Chassis and assist systems
The GT philosophy behind the new 911 Speedster is also reflected in its chassis. With sporty rear-axle steering and dynamic engine mounts, the chassis is based on the technology of the 911 GT3 and 911 R. Control systems such as Porsche Torque Vectoring (PTV), Porsche Stability Management (PSM) and Porsche Active Suspension Management (PASM) with sports tuning and 25-millimetre lower body have been precisely adapted to the new requirements.
The open-top two-seater runs on 20-inch forged Speedster alloy wheels with road-approved sports tyres. As on racing cars, they have a central lock. The standard equipment also includes the high-performance PCCB brakes (Porsche Ceramic Composite Brake) with internally vented and perforated ceramic composite brake discs.
Together, these chassis components offer impressive performance with high mechanical grip, outstanding steering precision and minimum car body movements – the perfect conditions to guarantee unique driving pleasure on winding roads.
Rear-axle steering: agility and stability in perfection
The rear-axle steering fitted as standard adds additional agility and stability to the driving characteristics of the 911 Speedster. This three-stage system works with electromechanical actuators which allow steering angles of up to 1.5 degrees. At speeds up to around 50 km/h, the rear wheels steer in the opposite direction to the front axle. This virtually shortens the wheelbase and thus also the turning circle. At the same time, the Speedster responds more eagerly to steering commands. Between speeds of 50 and 80 km/h, the rear-axle steering responds depending on the situation. At speeds above 80 km/h, the rear wheels steer in the same direction as the front axle – the wheelbase is therefore virtually lengthened, thereby increasing driving stability, for example when changing lanes at high speeds.
Dynamic engine mounts: motor sports technology for series production
The dynamic engine mounts, a technology inspired by motor racing, make a significant contribution to the dynamics and handling of the 911 Speedster. The electronic control system combines the benefits of both hard and soft engine mounting, thus increasing both the driving comfort and stability. For a moderate driving style, the softer setting of the dynamic engine mounts helps to cushion the transmission of oscillations and vibrations from the drivetrain to the body, thus improving driving comfort. In contrast, hard engine mounting is particularly important for more sporty driving as it reduces the mass movement of the engine-transmission unit. For load changes and in fast bends, it ensures more precise, predictable and perceptibly more stable handling when the vehicle is being driven to its limits.
In addition, the dynamic mounts reduce the vertical engine oscillations at full acceleration. This enables more balanced and higher drive power at the rear axle, resulting in improved traction and faster acceleration.
Electronic control systems: high performance and safety
Porsche has precisely adapted the active chassis systems of the 911 Speedster to the special demands. The PASM variable damping control system with sport tuning allows the driver to choose between two driving modes. Normal mode is designed for sporty driving on public roads, and delivers high dynamics for changing road conditions and uneven surfaces. The Sport mode setup is designed to support maximum lateral acceleration and optimum traction on flat roads. The reduced car body movements significantly increase driving precision. Regardless of the mode selected, lowering the body by 25 millimetres lowers the centre of gravity of the 911 Speedster and emphasises the sporty appearance.
The Porsche Stability Management (PSM) of the 911 Speedster provides extremely sensitive and precise control. In the basic setup, PSM delivers a high degree of active driving safety and is supported for longitudinal dynamics by the subfunctions ASR (anti-slip regulation) and MSR (engine drag torque control) as well as ABS (anti-lock brake system) and ABD (automatic brake differential). Electronic Stability Control (ESC) is primarily used for lateral dynamics control. ESC is designed to counteract understeering or oversteering by performing wheel-selective brake interventions.
PSM can be optionally deactivated in two stages. ESC OFF mode deactivates the ESC lateral dynamics control and allows drifting by targeted steering and throttle movements. Traction control (TC) with ABD, ASR and MSR (engine drag torque control) remain activated. In the ESC+TC OFF mode, these control systems are also deactivated. This allows experienced drivers to enjoy unfiltered driving pleasure - for example on closed racing circuits.
Porsche Torque Vectoring Plus (PTV Plus) features a mechanical rear differential lock including asymmetrical locking action and targeted brake interventions on the rear wheels. This way, the system achieves high traction even on changing road surfaces, increases both the agility as well as driving stability for the 911 Speedster and supports steering precision.
Ceramic brakes: lighter, more powerful, greater durability and higher wear resistance
The 911 Speedster uses Porsche Ceramic Composite Brakes (PCCB) as standard. Compared to conventional grey cast iron components, their perforated ceramic composite brake discs are only around half the weight, significantly reducing the unsprung masses. They have a diameter of 410 millimetres on the front axle and 390 millimetres on the rear axle. The aluminium monobloc fixed calliper brakes painted in yellow have six pistons each at the front and four pistons each at the rear. Other benefits of PCCB: it combines higher brake performance with increased durability and resistance to wear.