2009 PORSCHE 911 engine

The 911 Turbo Cabriolet and the
new 911 Turbo S Cabriolet.
If life is a journey, wouldn’t it be a
tragedy not to enjoy it to the full?
Perhaps it ’s this – admit tedly
somewhat philosophical – outlook
that best explains the desire for
an open-top 911 Turbo.
It ’s all about that intense expe -
rience of driving with the hood
down. Coupled with the impressive
way in which the 3.8-litre boxer
engines unleash their power.
Their performance figures are
identical to those of the Coupés.
Whether you choose 500 hp or

530 hp will depend on how much
value you place on engine power.

Both models have a drag coefficient
of 0.32 when the hood is closed.
When fit ted with the manual
gearbox, the 911 Turbo Cabriolet
sprints from 0 to 100 km/ h
(62 mph) in just 3.8 seconds.
With PDK and the Sport Chrono
Package Turbo with dynamic
engine mount system (standard
on the 911 Turbo S Cabriolet),
it takes even less time, just 3.5
se conds. Top speed is 312 km/ h
(194 mph). The 911 Turbo S
Cabriolet, equipped with PDK as
standard, demolishes the
100 km/ h (62 mph) barrier in

3.4 seconds and has a top speed
of 315 km/ h (196 mph). Besides the equipment that you
would normally expect to find on
a convertible car, the 911 Turbo
Cabriolet and 911 Turbo S

Cabriolet have the same standard
specification as their Coupé
counterparts.
To prevent body flexing as much
as possible, the body is designed
for high torsional and flexural
strength. As a result you get the
same precise, direct driving expe -
rience as you do in the Coupé
The 911 Turbo concept | Model range
911 Turbo S Cabriolet
models. Despite the slightly
heavier weight, fuel consumption
is comparable with that of the
Coupés.
The dynamic engine mount
system of the Sport Chrono

Package Turbo (standard on the
911 Turbo S Cabriolet, optional
on the 911 Turbo Cabriolet)
reduces oscillations and vibra -
tions and further improves ride
comfort. Where safet y is concerned too,
the Cabriolet models meet the
most stringent requirements.
These, too, have full-size airbags
for driver and passenger as

well as Porsche Side Impact

Protection (POSIP, page 72). The
safet y package is supplemented
by the ef fective roll- over system
(page 72) and reinforced A-pillars.
Interior of the 911 Turbo S Cabriolet in t wo -tone leather (Black and Cream)
· 22 ·· 23 ·

Engine with intercooler
The location of the six-cylinder
boxer engine was not up for

discussion. Neither was the use of
t wo exhaust gas turbochargers
with Variable Turbine Geometry
(V TG). These are permanent

fixtures in a successful concept.
But that was no reason for Porsche
engineers to rest on their laurels.
As a result, the 3.8-litre flat-six
engine now comes in t wo power
levels. The 911 Turbo models gene-

rate
368 kW (500 hp) bet ween
6,000 rpm and 6,500 rpm
and
650 Nm of torque bet ween
1,950 rpm and 5,000 rpm
(700 Nm for a temporary period
with the ‘overboost ’ of the optional
Sport Chrono Package Turbo w
ith
dynamic engine mount system).
In the 911 Turbo S models, a
modified valve control system

and an adaptation of the engine
management, combined with an
increase in maximum boost pres -
sure by around 0.2 bar, enable
the power unit to produce 390 kW
(530 hp) bet ween 6,250 rpm
and 6,750 rpm and generate a
permanently high torque of

700 Nm bet ween 2,100 rpm and
4,250 rpm to deliver even more
power to the road.
The consistently high low-end
torque of both engine variants
means that you can relax behind
the wheel – and relax about fuel
consumption, too.
The power concept of 1974:
a rear-mounted turbo -
charged engine. The effi -
ciency concept of today:
DFI, VarioCam Plus and
Variable Turbine Geometry.
Handling pressure demands composure.
Another example of why things are done a little bit differently at Porsche.
Engine.and emissions of the 911 Turbo S
models are as low as those of the
911 Turbo models, despite 30 hp
of extra power output. Both
engine variants comply with the
Euro 5 emissions standard.
This has required the use of
sophisticated technologies and
processes. Examples include
direct fuel injection (DFI),

VarioCam Plus, Variable Turbine
Fuel consumption is a considera
-
tion that at present is becoming
at least as important as perform -
ance figures. Including – perhaps
particularly – for sportscars of
this genre. Despite the increase
in power, the 911 Turbo with the
standard six-speed manual gear -
box uses 9 % less fuel than the
previous model. It has been pos -
sible to reduce CO
2 emissions by
up to 11 %. The fuel consumption Geometry (V TG) and the expan
-
sion intake manifold.
On balance, the engines of
the 911 Turbo and 911 Turbo S
models demonstrate power,
even when it ’s not just about
power in the traditional sense of
the word. The following pages
of the Performance chapter are
dedicated to this concept.
Performance | Engine
· 30 ·· 31 ·

Direct fuel injection (DFI).
On the 911 Turbo models, DFI
injects the fuel with millisecond
precision directly into the com-
bustion chamber at up to 140 bar
via electromagnetically actuated
injection valves, thus ensuring homogeneous distribution of the
air/fuel mixture and consequently
ef ficient combustion.
In the direct injection system, the
EMS SDI 3.1 engine management
system adjusts the injection

timing individually for each
cylinder and the injection quantit y
for each cylinder bank. This

optimises both the combustion
curve and fuel consumption.
Dual injection is implemented
at engine speeds of up to
3,200 rpm and triple injection up to 2,700 rpm to ensure faster
catalyst warm up after a cold
start and more torque in the
upper load range. The required
quantit y of fuel is distributed to
t wo or three successive injection
processes per cycle. DFI improves the internal cooling
of the combustion chamber by
forming the mixture directly in the
cylinder. This has made it possible
to increase compression (9.8
: 1),
resulting in more engine power
and even greater efficiency.
Integrated dry-sump lubrication.
Integrated dr y-sump lubrication
ensures a reliable supply of oil
even when a sport y driving st yle
is adopted. It also has additional
cooling functions.
The oil tank is located in the
engine, thereby eliminating the
need for an external oil tank.
A total of seven oil pumps ensure
the supply of oil. Six of those
return the oil from the cylinder
heads and exhaust gas turbo -
chargers directly to the oil sump
where a seventh oil pump feeds
oil directly to the lubrication
points in the engine.
To reduce drive losses and
increase ef ficiency, an electronic
on - demand oil pump is used.
This means that the oil pump is
operated at high power when
there is high demand and at low
power when there is low demand.
The result is an optimised oil
supply appropriate to require -
ments, lower fuel consumption
and fewer emissions.

Performance | Engine
· 32 ·· 33 ·

1
18
3
21
10
14
9
4
15
17
22
19
20
7
16
11
2
5
6
8
13
12 1. Crankshaft
2. Forged connecting rods
3. Forged aluminium pistons
4. Cylinder track
5. Camshaf t drive chain
6. Cam adjuster
7. Intake camshaf t
8. Switch tappets
9. Valves with valve springs
10. High pressure fuel rail
11. High pressure injectors
12. Individual ignition coils
13. Spark plugs
14. Air filter housing
15. Exhaust turbocharger with
variable turbine geometr y
16. Intercoolers
17. Pressure pipe
18. Throt tle valve
19. Expansion intake manifold
20. Cataly tic converters
21. Exhaust system
22. Oil filter
Lightweight design.
An alloy engine means less weight
and consequently reduced fuel
consumption. The intelligent
engine design also saves weight.
The alloy crankcase is divided
vertically, with the cylinders
integrated into the crankcase.
Forged connecting rods are used.
For optimum durabilit y, we’ve
used forged aluminium pistons
running in cylinders made from
an aluminium/silicon alloy and
cooled via individual oil-spray jets.
Integrating the camshaf t bearing
system fully into the cylinder
heads has also saved weight. The
subsequent low levels of engine
friction and the ef ficient design of the oil supply system have helped
to reduce fuel consumption even
further.

Performance
| Engine
Engine with air filter housing with a carbon -weave finish in the new 911 Turbo S models
911 Turbo engine
· 34 ·· 35 ·

Variable Turbine Geometry
(V TG).
The 911 Turbo and 911 Turbo S
models are straightforward, almost
mat ter-of-fact, when it comes
to handling power. V TG has con -
tributed enormously to this.
The variable turbine geometry of
the t win water-cooled exhaust gas
turbochargers goes a long way
to resolving the conflict of aims of
normal turbochargers. With this
technology, the gas flow from the
engine is channelled onto the
turbines via electronically adjust -
able guide vanes. By changing
the vane angle, the system can
replicate the geometry in all
t ypes of turbo, large or small,
and thus achieve the optimum
gas-flow characteristics. The
guide vanes are controlled by the
engine management system.
The result is a high turbine speed
– and therefore higher boost
pressure – even at low engine
rpm. With more air available, the
combustion is increased, yielding
greater power and torque.
Maximum torque is reached at
lower rpm and is retained across
a wider rev range. Both engine
variants deliver a torque of just
650 Nm from as low as 1,950 rpm.
In the case of the 911 Turbo
models, this torque is available
up to 5,000 rpm. The increased
maximum torque of 700 Nm in
the 911 Turbo S models is avail -
able bet ween 2,100 rpm and
4,250 rpm.
When the boost pressure reaches
its maximum value, the guide
vanes are opened further. By var -
ying 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.
In the 911 Turbo models, engine
performance can be further
enhanced by selecting the SPORT
but ton on the optional Sport
Chrono Package Turbo. Under

full acceleration, the maximum boost pressure in the lower and
medium speed ranges is tempo
-
rarily increased by approximately
0.2 bar. As a result, engine torque
is temporarily boosted by 50 Nm
to a maximum of 700 Nm. The
911 Turbo S models, by contrast,
are configured to operate with a
higher boost pressure level, which
means that their maximum torque of 700 Nm is available for an
unlimited period.
These values are sure to impress.
Yet, combined with the fuel
economy achieved despite the
high power output, they are
even more impressive. Because
power alone is not enough.
Guide vanes closed
Guide vanes open
Performance | Engine
Variable Turbine Geometry (VTG)
· 36 ·· 37 ·

VarioCam Plus.
VarioCam Plus is a variable valve
timing system on the inlet side
which also features t wo -stage
valve lift. For excellent smooth-
running performance, bet ter fuel
economy and fewer emissions.
And greater power and torque.
The timing of each valve is step-
lessly and electro -hydraulically
controlled by means of a rotary
vane adjuster.
For optimum responsiveness
during the warm-up phase,
VarioCam Plus will select the
higher valve lif t set ting and retard
valve timing. At medium revs
and low engine loads, the lower
valve lif t set ting is selected
and timing advanced in order to
reduce fuel consumption and
emissions. For maximum power
and torque, the higher lif t set ting
is selected and the timing of the
valves is advanced.
Engine management.
The EMS SDI 3.1 engine manage -
ment system ensures optimum
performance at all times.
It is responsible for all engine-
related functions and assemblies,
resulting in improved fuel
economy, emission levels and
performance, regardless of
driving st yle.
Another important task performed
by the engine management
system is cylinder-specific knock
control. Since conditions tend
to vary across the engine, each
cylinder is monitored separately.
If a risk is detected, the individual
ignition timing is adjusted to
protect the cylinders and pistons
at high engine speeds and loads.
The EU-compliant on-board
diagnostics system provides

continuous fault detection as well as early warning for the exhaust
and fuel supply systems. This
actively reduces harmful emissions
while maintaining consistent rates
of fuel consumption.
Ignition system.
The ignition system is a static
high-voltage system. Each indi -
vidual spark plug has a separate
ignition coil, ensuring perfect
combustion every time.
Performance | Engine
VarioCam Plus
· 38 ·· 39 ·

Expansion intake manifold.
More power for less fuel. What
sounds absurd is sometimes
quite simple. You just have to
have the nerve to question
prin ciples that are seemingly
writ ten in stone.
The 911 Turbo and 911 Turbo S
models have an innovative expan -
sion intake manifold that was
used for the first time on the latest
911 GT2. Its unique operating
principle is unlike any thing ever
featured on existing induction
systems. Our ‘expansion’ intake
manifold is a radical development
that is the polar opposite of the
resonance principle used on con -
ventional turbocharged engines.
A resonance manifold increases
engine output by forcing addi
tional
air into the combustion chambers.
To do this, the manifold is designed
in such a way that the air – which
vibrates due to the action of the
valves – is in a compression phase
as it passes through the inlet ports.
Unfortunately, compression not
only increases air volume, it
also increases air temperature
and this has a negative effect
on ignition.
Our expansion manifold simply
turns that principle around. The
internal geometry is radically
different from that on a resonance
intake system. Key modifications
include a longer distributor pipe,
with a smaller diameter, and
shorter intake pipes. As a result,
the air is in the expansion phase
as it enters the combustion

chambers. Since expansion always
cools, the air/fuel temperature is
lower and ignition is significantly
improved – thereby increasing
performance.
Of course, the amount of air that
enters the engine under expan -
sion is less than it would be under
compression. To compensate
for this, we’ve simply increased
the boost pressure. The resulting
increase in temperature – again
through compression – is immedi -
ately offset by the uprated inter -
coolers. Instead of hot compressed air
entering the combustion

chambers, we now have cooler

air generating more power and
torque. As a consequence, there
is a major improvement in engine
efficiency and therefore lower fuel
consumption even under heav y
loads and at high revs.
As we said, sometimes you just
have to question established
ideas.
Exhaust system.
The exhaust system is made
from stainless steel. Its cataly tic
converters are extremely heat-
resistant, yet quick to reach
temperature – and thus optimum
performance – when the engine
is started from cold.
Advanced exhaust gas technology
ensures compliance with stringent
emissions standards, e.g. Euro 5
in EU markets, LEV II/ LEV in the
USA.
Servicing.
The 911 Turbo and 911 Turbo S
models are designed for a long
life. A self-adjusting belt drives
the generator, power-steering
pump and air-conditioning com -
pressor. Valve clearances are
adjusted hydraulically, thus avoid -
ing the need for any adjustment
work. The camshafts are driven
by timing chains that require
no maintenance and the ignition
system, with the exception of
the spark plugs, is also mainte -
nance-free. The cars come with
a t wo -year unlimited mileage
w a r ra n t y.
The long service intervals (see
separate price list) keep costs
and labour times down and save
resources, since fewer service
products and consumable parts
are used.
Performance | Engine
911 Turbo engine and exhaust system
· 40 ·· 41 ·

Porsche Doppelkupplung (PDK).
Derived from motorsport, PDK,
which is standard for 911 Turbo S
models and optional for 911 Turbo
models, achieves one thing
above all else: it provides the
perfect balance bet ween uncom -
promisingly dynamic performance
and exceptional levels of comfort.
It ’s purely about point of view.
The driver’s especially.
PDK, with both a manual and an
automatic mode, enables
extremely fast gear changes with
no interruption in the power flow.
For improved acceleration and significantly lower fuel consump
-
tion – without having to dispense
with the advantages of an auto -
matic.
The driver experiences a sportier,
even more dynamic drive with
more agilit y. Depending on driving
st yle, gear changes range from
exceptionally comfortable to
exceptionally sport y.
Manual gear changes are per -
formed using PDK’s ergono-
mically
designed gear lever or
alternatively, on the 911 Turbo
models, using the switches on
the three-spoke sports steering
wheel: nudge forwards to change
up, pull back to change down.
Fit ted as standard on 911 Turbo S
models and available as an option
for 911 Turbo models is the three-
spoke sports steering wheel
with gearshif t paddles, which is
also capable of operating PDK.
With its motorsport-derived gear -
shif t logic, you pull the right-hand
paddle to shift up and pull the
left-hand paddle to shift down.
PDK has been specially tuned
to the characteristics of the
911
Turbo models and the new
911 Turbo S models. It has seven
gears at its disposal. Gears 1 to 6
have a sports ratio, with the top
speed being reached in 6th gear.
The 7th gear has a long ratio and
helps to reduce fuel consumption
even further.
PDK is essentially t wo half-
gearboxes in one and thus
requires t wo clutches –
designed as a double wet
clutch transmission.
The principle is simple: the
transmission ensures that
the extraordinary engine
power isn’t manifested as a
blaze of noise and smoke.
Unless that’s what you really
want.
Calm. Storm. Which way
round is up to you.
Transmission.
Porsche Doppelkupplung (PDK) gear selector Power flow in 1st gear
Power flow in 2nd gear
Performance | Transmission
· 42 ·· 43 ·