
Driving and Driving Safety 181
Porsche Stability Management
(PSM)
PSM is an active control system for stabilization of the vehicle during extreme driving maneuvers.
PSM makes use of both the automatic brake differential (ABD) and anti-slip regulation (ASR) systems, as well as the functions of the anti-lock brake system (ABS) and engine drag torque control system (MSR).
In spite of the advantages of PSM, it is still the driver’s responsibility to adapt his driving style and maneuvers in line with road and weather conditions, as well as the traffic situation.
The increased safety that is provided should not induce you to take greater risks with your safety. The limits set by the physics of driving cannot be overcome, even with PSM.Risk of accidents due to inappropriate speed cannot be reduced by PSM.
Advantages of PSM
– Best possible traction and lane-holding ability in all driving situations – even on road surfaces with varying friction.– The system compensates for undesired vehicle reactions (Ferraria effect) when the driver releases the accelerator pedal or brakes on bends. This compensation functions up to the maximum lateral acceleration.– PSM actively helps to stabilize the vehicle if necessary during dynamic driving maneuvers (e.g. rapid steering movements, during lane changes, or on alternating bends).
– Improved braking stability on bends and on different or varying road surfaces.– Improved brake function and shorter stopping distance in the event of emergency braking.
Readiness for operation
PSM is switched on automatically every time you start the engine.
Function
Sensors at the wheels, brakes, steering system and engine continuously measure:– Speed– Direction of travel (steering angle)– Lateral acceleration– Axial acceleration– Rate of turn about the vertical axis
PSM uses these values to determine the direction of travel desired by the driver.PSM intervenes and corrects the course if the actual direction of motion deviates from the desired course (steering-wheel position):It brakes individual wheels as required. If necessary, PSM also influences the engine power or the gear-changing characteristic of Porsche Doppelkupplung (PDK) in order to stabilize the vehicle.
The events below inform the driver of PSM control operations and warn him to adapt his driving style to the road conditions:– PSM warning light on the instrument panel flashes.– Hydraulic noises can be heard.– The vehicle decelerates and steering-wheel forces are altered as PSM controls the brakes.– Reduced engine power.– The brake pedal pulsates and its position is changed during braking.In order to achieve full vehicle deceleration, foot pressure must be increased after the brake pedal has begun vibrating.
Examples of PSM control operations
– If the “front wheels of the vehicle drift” on a bend, the engine power is reduced and the rear wheel on the inside of the bend is braked if necessary.– If the rear of the vehicle swings out on a bend, the front wheel on the outside of the bend is braked.– Brake system prefilling:The brake system is prepared for possible subsequent emergency braking if the accelerator pedal is released suddenly and quickly. The brake system is prefilled and the brake pads are already applied gently to the brake disks.– Brake booster (Hydraulic Brake Assist):In the event of an emergency braking operation where the pedal force is insufficient, a brake booster provides the braking pressure necessary for maximum deceleration at all 4 wheels.
Loss of control over the vehicleWARNINGh
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182 Driving and Driving Safety
Combined operation of PSM and PTV Plus
In order to ensure optimum stabilization of the vehicle, the center differential lock is influenced when PSM interventions occur on vehicles with PTV Plus.
Combined operation of PSM and PTM
In order to ensure optimum stabilization of the vehicle, torque distribution between the front and rear wheels is adapted and the differential lock is influenced when PSM interventions occur on vehicles with PTV Plus.
In the event of a PTM fault, PSM cannot be switched off.If PSM is switched off, it is switched on again automatically.
Automatic brake differential (ABD)
The ABD system controls the front and rear axles separately. If one wheel of an axle starts to spin, it is braked so that the other wheel on the same axle can be driven.
ABD recognizes different driving states, and it features control strategies adapted to these states. In situations in which little propulsive power is required, such as when the vehicle moves off on a level gravel surface, traction control already becomes active at low engine speeds. If a large amount of propulsive power is required, e.g. when driving off on an uphill slope or for rapid acceleration, the ABD system is adapted accordingly.
Anti-slip control (ASR)
The anti-slip control system prevents the wheels from spinning by adjusting the engine power, thereby ensuring good lane-holding ability and stable handling.
Engine drag torque control (MSR)
In conditions of excessive slip, the engine drag torque control system prevents all driven wheels from locking up when the vehicle is overrunning. This is also the case for downshifts on a slippery road.
Steering torque pulse
The steering torque pulse provides the driver with steering assistance when braking on road surfaces with differing friction values.Additional steering forces also assist the driver during counter steering.
Switching off PSM
fPress button for at least 1 second.PSM is switched off after a short delay.The indicator light on the button and the PSM OFF warning light on the instrument panel light up.The warning “ PSM off” appears on the multi-function display in the instrument panel.
When you brake in the ABS control range , the vehicle is stabilized even when PSM is switched off.
One-sided spinning of the wheels is prevented, even with PSM switched off.
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186 Driving and Driving Safety
Selecting the PASM mode
1.Switch on ignition. 2. Press button (repeatedly).
On the button: – No indicator light comes on when “ Chassis Normal selected ” is selected (default setting).– An indicator light comes on when “ Chassis Sport selected ” is selected.
In addition, the selected chassis setup is shown on the multi-function display in the instrument panel for approx. 4 seconds.
Information
The last selected chassis setup is stored in the memory after the ignition is switched off.
Warning message
The system automatically detects PASM faults and displays them on the multi-function display in the instrument panel.
For information on warning messages on the multi-function display:fPlease see the chapter “OVERVIEW OF WARNING AND INFORMATION MESSAGES” on page 129.fAdapt your driving style according to the changed conditions.fContact an authorized Porsche dealer in order to correct the fault.
Porsche Torque Vectoring
(PTV Plus)
Functional Description
Despite the advantages of PTV, it is still the driver’s responsibility to adapt his/her driving style and maneuvers in line with road and weather conditions, as well as the traffic situation.
The increased safety that is provided should not induce you to take greater risks with your safety. The limits set by the physics of driving cannot be overcome, even with PTV.Risk of accidents due to inappropriate speed cannot be reduced by PTV.
PTV Plus consists of a control system that performs braking interventions based on driving dynamics to achieve variable drive torque distribution on the rear axle and of an electronically controlled rear differential lock.
PTV Plus improves steering response and precision through gentle braking interventions on the inside rear wheel. This braking action cannot be felt by the driver. The vehicle follows the steering angle of the front wheels more precisely. Understeer is largely prevented in the limit range. This increases the lateral acceleration potential and higher cornering speeds are possible.
The electronically controlled rear differential lock continuously monitors the driving condition of the vehicle and distributes the drive torque to the rear axle as required.
Loss of control over the vehicleWARNINGh
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188 Driving and Driving Safety
Dynamic Engine Mounting (PADM)
On vehicles with Sport Chrono package
Dynamic Engine Mounting with variable damping is a system designed to enhance both driving dynamics and driving comfort. Depending on the driving situation, the ideal mounting rigidity and damping is automatically set in the range between an rigid engine-to-body connection (increase in driving dynamics) and decoupling of the engine from the body (increase in driving comfort).
“Sport” mode
When “ Sport” mode is switched on, a more rigid engine-to-body connection is achieved for a sporty driving style.
“Sport Plus” mode
When “ Sport Plus” mode is switched on, an optimal engine-to-body connection is achieved for driving on race circuits.
Warning message
Dynamic engine mounting faults are indicated by a warning message on the multi-function display.fPlease see the chapter “OVERVIEW OF WARNING AND INFORMATION MESSAGES” on page 129.
“Sport” and “Sport Plus” mode
The selectable chassis settings mean that the vehicle can offer various modes for a sportier overall setup.The “ Sport” mode pushes the control systems more in the direction of greater emotionality and performance during every day driving.
In “ Sport Plus” mode, maximum performance is set for race-circuit-like driving:– In “ Sport Plus” mode: PASM (Porsche Active Suspension Management) is automatically changed to “ Chassis Normal” or “Chassis Sport” mode. – In “ Sport Plus” mode: Like PASM, PDCC is switched to the corresponding “ Sport” mode, whereby the rolling movements of the vehicle are reduced further, depending on the selected mode.– The PDK transmission switches to a sporty gear-changing map and shortens the gear shifting times when Sport mode is activated. Gear changes take place faster.– The electronic accelerator pedal reacts sooner, and the engine is more responsive to throttle inputs. When Sport mode is switched on and the vehicle is traveling at a speed of less than 40 km/h (25 mph), this function is activated only after the driver has floored the accelerator pedal or released it briefly.– The rpm limiter characteristic is “harder”. In other words: the engine is immediately throttled when the performance limits are reached (only in manual selection mode on vehicles with PDK).
– PSM (Porsche Stability Management) control is more sporty in “ Sport Plus” mode. PSM interventions are later than in Normal mode. The driver can maneuver the vehicle with greater agility at its performance limits, without having to dispense with the assistance of PSM in emergency situations. This helps to achieve optimal lap times, particularly on race circuits with a dry road surface.– PADM changes to more sporty maps for the dynamic engine mountings to achieve a stiffer engine-to-body connection.In “ Sport” for a sporty driving style, in “ Sport Plus” mode for race-circuit-like driving. – PTV Plus changes to a more dynamic map when “ Sport Plus” is switched on. – The dynamic cornering light reacts more spontaneously to steering angle changes.– The sports exhaust system is be switched to a sound-optimized mode, but can be switched off separately via the button.The Auto Start Stop function and coasting mode are deactivated.fPlease read the relevant chapters.
Overboost function
On vehicles with Sport Chrono package
When “ Sport” or “Sport Plus” mode is switched on and the accelerator is fully pressed, the boost pressure is temporarily increased by approx. 2 psi (0.15 bar) in the medium engine-speed range and the maximum torque increases.
For information on the torque display:fPlease see the chapter “PERFORMANCE MENU” on page 116.
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200 Storage, Luggage Compartment and Roof Transport System
Roof Transport System
A roof transport system can be fitted on the vehicle for transporting various sports and hobby equipment.
Various objects can be transported safely and securely using the roof transport system and additional attachments, e.g. ski rack, bicycle rack, surfboard rack, roof box or snowboard holder.fOnly use roof transport systems that have been tested and approved by Porsche. It is not possible to fit commercially available roof rack systems.
fInstall individual load-carrying devices, such as ski rack or roof box as centrally as possible with respect to the supports.fDo not exceed the permissible roof load, permissible gross weight and permissible axle loads.Details of these weights and loads can be found under “Technical data” in this Owner’s Manual:Please see the chapter “WEIGHTS” on page 288.fDistribute load evenly, with heavy items as low as possible. Items of luggage must not project beyond the side of the load area.fFix and secure every item to the basic carrier with a rope or lashing strap (do not use elastic rubber tensioners).fBefore every trip, and at regular intervals during long trips, check that the Roof Transport System and load are secure. Re-tighten if necessary and secure further by locking. Tighten all fastening screws again.
When the Roof Transport System is loaded, the maximum speeds depends on the nature, size and weight of the load being carried.fDriving, braking and steering behavior change due to the higher center of gravity and the greater wind resistance. You should adapt your driving style accordingly.Nevertheless, Porsche recommends that you do not exceed the posted speed limit.fNever drive faster than 80 mph (130 km/h) when the Roof Transport System is fitted and loaded.fWith the basic carrier fitted and no load, do not exceed a maximum speed of 110 mph (180 km/h).
Washing the vehicle in a car wash or failure to observe the overall vehicle height or the maximum permitted gross weight can damage the vehicle or roof transport system.fRemove the complete roof transport system before washing the vehicle in a car wash.fCheck the overall vehicle height with the roof transport system fitted before driving into multi-storey car parks, garages, underground garages and tunnels.fDo not exceed the permissible roof load, permissible gross weight and permissible axle loads.Details of these weights and loads can be found under “Technical data” in this Owner’s Manual:Please see the chapter “WEIGHTS” on page 288.
A - Front carrier (long) B - Rear carrier (short) C - Cover trims D - Torque wrench E - Key
Fitting the roof transport system
When fitting the roof transport system for the first time, the front and rear carrier must be adjusted according to the width of the vehicle.
Roof Load InstabilityWARNINGh
NOTICE
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Storage, Luggage Compartment and Roof Transport System 201
1.Lift seals F on the roof rail using the hook of the torque wrench and pull them out. 2. Fold out all eight rotary holders G using the hook of the torque wrench. 3. Unlock cover flaps H using the key and fold upwards as far as possible.4. Ensure that the carriers are fitted in accordance with the stickers on the underside of the carriers.
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202 Storage, Luggage Compartment and Roof Transport System
5. When fitting for the first time: Remove the handle from the torque wrench.Loosen screws on the underside of the carriers using the short side of the torque wrench.
Information
It is only necessary to loosen the screws on one underside section of the relevant carrier.
Place long carrier A at the front and short carrier B at the rear on the rotary holders G and, at the same time, adapt to the vehicle width by means of the moveable carrier supports.Tighten the screws on the underside sections of the carriers slightly.
Remove the carriers and retighten the screws on the underside sections of the carriers using the short side of the torque wrench.6. Refit the handle of the torque wrench.
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Storage, Luggage Compartment and Roof Transport System 203
7.Place the carriers on rotary holders G.
Risk of damage to the seals through unintentional pinching between roof and supports.fInsert seals F in the supports.
8. First, screw in all eight carrier fastening screws using torque wrench D until flush with the surface. Then tighten all eight screws until the arrow markings on the torque wrench are exactly aligned.
9. Fold the cover flaps H of the carriers fully downwards and push the desired load-carrying device (e.g. ski box, bicycle carrier) into the carrier.
10. Cut the cover trims C to size and push them sideways into the carriers or press them into the carriers from above to protect against moisture and dirt as well as to prevent wind noise.11. Fold up and lock the cover flaps.
Information
fAfter driving 30 miles (50 km), retighten all screws on the carriers and load-carrying devices.
NOTICE
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