This latest evolution of Porsche
Stability Management (PSM)
provides automatic assistance in
critical road scenarios. A powerful
driver aid, it uses a range of
sensors to monitor the direction,
speed, yaw velocity (speed of
rotation around the vertical axis)
and lateral acceleration of the car.
With this information, it can
then calculate the actual direction
of travel. If the car begins to
oversteer or understeer, PSM
applies selective braking onindividual wheels to bring it safely
back into line. Whenever PSM is
required to intervene, an indicator
light in the cockpit is illuminated.
Another scenario in which PSM is
invaluable is when applying the
throttle on wet or other low-grip
surfaces. Here, PSM uses the ABD
(automatic brake differential) and
ASR (anti-slip regulation) functions
in PTM to maintain traction and
stability.Standard equipment on the
911 Turbo, PSM assists with high-
precision inputs that enhance the
athleticism and agility of the car.
When ‘Sport’ mode is selected
on the optional Sport Chrono
Package Turbo (see page 60),
the PSM threshold is raised
higher still enabling greater driver
involvement – particularly
at speeds of up to 70 km / h
(44 mph).
The integral ABS ensures shorter
braking distances in critical road
scenarios. System inputs are
smooth and precise fo r greater
driver comfort. Active safety is
further enhanced with the aid of
two additional brake functions:
electronic brake prefill and brake
assist.
The prefill function is automatically
enabled whenever the throttle
pedal is suddenly released. The
pressure in the brake lines is
marginally increased, bringingeach of the pads into light contact
with the corresponding disc. If
the driver then decides to use the
brakes, the system can apply
the maximum force with virtually
no delay.
The brake assist function is
specifically designed for use in
emergency stops. When the
pressure on the brake pedal
exceeds a predefined threshold,the brake assist function uses
the PSM hydraulics to apply the
pressure required for maximum
deceleration. The result: shorter
braking distances.
For a more natural drive, PSM can
be manually disabled leaving only
the automatic brake differential
(ABD) in place. Although essentially
inactive, PSM remains present in
the background and can intervene
immediately under heavy braking
where at least one front wheel
requires ABS assistance. In ‘Sport’
mode, PSM will only respond
when ABS is active on both front
wheels.
In short, PSM provides the ideal
balance between electronically
assisted active safety and
freedom to enjoy the car’s
potential.
· 58 ·· 59 ·
Oversteer without PSM Oversteer with PSM
Car steers off line
Car steers off line PSM corrects
steering and
stabilises car
PSM corrects
steering and
stabilises car
Understeer without PSM Understeer with PSM
The new 911 Turbo |Chassis
Porsche Stability Management (PSM).
Enhanced stability control for the new 911 Turbo.
The new 911 Turbo is also
available with an optional high-
performance braking system:
the Porsche Ceramic Composite
Brake (PCCB). Successfully
tested in the toughest endurance
racing, this unique technology
has been further refined for even
greater road performance.The key components in PCCB
are the moulded ceramic discs
(front/rear diameter: 380 mm/
350 mm). The larger front discs
provide greater leverage and
therefore better brake performance.
Thediscsaremadefrom a
specially treated carbon-fibre
compound that is silicated in a
high-vacuum process at 1,700 ºC.
The resulting material is not
only much harder than metal, it
is also more resistant to heat.
Even at high temperatures, the
thermal resistance of the PCCB
disc ensures excellent dimensional
stability. The ceramic material is
totally resistant to corrosion and
offers excellent acoustic damping
properties.The pads are mounted in six-
piston monobloc aluminium
fixed calipers at the front, with
four-piston units at the rear.
The resulting brake forces are
not only extremely high, they are
also exceptionally consistent.
The pedal response is fast andprecise, with only moderate input
required.
The key advantage of PCCB is the
total weight saving over comparable
metal discs of approximately 50 %.
As well as enhancing performance
and fuel economy, this represents
a major reduction in both the
unsprung and rotating masses.
This, of course, produces
additional benefits in terms of
comfort and road-holding on
uneven road surfaces as well as
general handling and agility.
For more information, see thelatest PCCB brochure available
from your Porsche Centre.
· 70 ·· 71 ·The new 911 Turbo |
Safety
PCCB
Porsche Ceramic Composite Brake (PCCB).
When it comes to developing new brake technology,
nothing holds us back.
