsche provides the powerful GT car with high-performance sports tyres. Ths measure 255/35 ZR 20 at the front, and 315/30 ZR 21 at the rear, ensuring superior grip. All four tyres are 10 mm wider than before. The larger contact area benefits cornering speeds, traction and braking. Race track tyres with approval for road use are a new option. Following on from the 911 GT3 RS, Porsche now offers these tyres for the 911 GT3 through its dealer network. Their performance focus is specifically on dry road conditions in terms of tread compound and tread design.
