· 25 · · 24 ·
The 911 GT2 |Drive
Lightweight design.
The six-cylinder twin-turbo boxer
engine is a compact unit offering
excellent cylinder charging and
torque-curve characteristics
as well as first-rate balance with
minimal vibration. The flat-six
design allows a low centre of
gravity with resulting advantages
for traction and driving dynamics.
The alloy crankcase consists of
two main sections, each contain-
ing one bank of cylinders. Thecrankshaft runs in eight main
bearings and is driven by forged
connecting rods. For optimum
strength and durability, we’ve used
forged aluminium pistons running
in Nikasil-coated aluminium liners
and cooled via individual oil-spray
jets. The results: lower frictional
resistance and a lengthy service
life – even when subjected to
heavy use.
The cylinder heads are made
from an extremely heat-resistantlightweight alloy. Each cylinder
bank 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’ formation and
have a highly efficient dual-spring
closing action enabling higher
engine speeds. Performance is
enhanced with the aid of both
Variable Turbine Geometry (VTG,
see page 28) and VarioCam Plus
(variable valve timing and lift on
the inlet side). The benefits are
not only greater power and
torque, but also better fuel
econ-
omy and lower emissions.
Dry-sump lubrication.
This racing technology uses a
separate oil reservoir to ensure
consistent oil pressures through-
out the engine, even during pro-
longed periods of lateral and longi-
tudinal loads. After passing
through the engine, every drop of oil is returned directly to the
external reservoir. The flow is dri-
ven by two scavenge pumps in
each cylinder head and a further
two pumps in the crankcase. Gas
is removed from the returning
oil via a defoaming device in the
reservoir. 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
911 GT2 has a total of nineseparate pumps driving the lubri-
cation system. The oil level can be
checked from inside the car via
the standard on-board computer.
The 911 GT2 is factory-filled with
Mobil 1 high-performance fully
synthetic oil. The exceptional
properties of this premium-quality
lubricant ensure reliable starting
even in the coldest conditions. It
also reduces wear and contributes
to the long-term durability of the
engine.
· 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
