brake sensor PORSCHE 911 2009 5.G Information Manual

Porsche Traction Management
(P TM).
Genuine high per formance calls
for more than just a power ful
engine. It also requires an ef fec-
tive means of delivering that
power to the road. One solution
to this is all -wheel drive. An
even bet ter one is the further-
enhanced Porsche Traction
Management (PTM), consisting

of active all -wheel drive with
electronically controlled multi -
plate clutch and including an
automatic brake differential (ABD)
and anti -slip regulation (ASR).
PTM improves vehicle dynamics
even further whilst ensuring that
none of the customar y traction
and driving safet y is lost. The
result is an even more enjoyable
sport y ride combined with
exceptional stability.
Torque is distributed actively
– and exceptionally quickly –
via an electronically controlled
multi-plate clutch. The advantage is that, through
continuous monitoring of the

driving conditions, a more imme -
diate response to changing
scenarios can be achieved. The
status is monitored with the aid
of on-board sensors. These are
used to measure a range of

values, including the rotational
speed of all four wheels, the
lateral and longitudinal accelera -
tion of the car, and the current
steering angle. The sensor data
is analysed in ‘real time’, enabling
immediate adjustments in front-
end drive torque as and when
required. If, for example, the rear
wheels lose traction under
acceleration, a greater proportion
of drive torque is automatically
transmit ted to the front axle. At
the same time, ASR prevents the
rear wheels from spinning by
adapting the engine power. When
cornering, the system controls
drive to the front wheels in order
to maintain optimum lateral grip.
On variable-grip surfaces, traction
is enhanced using the automatic
brake dif ferential (ABD). If a wheel threatens to spin, PTM brakes it
via ABD and in doing so transfers
more drive torque to the other
wheel on the same axle.
Assisting PTM is Porsche Stabilit y
Management (PSM). Combined,
these systems provide excellent
torque distribution – and there
-
fore outstanding performance –
in all driving conditions.
The benefits of PTM are most
evident in wet and snow y
conditions. In these conditions,
the 911 Turbo models of fer
breathtaking acceleration. In short, PTM provides greater
active safet y and greater

performance, combined with
exemplary balance.
Performance | Transmission
Active all -wheel drive
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Porsche Stability Management
(PSM).
PSM, an automatic vehicle sta-
bilit y control system designed to
aid the driver in critical road
scenarios, is fit ted as standard.
Sensors monitor the direction,
speed, yaw velocit y (speed of
rotation around the vertical axis)
and lateral acceleration of the car.
Using this information, it is
possible to calculate the actual
direction of travel at any given
moment. If the car begins to over -
steer or understeer, PSM applies
selective braking on individual
wheels to restore stabilit y and
optimum speed. Whenever PSM is
required to intervene, an indicator
light in the cockpit flashes.
When accelerating on wet or other
low-grip surfaces, PSM combines
with PTM and uses the automatic
brake differential (ABD) and anti-
slip regulation (ASR) functions to
maintain traction and stabilit y.
Included as standard equipment,
PSM assists with high -precision
inputs that enhance the agilit y of
each model. When ‘Sport ’ mode is selected on the Sport Chrono
Package Turbo with dynamic
engine mount system (page 58),
the PSM threshold is raised

higher still to enable greater
driver involvement – particularly
at speeds of up to 70 km/ h
(44 mph).
PSM includes ABS to help mini -
mise braking distances. System
inputs are smooth and precise
for greater driver comfort.
Active safet y is further enhanced
with the aid of t wo additional
brake functions: electronic brake
prefill and brake assist.
The prefill function is automati-
cally enabled whenever the

throt tle pedal is suddenly released.
The pressure in the brake lines
is marginally increased, bringing
each 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, by
contrast, is specifically designed
for use in emergency stops.
When the speed of brake pedal
application and the pressure on
the brake pedal exceed a prede -
fined threshold, the hydraulics
automatically apply the necessary
pressure to achieve maximum
deceleration. For a more actively involved

driving experience, PSM can be
manually disabled. PSM remains
present in the background and
will only intervene under heav y
braking where at least one front
wheel requires ABS assistance
(in ‘Sport ’ mode, if both front
wheels require assistance). The
automatic brake differential

(ABD) remains active at all times.
Vehicle yaw
Car steers of f line
Vehicle yaw
Car steers of f line PSM corrects
direction and
stabilises car
PSM corrects
direction and
stabilises carOversteer without PSM
Oversteer with PSM
Understeer with PSM
Understeer without PSM
Performance | Chassis
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