2008 PORSCHE 911 GT2 Information Manual

· 37 · · 36 ·
The 911 GT2 |Drive
benefits, such as optimum econ-
omy, emissions and performance
in all driving scenarios.
One of the most important tasks
performed by the engine manage-
ment system is cylinder-specific
knock control. By preventing pre-
ignition at high engine speeds
and loads, this function can avert
costly damage to the pistons and
cylinders. Since temperatures
tend to vary across the engine,
each cylinder is monitoredseparately. If a risk is detected,
the individual ignition timing is
adjusted.
The on-board diagnostics system,
designed to European standard,
quickly detects any faults in the
exhaust and fuel system and
displays them during driving
via the car’s instruments. The
benefits include active prevention
of harmful emissions as well
as consistent rates of fuel con-
sumption.Input data Used to regulate /control
Digital engine electronics
(ME7.8.1 control unit)
Engine load
Pressure upstream from throttle
Throttle-valve angle
Engine speed (from crankshaft)
Inlet camshaft phase angle
Throttle-pedal position
Oxygen sensor signals
Knock sensor signals
Ignition
Fuel injection
Throttle valve
Heating elements in oxygen sensors
Fuel pump
Fuel-tank venting
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)
Recirculation valve
Secondary air injection
Engine-bay fan
Starter
On-board diagnostics
Air-conditioning compressor
Interface to instrument cluster
Radiator fans (front control unit via CAN)
Vehicle speed
Air-conditioning settings
Engine immobiliser status
Clutch pedal switch
Ambient air pressure
Temperatures
– coolant
– air upstream from throttle
– engine oil
– air in engine compartment
– ambient air
Exhaust-gas temperature
Engine management system.
The Motronic ME7.8.1 engine
management system facilitates
optimum performance at all
times. This high-precision ECU
controls all engine-related func-
tions and assemblies (see
dia-
gram), such as Variable Turbine
Geometry, VarioCam Plus and
the electronic throttle, one of the
key prerequisites for the standard
Porsche Stability Management
(PSM). This produces various

· 39 · · 38 ·
The 911 GT2 |Drive
The six-speed manual gearbox in
the 911 GT2 is specifically
designed for the high engine
performance. The individual ratios
are carefully matched to the spe-
cific characteristics of the engine.The gear-lever throw is short and
precise, enabling fast and
accurate gearshifts.
A typical feature of the 911 GT2
is the Launch Assistant – for maximum acceleration from a
standing start. The clutch and
accelerator are depressed when
the vehicle is stationary.
When a
boost pressure of approximately
0.9 bar is displayed in the instru-ment
cluster, release the clutchas
quickly as possible and maximum
a
cceleration automatically ensues.
Normally on a turbocharged vehicle
with manual gearbox, the boost
pressure under acceleration from
a standing start is relatively low.
The turbo effect is delayed as
the engine gathers speed and
the boost pressure starts to build.On the 911 GT2, this initial delay
is reduced. While the car is still
stationary, the fuel injection is
modified to help the engine reach
maximum output earlier. The boost
pressure is significantly increased
and the engine readied for a faster
start.
A specially designed traction
control system adapts the acceler-
ation procedure automatically
in the ECU to ensure optimum
traction. The clutch remains
engaged. This reduces load and
prevents high clutch wear. The
power is transmitted directly to
the road via the rear axle.
The gearbox is combined with
a cable linkage and dual-mass fly-
wheel offering added comfort and
precision. The close ratio spread
enables powerful acceleration
within the optimum engine power
band.
Steel baulk rings on gears two to
five ensure a precise gearshift
action even under extreme loads.Cooling is provided by an add-
itional oil-to-water heat exchanger
and spray lubrication. Both of
these features are essential for
durability in endurance racing
conditions.
Other standard features include
a limited-slip differential with
asymmetrical lock factor. Offering
better traction and handling
when exiting a corner, it applies a
higher proportion of drive torque
to the loaded outer rear wheel.
The term ‘asymmetrical’ means
that one lock factor is applied
when cornering under power
(28 %), and another when braking
for a corner (40 %).
Maximum response to minimum effort.
Transmission.

· 41 · · 40 ·
2
1
3
4
5
6
12
13
16
2022
21
19
7
9
1011
15
14
18
17
8
9
The 911 GT2 |Drive
1. Bi-Xenon headlights
2. Radiator module (left)
3. Radiator module (centre)
4. Radiator module (right)
5. Coolant pipe9. Intercoolers
10. Pressure pipe
11. Throttle valve
(electronically actuated)
12. Expansion intake manifold 6. Coolant expansion tank
7. Air filter
8. Exhaust-gas turbocharger
with Variable Turbine
Geometry (VTG)17. Generator
18. PASM damper
19. PCCB brake
20. Tandem brake booster
21. 6-speed manual gearbox
22. Sport bucket seat
13. Main silencer (titanium)
14. Tailpipe (titanium)
15. Oil filter
16. Engine oil reservoir
(dry-sump lubrication)

Chassis
An extraordinary car with
everyday capability.

· 44 ·· 45 ·The 911 GT2 |
Chassis
Rear axle Front axle
The 911 GT2 chassis is designed
for racecar-like performance on
every type of tarmac from motor-
way to track. The car rides about
25 mm lower than the 911 Carrera
and its lightweight build has
reduced overall weight as well as
the unsprung masses. Agile and
responsive, it is stable and secure– particularly during cornering
manoeuvres.
The front suspension with its
special wheel mounts has
McPherson spring struts with
the wheels mounted individually
on trailing arms and wishbones.
Each front wheel is preciselylocated, ensuring excellent
handling and directional stability
in all road and track scenarios.
Brake spoiler elements provide
efficient cooling for each of the
front brake units.The rear axle assembly consists
of subframe-mounted multi-link
suspension featuring LSA con-
struction (Light, Stable, Agile).
This lightened design featuring
an aluminium cross-member
is an important factor in the
exceptional dynamics of the car.
Ride height, camber, toe angle
and anti-roll bar settings can
all be adapted to individual circuit
characteristics, as befits a racing
Porsche.There is virtually no unwanted
movement between the suspen-
sion and body, thanks to special
features such as metal bearings
with ball joints on the front strut
mounts and rigid cross-members
at the rear. This reduced elasticity
and improved wheel location
enable better handling and turn-in.
The 911 GT2 has an electronic
variable damping system as
standard – Porsche Active Suspension Management (PASM,
see page 48).
This variable
damper system offers two basic
setup modes, ‘Normal’ and
‘Sport’.
Racetrack. Motorway. Wherever the road goes.
Chassis.

· 47 · · 46 ·
The 911 GT2 |Chassis
The 911 GT2 runs on one-piece
19-inch GT2 wheels with anti-
theft protection and wheel
centre caps featuring the GT2
logo. The wheels are extremely
light for their size due to their
special lightweight construction.The resulting reduction in unsprung
masses improves driving dynamics
and performance. Thanks to the
generous internal diameter of the
wheel, large brakes can be fitted
on the front axle. The wheels run
flush with the exterior of the carand come with special sport tyres
as standard.
The wheel dimensions are
8.5J x 19 ET 53 with 235/35 ZR 19
tyres (front) and 12J x 19 ET 51
with 325/30 ZR 19 tyres (rear).The 19-inch sports tyres provide
a large road contact patch.
They offer greater traction
under acceleration and braking,
greater precision in both handling
and manoeuvrability, as well as
higher cornering speeds on dry
road surfaces. In short: even
greater driving pleasure. Note:
increased risk of aquaplaning due
to lower tread profile.Tyre Pressure Monitoring (TPM),
included as standard equipment,
provides early warning of tyre
pressure loss. The driver is
informed via the on-board com-
puter display as well as a separate
indicator light. A tyre repair system
consisting of tyre sealant and
compressor with separate tyre
pressure gauge is also standard.19-inch GT2 wheel
Less weight. More road contact.
Wheels.

· 49 · · 48 ·
The 911 GT2 |Chassis
The 911 GT2 is fitted with Porsche
Active Suspension Management
(PASM), an electronic damper
adjustment system. This active
damping system offers continuous
adjustment of individual damping
forces based on current road
conditions and driving style.
The driver can choose from two
basic setup modes: ‘Normal’ and
‘Sport’. ‘Normal’ mode is designed
for general road driving and wet
circuit use. ‘Sport’ mode enables
greater lateral acceleration and
increases traction on the race-
track.
In either mode, the system
responds to changing loads by
automatically applying the optimum
rate on each individual damper
from a range of predefined options.Various sensors are used to
monitor the movement of the body
during acceleration, braking and
cornering manoeuvres, as well as
on poor road surfaces. The PASM
control unit then evaluates this
data and modifies the damping
force on each individual wheel in
accordance with the selected
mode. The results are a reduction
in pitch and roll as well as con-
sistent road contact on all four
wheels.
If ‘Sport’ mode is selected using
the PASM button identified by a
damper symbol, the suspension is
set to a harder damper rating that
is specially designed for perform-
ance driving. If the quality of the
road surface falls below a certain
threshold, the system immediatelychanges 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.
Rebound in ‘Sport’ mode –
damper piston with bypass
valve closedRebound in ‘Normal’ mode –
damper piston with bypass
valve open
Compression in ‘Normal’ mode –
damper piston with bypass
valve open
Compression in ‘Sport’ mode –
damper piston with bypass
valve closed
Redefining ‘normal’.
Porsche Active Suspension Management (PASM).

· 51 · · 50 ·The 911 GT2 |
Chassis
Some things never change,
including driver expectations of
a 911 GT2 : sports-oriented
performance, a direct response
and impressive power.
So Porsche Stability Management
(PSM) has been specially adaptedfor the 911 GT2. In addition to
ABS, the package includes two
automatic driver aids: stability
control (SC) and traction control
(TC).
Stability control (SC), which is
responsible for lateral dynamics,uses a range of sensors to moni-
tor the direction, speed, yaw
velocity (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 thecar begins to oversteer or under-
steer, selective braking is applied
on individual wheels to restore con-
trol in critical driving scenarios.
Traction control (TC), with its
integrated ABD (automatic brake
differential), ASR (anti-slip regula-
tion) and EDC (engine drag-torque
control) functions, is responsible
for the longitudinal dynamics of the
car. Configured for sports-oriented
driving, traction control improveshandling under acceleration on
surfaces with inconsistent grip.
It also prevents the rear from
‘stepping out’ if a wheel loses
traction under full power. The
trigger threshold is relatively high,
which means it is rarely employed
in normal dry conditions.
A unique feature of PSM on
the 911 GT2 is that the control
interventions are delayed and
can be disabled completely in
two stages – for deliberate per-
formance handling.
Stage 1 disables the stability con-
trol (SC) via the ‘SC OFF’ switch in
the centre console. In ‘SC OFF’
mode, the control system does
not intervene if the car goes off-
course in the lateral direction,
which means the throttle can
be used to help steer the car.
Traction control (TC) is still active
in this mode.
Stage 2 disables the traction con-
trol as well via the separate
‘SC+TC OFF’ switch, giving the
driver full command of the vehi-
cle. Another unique feature is the fact that stability control
remains disabled in stages 1 and
2 even when the ABS is required
under braking. Specially develop-
ed for the 911 GT2, this revised
system strategy means the car
can also be enjoyed to maximum
effect on the racetrack.
The anti-lock braking system
(ABS 8.0) is integrated in PSM
and remains active, irrespective
of which settings have been
selected. ABS ensures a relatively
short braking distance and thus
enhanced safety.
It’s good to know who’s in control.
Porsche Stability Management (PSM).