key PORSCHE 911 TURBO 2004 4.G Information Manual

To apply these benefits efficiently
to the road, we required another
innovation in sportscar design: all-
wheel drive with Porsche Traction
Management (PTM). Using an
electronically controlled multi-plate
clutch, this intelligent technology
provides variable drive to each
axle. The front/rear split is con-
tin
uously adjusted based on current
road conditions and driver inputs.
Although biased towards the rear,
the front receives more power
whenever the situation requires.
Porsche Traction Management
is specifically designed to
optimise driving dynamics. The
additional traction provided by
both the all-wheel drive system
and PTM represents a major
improvement in active safety,
especially in the wet or on snow.
Another benchmark technology
on the new 911 Turbo is the
standard braking system. The
front and rear discs have a
generous diameter of 350 mm.On the optional Porsche Ceramic
Composite Brake (PCCB), the
front diameter is increased to
380 mm.
Other standard features on the
new 911 Turbo include a new
evolution of Porsche Stability
Management (PSM) as well as
Porsche Active Suspension
Management (PASM) featuring
electronic damper control.
A
limited-slip differential is available
for the rear axle as an option.
For even greater performance, the
car can be equipped with the
optional Sport Chrono Package
Turbo. Key features include
an ‘overboost’ function which
provides as much as 60 Nm
of additional torque under
acceleration. When the throttle
is fully open, the boost pressure
is increased temporarily by
approximately 0.2 bar. The
electronic throttle map is
also adjusted to give a more
dynamic response to pedal
inputs.
Other modifications when ‘Sport’
mode is selected include a major
rise in the trigger threshold used
by Porsche Stability Management
(PSM). The all-wheel drive system
featuring PTM provides a similar
increase in driver involvement
by sending a greater proportion
of drive torque directly to the
rear wheels. PASM provides a
stiffer suspension setup enabling
faster turn-in and better road
contact.
Another major development
on the new 911 Turbo is the
car’s lightweight design and
construction. The doors and front
lid are made from aluminium
which offers a range of benefits
in terms of both performance
and economy. Every gram of
weight on every component
is there for a specific reason.
As a result, the standard model (with six-speed manual gearbox)
weighs just 1,585 kg. Even more
impressive are the power-to-
weight ratio of 302.8 bhp per
tonne and surprisingly low fuel
consumption.This powerful potential is, of
course, matched by exemplary
ride quality on every type of
road. This rare combination of
performance and comfort is one of the distinguishing features
of the 911 Turbo.
· 18 ·· 19 ·The new 911 Turbo |
The new 911 Turbo

Tiptronic S, the new 911 Turbo
requires just 3.7 seconds to
reach 100 km / h (62 mph), and
just 12.2 seconds for 200 km / h
(124 mph). Facilitating this
performance is the additionaltraction provided by the new
electronically controlled all-wheel
drive system (see page 48).
In appropriate track conditions,
the car’s maximum speed is
310 km / h (193 mph).
· 29 ·The new 911 Turbo |
Drive
Every 911 shares the same
fundamental engine charac-
teristics. Key among these are
the ‘flat-six’ cylinder layout
and rear-mounted installation.
There is, however, one essential
feature that is unique to the
911 Turbo. The twin turbocharger
system that gives the car its name
now includes Variable Turbine
Geometry (see page 32). Thus
equipped, the 3.6-litre engine
develops 353 kW (480 bhp) at6,000 rpm. Weighing 1,585 kg,
the standard 911 Turbo (with
manual gearbox) has an excellent
power-to-weight ratio of
302.8 bhp per tonne. Specific
power output is 133 bhp per
litre of engine displacement.
Maximum torque is a phenomenal
620 Nm, rising to 680 Nm with
the overboost function in the
optional Sport Chrono Package
Turbo (see page 60). Thanks
to VarioCam Plus (see page 38)and the new turbocharger system,
all of that torque is fully available
between 1,950 and 5,000 rpm.
The resulting acceleration is
inspirationally quick. Equipped with
· 28 · · 27 ·The new 911 Turbo |
Drive
Engine.
Heart and soul of the new 911 Turbo.
911 Turbo engine

Lightweight design.
The six-cylinder boxer engine is
a highly compact unit offering
excellent cylinder charging and
torque characteristics as well
as optimum balance and minimal
vibration. With the cylinders
arranged horizontally on either
side of the crankshaft, the
layout is key to the car’s low
centre of gravity.
The alloy crankcase consists
of two main sections, each
containing one bank of cylinders.
The crankshaft runs in eight main
bearings and is driven by forged
connecting rods. For optimum
durability, we’ve used forged
aluminium pistons running in
Nikasil-coated aluminium liners
and featuring individual oil-spray
cooling. Key benefits include lower
frictional resistance and longer
service life.
The cylinder heads are made
from a lightweight alloy which
is extremely resistant to high
temperature. Each bank of
cylinders has two overhead
camshafts driving a set of four
valves – two inlet and two exhaust
– on each individual cylinder.
The valves are arranged in a ‘V’
configuration and feature a highly
efficient dual-spring design.
Engine performance is further
enhanced with the aid of bothVariable Turbine Geometry (VTG –
see page 32) and VarioCam Plus
(variable valve timing and lift
on inlet side – see page 38). The
benefits are not only greater
power and torque, but also better
fuel economy and lower emissions.
Dry-sump lubrication.
This classic dry-sump system
with separate oil reservoir
ensures consistent oil pressures
throughout the engine. In doing
so, it compensates for even the
most extreme and prolonged
gravitational loads.
After passing through the engine,
every drop of oil is returned
directly to the external reservoir.
The flow is driven by two pairs of
scavenge pumps in the cylinder
heads and a further two pumps in
the crankcase. Gas is removed
from the returning oil by means of
a defoaming device in the
reservoir. As a result, the oil
level in the reservoir remains
virtually constant at all times.
The oil is returned to the
lubrication points in the engine
by means of a dedicated
oil-feed pump. With a further
scavenge pump in each of the
twin turbocharger units, the
new 911 Turbo has a total of nineseparate pumps to drive the
lubrication system.
The oil level can be checked from
inside the car via the standard
on-board computer. This solution
is not only cleaner and more
convenient than a conventional
dipstick, it is also significantly
more accurate.
· 30 ·· 31 ·The new 911 Turbo |
Drive
Main rotating assembly and valve gear

vanes are opened further. By
varying the vane angle, it is
possible to achieve the required
boost pressure over the entire
engine speed range. As a result,
there is no need for excess-
pressure valves as found on
conventional turbocharged
engines.
· 34 · · 32 ·· 33 ·The new 911 Turbo |
Drive
Variable Turbine Geometry (VTG).
Creating the optimum turbo for every scenario.
known as ‘turbo lag’, means there
is virtually no turbocharging effect
at lower engine speeds. To
overcome this problem, the twin
water-cooled turbochargers on
the new 911 Turbo feature Variable
Turbine Geometry (VTG). With
this technology, the gas-flow from
the engine is channelled onto Larger turbo units, which create
lower back-pressure at higher rpm,
take considerably longer to spin
up under power due to the large
cross-sectional area and relative
inertia of the heavier turbine.
Generally, this type of turbo will
only be effective in the medium
rpm range. This phenomenon,
Turbocharger guide vane adjuster Turbocharger with Variable Turbine Geometry (VTG)
up easily to its optimum speed.
The key disadvantage of using
a smaller turbo is that the back-
pressure generated at higher
engine speeds causes a significant
reduction in performance.
Resistance is caused by the smaller
cross-sectional area through which
the exhaust is required to flow.
The 911 Turbo has always been
synonymous with performance.
Now the car is more capable than
ever thanks to a new twin turbo
system featuring Variable Turbine
Geometry (VTG).
On a conventional turbocharger,
the exhaust flow drives a turbine
that is connected to a compressor
in the air intake tract. By ‘squeezing’
the incoming air, the amount
of oxygen in a given volume isincreased. Since compression also
causes an increase in temperature,
the air must be passed through
an ‘intercooler’ unit. With more
oxygen present in each cylinder
charge, more fuel can be burnt
yielding greater energy. Since
higher exhaust pressures generate
corresponding loads on the intake
side, the intake pressure must
be carefully controlled in order
to protect the engine. On the new
911 Turbo, the ‘boost pressure’ islimited using ‘wastegate’ valves
that bypass excess pressure
around the twin exhaust turbines.
Another important factor is the
size of the turbo unit. Since a
smaller turbine has a lower mass,
it generally responds more quickly
to increasing pressure, spinning
the turbines via electronically
adjustable guide vanes. By
changing the vane angle, the
system can replicate the
geometry in all types of turbo,
large or small.
With Variable Turbine Geometry
(VTG), it is possible to achieve
higher turbine speeds, and thus
higher boost pressure, at lower
engine rpm. Cylinder charging issignificantly improved, with a
corresponding increase in both
power and torque. Maximum
torque is reached at lower rpm
and is retained across a wider rev
range. A full 620 Nm is available
from as low as 1,950 rpm up to
5,000 rpm. Every throttle input is
met with exceptional response
and phenomenal acceleration.
When the boost pressure reaches
its maximum value, the guide

Engine cooling.
The 911 Turbo engine features
cross-flow water cooling with fully
integrated coolant management.
This technology ensures a
consistent flow of coolant to each
of the engine’s cylinders. All
coolant passages are integral to
the block, thus eliminating the
need for external hoses. Each
cylinder receives a fresh supply
of coolant which has not been
pre-warmed by the engine. As well
as improving reliability, this
helps to minimise maintenance
requirements. Waste heat from
the oil is transferred to the
coolant via two oil/water heat
exchangers. The coolant is routed
through twin radiator modules
ahead of the front wheels and a
centrally placed unit in the nose.
Engine management.
Optimum performance is assured
at all times with the aid of
the Motronic ME7.8.1 engine
management system. On the new
911 Turbo, this powerful ECU is
responsible for all engine-related
functions and assemblies (see
diagram). Key among these are
the Variable Turbine Geometry
(VTG), VarioCam Plus and
electronic throttle system – one
of the essential prerequisites
for the standard Porsche Stability
Management (PSM). The results:
optimum economy, emissions
and performance, regardless of
driving style.Another important task performed
by the engine management
system is cylinder-specific knock
control. By preventing pre-ignition
at high engine speeds, this
function can avert costly damage
to the pistons and cylinders. Since
temperatures tend to vary in
different parts of the engine, each
cylinder is monitored separately.
If a risk is detected, the individual
ignition timing is adjusted.
The EU-compliant on-board
diagnostics system provides
continuous fault detection and
early warning for the exhaust
and fuel supply systems. The
resulting benefits are active
prevention of harmful emissions
as well as consistent rates of
fuel consumption.
· 40 ·· 41 ·The new 911 Turbo |
Drive
Input data Used to regulate /control
Engine management system
(Motronic ME7.8.1)
Engine load
Pressure upstream from throttle
Throttle-valve angle
Engine speed (from crankshaft)
Camshaft phase angles
Throttle-pedal position
Lambda signal
Knock sensor signal
Ignition
Fuel injection
Throttle valve
Heating elements in lambda sensors
Fuel pump
Fuel-tank venting
CAN interface to
all-wheel drive control unit CAN interface to transmissionMoment interface to Porsche
Stability Management (PSM)
VarioCam Plus
– camshaft phase angle
– valve lift control
Electronic controller for
Variable Turbine Geometry (VTG)
Bypass valve
Secondary air injection
Engine-bay fan
Starter
On-board diagnostics
Air-conditioning compressor
Interface to instrument cluster
Radiator fans
Vehicle speed
Air-conditioning settings
Engine immobiliser status
Clutch pedal switch
Ambient air pressure
Temperatures
– coolant
– airflow upstream from throttle
– engine oil
– air in engine compartment
– ambient air
Exhaust-gas temperature

using the automatic brake
differential (ABD) function. For
optimum traction, manual gearbox
cars can also be equipped with
an optional mechanical limited-slip
rear differential (see page 56).
Assisting PTM is a new and
specially uprated version of
Porsche Stability Management
(PSM – see page 58). Combined,
these systems ensure optimum
torque distribution – and thus
optimum drive – in every type of
road scenario, including high-
speed straights, hairpin bends and
challenging, variable-grip surfaces.
Under heavy braking where ABS
is required, the multi-plate clutch
severs all front drive so that
each front wheel can be controlled
separately
by the ABS without
being influenced by the rear wheel
dynamics.
The traction benefits of the new
electronically controlled system
are particularly apparent in
the wet or on snow. In these
conditions, the new 911 Turbo
offers breathtaking acceleration.
In short, PTM offers greater
active safety, greater performance,
and even more of the positive
handling and agility you’d expect
from a 911 Turbo.
· 49 ·The new 911 Turbo |
Drive
differential (ABD) and anti-slip
regulation (ASR).
The electronically controlled clutch
is used to vary the drive torque
transmitted to the front axle. The
previous 911 Turbo had a multi-
plate clutch filled with a viscous
fluid, which ‘passively’ determined
the front/rear torque split. On
this latest evolution, the fluid is
replaced by active, electronic
control.While the viscous-fluid system
responds to relative differences in
front/rear axle speed, the new
electronic clutch offers a more
direct response to changing road
scenarios. The status of the car
is continuously 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 acceleration of
the car, and the current steering
angle. The sensor data is analysed
in ‘real time’ by PTM, 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 transmitted to
the front axle. The integral ASR
function is also used to minimise
wheel-spin. When
cornering,
the system controls drive to the
front wheels in order to maintain
optimum lateral grip. On variable-
grip surfaces, traction is enhanced
· 48 · Electronically controlled multi-plate clutchAll-wheel drive system
Genuine high performance calls for
more than just a powerful engine.
It also requires an effective means
of applying that power to the road.
On the 911 Turbo, this is achieved
by means of permanent all-wheel
drive and an all-new version of
Porsche Traction Management
(PTM). The key mechanical feature
within the AWD system is the
electronically controlled multi-plate
clutch. Integral functions within
PTM include an automatic brake
Electronically controlled all-wheel drive with Porsche Traction Management (PTM).
The intelligent application of power and torque.

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

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.

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.