ESP PORSCHE 911 GT2 2008 5.G Information Manual

· 13 · · 12 ·
The 911 GT2 |The 911 GT2
Always composed. Even in extremes.
Engineering the 911 GT2.
How do we know our limits?
Because we choose to
explore them.
The 911 GT2.The Porsche 911 GT2. The excep-
tion to the rule. Every new edition
has clearly exceeded everything
that has gone before. Designing a
911 GT2 requires a new approach
to old ideas. It means questioning
convention, crossing the limits,
thinking beyond the norm. It
means not being confined to
torque of 680 Nm is available
from 2,200 to 4,500 rpm. At
5,500 rpm, it is still higher than
650 Nm. The benchmark sprint
to 100 km / h (62 mph) is com-
pleted in 3.7 seconds. Maximum
speed is 329 km / h (204 mph).
For some, that number means
little on paper – but it all becomes
clear on the road. With a driving
experience – and an engine sound
– that can only be conceived in
the Porsche 911 GT2. Performanceand efficiency have both been
improved, mainly through changes
to the turbocharging system. The
flow-optimised turbines and com-
pressor units have been specially
adapted to the engine output and
offer a more effective turbochar-
ging process.
In addition, an expansion intake
system has been specially devel-
oped for the 911 GT2 (see page
32) which overturns all previous
principles of air supply to turbo road or track, straight or bend,
comfort or sports performance.
It means having the freedom to
leave what you know and examine
new possibilities. The result: our
most powerful road-going 911.
The source of that power is a
3.6-litre flat-six boxer enginebased on the current 911 Turbo.
Special features include VarioCam
Plus and twin turbochargers with
Variable Turbine Geometry (VTG,
see page 28) enabling faster
response at lower engine speeds.
Together, they generate even
greater power: a mighty 390 kW
(530 hp) at 6,500 rpm. Maximumengines. Equally effective is the
new rear silencer, now made from
ultra-lightweight titanium.
In the end, even we were impressed
with the power of the 911 GT2, as
we had not expected that so much
potential existed in the engine of
the 911 Turbo from which it is
derived. This was achieved because,
in terms of development, we
were prepared to go down new,
previously unexplored avenues.

· 16 ·· 17 ·
The 911 GT2 |The 911 GT2
being forced into the turbos,
there is less resistance from
the compressors and therefore
less back-pressure in the
exhaust, which means greater
engine performance.
The engine cover, featuring
the GT2 logo, is made from
lightweight glass-fibre reinforced
plastic (GRP). Twin titanium
tailpipes are elegantly incorpor-
ated within the rear apron design.
Warm air is vented from the braking power, with large air
intakes for improved air flow to
the central radiator and front
brakes. The integral air outlet
ahead of the front lid makes a
major contribution to front-enddownforce. The airstream from the
central radiator is channelled up
over the car, forcing the front end
downwards, thereby enhancing
balance and steering response.
The importance of air in the per-
formance of the 911 GT2 is also
apparent from the large intake
openings in the rear side panels
which supply the intercooler units.The most impressive view is also
the one that others will see most
of all: the rear. The fixed rear wing
with integral lip spoiler ensures
optimum stability at speed.
As the car accelerates and you’re
pressed into your seat, air is
forced through the intake openings
on the rear wing uprights and into
the engine turbocharging system.
This ‘ram air’ effect has a key role
to play in the exceptional efficiency
of the engine. Since air is already Power. Torque. Acceleration. All in
plentiful supply. Nothing else can
match that energy – except the
car’s design. A single glance is all
it takes to realise that fact.
The front end is aerodynamically
adapted for the high thermal
load of the engine and increased
Aesthetically. Aerodynamically. Resistance is futile.
Designing the 911 GT2.engine compartment via cooling
slits at the rear.
The combined effect of all these
aerodynamic modifications is a
drag coefficient of just 0.32 as
well as positive front and rear
downforce. Behind the wheel,
that means better grip, better
directional stability and excep-
tional handling characteristics.
Technically and visually, the
result is the same: a breathtaking
driving machine.

· 26 ·· 27 ·
The 911 GT2 |Drive
VarioCam Plus
Engine cooling.
The engine of the 911 GT2 features
cross-flow water cooling with fully
integrated coolant management.
This technology ensures a consis-
tent flow of coolant to each of
the engine’s cylinders. 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.
VarioCam Plus.
VarioCam Plus is a variable valve
timing system on the inlet side
which also features two-stage valve
lift. The benefits it provides include
greater power and torque at all
engine speeds, as well as excellent
running characteristics, better fuel
economy and fewer emissions.
Essentially, VarioCam Plus makes
two engines out of one. The first is
geared for normal road driving, thesecond for high-performance use.
The system switches seamlessly
between the two as the driver
inputs change. All operations
are controlled by the engine
management system. The results:
emphatic acceleration and
smoother running.
The two-stage lift mechanism
on each inlet valve consists of an
electro-hydraulically switchable
tappet. Each of the 12 tappets con-
sists of two concentric parts – anouter ring and a central shaft –
which can be locked together by
means of a pin. The system can
then vary the valve lift by using
two large profile cams on the outer
ring or a smaller cam lobe on the
central shaft. The timing of each
valve is steplessly controlled by
means of an electro-hydraulic
rotary vane adjuster at the head
of the corresponding camshaft.
To improve responsiveness during
warm-up in cold weather, VarioCam
Plus will select the higher valve
lift setting and retard valve timing.
At medium revs and low engine
loads, the lower valve lift setting
is activated and timing advanced in
order to reduce fuel consumption
and emissions. The economy of
the engine is particularly enhanced
at lower engine speeds. For maxi-
mum power and torque, the higher
lift setting is selected and the tim-
ing of the valves is advanced.This results in copious torque
and exceptional fuel economy,
particularly in comparison with
much larger engines offering
similar power output.

· 29 · · 28 ·
The 911 GT2 |Drive
turbine has a lower mass, it
responds more quickly to increas-
ing pressure, spinning 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.
On a conventional turbocharger,
the exhaust flow drives a turbine
that is connected to a compressor
on the intake side. By compressing
the incoming air, the amount
of oxygen in a given volume is
increased. Since compression also causes an increase in
temperature, the air must be
cooled in a device known as an
‘intercooler’. With more oxygen
present in each cylinder charge,
more fuel can be burnt, yielding
greater energy. Since higherexhaust pressures generate
greater loads on the intake side,
the intake pressure must be
carefully controlled in order to
protect the engine. This ‘boost
pressure’ is limited using ‘waste-
gate’ valves that bypass excess
pressure around the turbine.
Another important factor in
the system is the size of the
turbocharger. Since a smaller Porsche has a long and celebrated
tradition of using turbocharged
power on both road and track.
On the 911 GT2, we’ve
enhanced
this technology with Variable Turbine
Geometry (VTG).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,
known as ‘turbo lag’, means there
is virtually no turbocharging
effect at lower engine speeds.
Turbocharger with Variable Turbine Geometry (VTG)
Breathe easy – when holding your breath.
Variable Turbine Geometry (VTG).

· 34 ·· 35 ·
The 911 GT2 |Drive
Exhaust system.
The rear silencer and tailpipes
of the 911 GT2 are made from
ultra-lightweight titanium to re-
duce the weight on the rear axle,
and improve driving dynamics.
The exhaust leaves the engine
through high-performance
manifolds into separate tracts
for each of the two banks of
cylinders. Twin three-way catalytic
converters clean the two streams
before they converge in the main
silencer unit. The twin
titaniumtailpipes are fully integrated
within
the rear apron moulding. Large-
diameter tubes reduce back-
pressure
on the engine,thereby
increasing performance. The
catalytic
converters are close
to the engine,
enabling faster
warm-up and therefore improving
efficiency. When starting from
cold, the process is assisted by a
secondary air injection system.
A system of ‘Lambda’ or oxygen
sensors in each of the exhausts
provides continuous monitoring of engine efficiency. Data supplied
by one pair of sensors enables
the engine management system
to perform separate adjustment
of the air/fuel mix for each bank
of cylinders. A further pair of sen-
sors*, one on each tract, is used
to monitor the efficiency of the
respective catalytic converter. This
facility enables much more accu-
rate control of potentially harmful
emissions.
The exhaust system on the
911 GT2 produces a warm,
deep and bass-rich sound –
even when the engine is idling.
Fuel system.
Fuel is supplied to each of the six
cylinders using a sequential fuel
injection system. The timing of
each injection and the volume
supplied to each bank of cylinders
are controlled by the engine
management system. Adjustmentsare based on a range of variables,
including throttle position, engine
speed, boost pressure, coolant
temperature and exhaust gas com-
position. The results are optimised
combustion and fuel consumption.
A hot-film air mass sensor moni-
tors the volume and density of the
incoming air to ensure the best
possible air/fuel mix, regardless
of weather and altitude.
Ignition system.
The 911 GT2 features static
high-voltage ignition technology.
Separate coils on each of the
plugs with platinum electrodes
ensure perfect ignition every
time. The role of distributor is
performed by the engine manage-
ment system, which controls the
individual spark plugs directly,
for optimum performance and
minimum fuel consumption.
* Not in markets with leaded fuel.Exhaust system

· 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.

· 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.

· 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).

· 53 · · 52 ·
The 911 GT2 |Chassis
The steering system is extremely
direct and provides detailed
feedback from the road. This
high level of precision is very
advantageous in both racing and
normal road use. Thanks to the
precise front-axle kinematics andthe variable steering ratio, the
car responds to every movement
of the wheel.
An important feature of the
steering system is the variable
ratio gearing. Around the straight-ahead position, the ratio
is less direct, enabling smoother
manoeuvres, such as during
motorway driving. There is less
risk of excessive steering inter-
vention destabilising the car at
high speed. Naturally, the systemprovides excellent feedback as
well as the usual agility. As the
wheel is turned harder, the ratio
becomes more
direct and the
steering more responsive. This
variability is
particularly beneficial
in low-speed hairpin bends. The
energy-absorbing steering column
is a key safety feature since, in
the event of a front-end impact, it
enables a deformation path of
100 mm.The intermediate steering shaft is
made from aluminium, while the
protective tube and steering lock
housing are die-cast magnesium.
The standard three-spoke GT2
steering wheel features manual
height and reach adjustment.
Used in conjunction with the seat
adjustment options, it enables
every driver to find the ideal seat-
ing position.
Maximum precision, however powerful the performance.
Steering.