Safety and environment | Safet y · 66
65 · Safety and environment | Safet y
Outstanding brake performance.
To the point.
Braking systems.
Porsche brakes are renowned worldwide
as the benchmark in performance and
durability. Equipped with larger and more
powerful braking systems, the Cayenne
models continue this tradition by offering
excellent deceleration – even when the
car is fully laden with five adult occu -
pants, a full complement of luggage and
a braked trailer load of up to 3,500 kg
(Cayenne with manual gearbox: 2,700 kg).
All Cayenne models have internally
vented discs all round, ensuring con -
sistent performance during heav y use. The front disc dimensions (diameter/
thickness) are 350 mm/34 mm on
the Cayenne and Cayenne Diesel,
360 mm/36 mm on the Cayenne S,
Cayenne S Hybrid and Cayenne GTS, and
390 mm/38 mm on the Cayenne Turbo.
All models have
six-piston monobloc
aluminium brake calipers at the front
and four-piston equivalents at the rear.
The calipers are black on the Cayenne
and Cayenne Diesel and silver on the
Cayenne S and Cayenne S Hybrid. On
the Cayenne GTS and the Cayenne Turbo,
they feature a striking red paint finish.
Standard braking system on Cayenne Turbo Standard braking system on Cayenne S,
Cayenne S Hybrid/Cayenne GTS; calipers in red
Standard braking system on Cayenne, Cayenne Diesel
Braking is assisted by a tandem booster
and large brake master cylinder. Further
assistance is provided by PSM (p. 68).
For greater safet y, the brake pads are
equipped with wear sensors, alerting
the driver when new pads are required.
Electric parking brake.
Manually activated and deactivated,
the electric parking brake releases
automatically as you drive off.
Automatic hold function.
With the automatic hold function, you
can pull away on the flat or a slope
without ever rolling back. The system
automatically detects when the vehicle
has come to a halt on an uphill gradient.
PSM then maintains the brake pressure
at all four wheels for a brief period to
prevent the vehicle from moving in the
opposite direction.
Safety and environment | Safet y · 70
69 · Safety and environment | Safet y
Porsche Stability Management (PSM).
Porsche Stabilit y Management (PSM) is
an electronic control system that uses a
range of functions – including anti-lock
braking (ABS) – to help stabilise the
vehicle (and trailer, if fit ted) in hazardous
road scenarios. Throughout each journey,
sensors monitor the direction, speed,
yaw velocit y and lateral acceleration of
the car. Using this information, it is pos-
sible to calculate the actual direction of
travel at any given moment. If the car
begins to oversteer or understeer, PSM
applies selective braking on individual
wheels to restore stabilit y. If necessary,
PSM can also intervene in the engine
management system to temporarily
modify the amount of drive transmitted
to the wheels. PSM has three additional functions that
help reduce braking distances. If the
throt tle pedal is released suddenly, PSM
automatically readies the braking sys
-
tem. The pressure in the brake lines
is marginally increased, bringing each
of the pads into light contact with the
corresponding disc. If the driver goes on
to apply the brakes, the calipers respond
more quickly and the braking distance is
reduced.
In an emergency stop – i.e. when the
pressure on the brake pedal exceeds
a certain threshold – the brake assist
function uses the PSM hydraulics to
apply maximum braking force at all
four wheels.
Preparing for the road ahead.
With a little help from PSM.
For added safet y, the system also read -
ies the brakes whenever a decreasing
distance to the vehicle in front is detect -
ed. The optional adaptive cruise control
and PSM interact to prefill the brakes.
Even if adaptive cruise control is inactive,
the system registers the speed of the
vehicle in front and automatically readies
the braking system. In addition, the sys -
tem alerts the driver to the decreasing
distance by briefly tugging on the
brakes.
PSM also features a trailer stabilisation
function – for a significant contribution
to car and trailer safet y. Within the laws
of physics, it compensates for load
transfer caused by throt tle and brake inputs up to the maximum degree of
lateral acceleration. It also enhances the
car’s driving dynamics and directional
stability when accelerating on inconsis
-
tent road surfaces.
Other features include a special control
strategy in the ABS for braking on loose
surfaces. By briefly locking the wheels,
a wedge is formed ahead of each t yre
which provides additional purchase to
help slow the car, e.g. on gravel or snow.
For a more involving driving experience,
PSM can also be disabled, but remains
active in the background.
Standard on all Cayenne models.
