PORSCHE 911 TURBO 2004 4.G Information Manual

· 50 ·· 51 ·The new 911 Turbo |
Chassis
Designed to reach the heights of performance.
With all four wheels on the ground.
Chassis

The rear axle assembly is a race-
proven design featuring multi-link
LSA (Lightweight, Stable, Agile)
subframe-based suspension. Its
lightened construction provides
exceptional dynamic properties.
The axle kinematics improve
stability under acceleration by
reducing excessive compression.
The lightweight strut has an
aluminium damper instead of
conventional steel to help improve
handling and agility.
Combined, the suspension enables
smooth high-speed manoeuvres
in all road and track scenarios.
Pitch and roll are reduced to a
· 53 ·The new 911 Turbo |
Chassis
To transmit power with optimum
efficiency, the front and rear
suspension must be a s stable,
and as light, as possible.
Reducing weight, particularly on
the unsprung masses, brings
major benefits in terms of driving
dynamics.The new 911 Turbo is equipped
with an electronic damping
system as standard. For more
information on Porsche Active
Suspension Management (PASM),
see page 56.The independent front suspension
combines McPherson-type struts
with longitudinal and transverse
links. Each front wheel is preciselylocated, ensuring excellent
handling and directiona l stability.
Brake spoiler elements provide
efficient cooling for each of the
front brake units.
· 52 ·Front axle 911 TurboRear axle 911 Turbo
Suspension.
Precision, strength and lightweight design.
minimum, as are tyre noise and
vibration. Overall, the car offers
a level of stability that is equal to
the car’s performance potential.

The power-assisted steering is
not only sensitive and direct,
it also offers accurate feedback
from the road. Minimal driver
effort is required when parking,
while the turning circle is small
at just 10.9 metres – despite
the generous tyre width.
One of the key features of
the new steering system is thevariable-ratio gearing. Around the
straight-ahead position, the ratio
is less direct, enabling smoother
manoeuvres on the motorway. It
also reduces the risk of excessive
steering inputs which could
destabilise the car at high speed.
Turn the wheel harder and
the ratio becomes more direct,
enabling better manageability
through low-speed corners as well
as easier parking manoeuvres.
In all scenarios, the system
provides excellent feedback
while complementing the car’s
natural agility.
In short: all the precision of a
race-proven system, yet perfect
for everyday road use.
· 54 ·· 55 ·The new 911 Turbo |
Chassis
Wheels.
The final elements in the drivetrain
system are, of course, the
wheels and tyres. On the new
911 Turbo, we’ve used 19-inch
forged alloys as standard. The
front wheel dimensions are
8.5J x 19 with
235/35 ZR 19
tyres. Rear wheel size is 11J x 19
with 305/30 ZR 19 tyres. The
new wheel design features a
special two-tone look for even
greater visual impact. The sides
of each spoke have a titanium
paint finish, while the entire front
surface, including the flange, has
a polished finish.
Tyre Pressure Monitoring (TPM),
included as standard equipment,
provides early warning of
tyre pressure loss. The driver is
i
nformed via the on-board
computer display as well as a
separate indicator light.A range of optional 18 and 19-inch
winter wheels (all snow chain-
compatible) are available from
Porsche Tequipment. Vehicles
equipped with the optional
Porsche Ceramic Composite
Brake (PCCB) may only be fitted
with 19-inch winter wheels.
19-inch Turbo wheel
Steering.
Accuracy, comfort and excellent road contact.

The new 911 Turbo is equipped
with Porsche Active Suspension
Management (PASM) as standard.
This electronic active damping
system offers continuous adjust-
ment of the damping force on
each wheel based on current road
conditions and driving style.
PASM has two driver-selectable
setup modes, ‘Normal’ and ‘Sport’,
which share a minimal degree
of overlap. While ‘Normal’ provides
a blend of performance and
comfort, the ‘Sport’ setup mode
has a much firmer range of
settings. The system responds to
changing road conditions and/or
driving style by continuously
varying the individual damping
forces within the parameters
defined for the selected setup
mode (‘Normal’ or ‘Sport’).
PASM uses a range of sensors
to monitor any movement in the
body of the car (e.g., under
acceleration, braking or on uneven
road surfaces). The PASM control
unit uses this data to obtain a
real-time evaluation of the forces
acting on the car. The system
responds continuously with a
corresponding modification of
individual damping force s in
accordance with the selected
setup mode. The results are a
reduction in both pitch and roll
as well as consistent road-holding
from all four wheels.
If ‘Sport’ mode is selected, the
suspension is set to a harder
damper rating. If the quality of
the road surface falls below a
certain threshold, the system
immediately changes to a softer
rating within the ‘Sport’ setup
range. This adjustment enhances
occupant comfort as well as
traction and grip. When the road
surface improves, PASM
automatically reverts to the
original, harder rating.
If ‘Normal’ mode is selected, and
the car is driven more assertively,
PASM automatically switches to
a harder rating within the ‘Normal’
setup range. As the dampers
become stiffer, the car becomes
more stable, ensuring higher
levels of active safety as well as
greater enjoyment from your
Porsche.
Limited-slip differential.
The manual gearbox version of
the new 911 Turbo is available with
an optional mechanical limited-slip
rear differential. Key benefits
include greater rear-end traction
when exiting hairpin bends as
well as on variable-grip surfaces.
It also compensates for changes
in wheel loads caused by throttle
modulation when cornering.
· 56 ·· 57 ·The new 911 Turbo |
Chassis
Porsche Active Suspension Management (PASM).
From ultimate comfort to optimum performance,
all at the push of a button.
Rebound in ‘Normal’ mode –
damper piston with bypass
valve openRebound in ‘Sport’ mode –
damper piston with bypass
valve closed
Compression in ‘Sport’ mode –
damper piston with bypass
valve closedCompression in ‘Normal’ mode –
damper piston with bypass
valve open

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 a prime
example of the ongoing evolution
of Porsche engineering. For
another step up in all-round
performance, there’s the optional
Sport Chrono Package Turbo.
This integrated system provides
simultaneous enhancement
for engine, chassis and optional
Tiptronic S transmission.
Key features include a digital and
analogue timer located centrally
on the dashboard, a ‘Sport’ select
button on the centre console,
a performance display in the
standard Porsche Communication
Management (PCM), a personal
memory function in PCM, and
a special ‘overboost’ function
unique to the new 911 Turbo.When ‘Sport’ mode is selected,
the engine management system
applies a new set of variables
creating a much more aggressive
response. A modified throttle
map relates the pedal position in
the footwell to a wider angle
of opening on the throttle. As a
result, the engine has a much
more positive reaction to every
pedal input. In the higher gears,
a hard rev-limiter helps protect
the engine under power.
Under full acceleration, the
‘overboost’ function provides a
temporary increase in available
boost pressure of approximately
0.2 bar. The overboost is applied
across the medium rev range,
raising the standard 620 Nm of
torque to as much as 680 Nm.
The modified throttle is matched
by PASM, which also switches
to ‘Sport’ mode. The dampers
become firmer, enabling fasterturn-in as well as better contact
with the road.
On vehicles with Tiptronic S,
the basic gearshift pattern is
automatically switched to high-
performance mode. The gearshift
action is virtually instantaneous,
while the shift points are timed for
maximum acceleration. Lift off
the throttle – even at high revs –
and the system automatically
shifts down to apply engine
braking. There are no unwanted
upshifts in manual mode when
approaching the engine rev limit.
Since the driver has control over
every upshift, the handling of
the car is smooth and assured,
particularly when braking for a
corner.
To minimise assistance from
PSM, the trigger threshold for
this system is raised. The result
is a more natural and involving
response to both lateral andlongitudinal forces. Mid-corner
agility is considerably enhanced,
with greater scope for oversteer
on turn-in and exit. This added
freedom is particularly apparent
in lower-speed sequences and
bends. For even greater driving
pleasure, the all-wheel drive
system applies a greater
proportion of drive torque to the
rear.
· 60 ·· 61 ·The new 911 Turbo |
Chassis
‘Sport’ button on centre console
Sport Chrono Package Turbo.
Additional power, precision timing.

For maximum manoeuvrability,
PSM can be partially disabled
while the car is still in ‘Sport’
mode. PSM simply monitors the
forces acting on the car and
will only intervene in the most
critical of situations, e.g., when
ABS assistance is required on
both front wheels.
To help you quantify this
increased performance, the
Sport Chrono Package Turbo
includes a swivel-mounted timer
on the dashboard. Functions
are accessed via the control
stalk for the on-board computer.
Analogue dials measure hours,
minutes and seconds, while aseparate digital field displays
whole seconds, tenths and one
hundredths of a second. The
digital field runs in parallel with
a second display which is
conveniently located in the
instrument cluster.
Individual lap times can be
viewed, stored and analysed using
a special ‘performance display’
added to Porsche Communication
Management (see page 86).
Available information includes the
time and distance travelled on
the current lap, as well as the
number of laps completed and
the respective times. The system
can also display the current
fastest lap and remaining range
till empty. Driving times can be
recorded for any stretch of road
and benchmark times can be
defined. Other useful features
include a memory function
accessible via PCM. This can beused to store a range of personal
preferences, such as daytime
driving lights, ‘Welcome Home’
light function, air conditioning,
rain sensor activation and door-
lock mode.
· 62 ·· 63 ·The new 911 Turbo |
Chassis

· 64 ·· 65 ·The new 911 Turbo |
Safety
What is the secret of
uncompromising performance?
Always put safety first.
Safety

The horizontal indicators in the
outer front air intakes feature high-
performance light-emitting diodes
(LEDs) for optimum visibility.
The standard front foglights on
the front apron moulding are
another distinctive design feature
on the new 911 Turbo.
At the rear of the car, the High-
Level third brake light is also
equipped with fast-response LEDs.
A pair of additional lights on the
inside of each door offer greater
convenience and safety at night.
The kerb light (white) provides
greater visibility when exiting the
car. The safety light (red) warns
traffic approaching from the rear
that the door is currently open.
The standard lighting system on
the new 911 Turbo features the
latest Bi-Xenon gas-discharge
technology offering a light quality
similar to daylight. The compact
main headlights provide a broad
swathe of light, ensuring greater
active safety in all road scenarios.Each headlight unit contains a gas-
discharge lamp featuring dynamic
range control. This automatic
adjustment of the light-beam angle
prevents hazardous dazzling of
oncoming vehicles due to small
undulations in the surface of the
road or heavy rear-end loads.The brightness of the lights is
approximately twice as great as
that of a halogen lamp. Other
standard features integral to the
system include a headlight cleaning
function.
· 66 ·· 67 ·The new 911 Turbo |
Safety
High-Level third brake lightBi-Xenon headlight
Active safety: lighting system.
Bright ideas for the darkest night.

Power, torque, acceleration,
and flexibility: in every respect,
thenew911Turboismore
accomplished than ever before.
The logical adjunct to all these
improvements is a corresponding
increase in brake performance.
To achieve that capability, the
standard braking system combines
six-piston fixed calipers at the
front of the car with newly devised
four-piston units at the rear.The red-painted calipers have a
monobloc (one-piece) aluminium
construction offering greater
stability, better ‘bite’ character-
istics under heavy braking, and
a further reduction in unsprung
weight. The brakes are quick
to apply and release, while the
pedal travel is short and the
bite point precise and consistent.
The front and rear discs have a
generous diameter of 350 mm.
All four discs are cross-drilled for
better performance in the wet.
The distinctive drill-hole pattern
enables a faster response by
allowing rapid dispersa l of the
water vapour generated under
braking. The discs are also
internally vented for better heat
dispersal. The result: excellent
stability in all conditions.
Other features include four-
channel ABS offering a smoother,
low-pulse action. Brake spoiler
elements provide effectivecooling for all key brake
components. A powerful tandem
brake booster unit enables easier
pedal inputs.Braking distances are further
reduced with the aid of two new
functions in the latest evolution
of the standard Porsche StabilityManagement (PSM): electronic
brake prefill and brake assist
(see page 58).
· 68 ·· 69 ·The new 911 Turbo |
Safety
Standard brake unit
(front axle)
Active safety: braking system.
Always quick when you have to be slow.