2004 PORSCHE 911 TURBO engine

· 13 ·The new 911 Turbo |
The new 911 TurboThe new 911 Turbo |The new 911 Turbo
In 1905, the Swiss engineer,
Dr. Alfred Büchi, filed the first ever
patent for a turbocharged piston
engine. The fundamental principle,
now a century old, remains
unchanged to this day: to use the
energy latent within the exhaust
flow from the engine to increase
overall performance.
The first turbocharged engine
was built in 1910 by the firm of
Murray-Willat. The concept was
embraced by the aviation industry,
which required an effective means
of compensating for the loss of
power caused by reduced oxygen
levels during high-altitude flight.Porsche was among the first
to recognise other benefits of
the technology, including higher
performance potential from
relatively small displacement
engines. This would lead to
the development of powerful
new engines with very modest
dimensions and weight.
The basic principle of a
turbocharged engine is to use
the exhaust gas flow to drive a
radial turbine which in turn drives
a compressor in the air intake
tract. The rotation of the
compressor generates a higher
intake pressure, thereby delivering
a greater amount of oxygen to
the engine. With more oxygen
available, more fuel can be burnt,
and higher performance can be
achieved. The density of the
air can be further increased by
cooling it prior to combustion.
The first ‘intercooler’ device on
a production Porsche appeared
in 1977 on the 911 Turbo 3.3.
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From a stroke of genius.
From strength to strength.
The new 911 Turbo.

· 14 ·· 15 ·The new 911 Turbo |
The new 911 Turbo
The second 911 Turbo, launched
in 1977, developed 300 bhp from
a 3.3-litre intercooled engine.
Brake performance was similarly
enhanced, combining four-piston
aluminium fixed calipers with
cross-drilled discs.
In 1993, Porsche launched the
final 911Turbo to feature dedicated
rear-wheel drive. Based on the
Type 964 platform, it used a
3.6-litre engine to achieve a major
boost in output to 360 bhp.
Its Type 993 successor, launched
in 1995, set a range of new
benchmarks in supercar perform-
ance. All-wheel drive provided
greater active safety as well as
better driving dynamics. The
system also had a rear-axle bias
that retained the familiar Porsche
handling characteristics. Twin
exhaust turbochargers offered
better response and a more
harmonious build-up of power. The
last 911 Turbo to have an air-
cooled engine, it offered maximum
output of 408 bhp from a
3.6-litre displacement.
The first water-cooled 911 Turbo,
the Type 996, made its debut
in the year 2000. Also equipped
with all-wheel drive, it used
VarioCam Plus to achieve a major
improvement in all-round fuel
economy. The engine capacity
remained at 3.6 litres, while
output rose to 420 bhp fo r a
maximum speed of 305 km / h
(190 mph). The Type 996 model
was the first 911 Turbo with the
option of Tiptronic S transmission.
The subsequent launch of the
Turbo S version saw a further
rise in output to 450 bhp.
Now, the evolution of this
remarkable car has reached a
new pinnacle of achievement.
Over the following pages, we
will explore every aspect of the
new 911 Turbo.The first Porsche racing car to
feature turbocharged power made
its debut in the early 1970s. The
12-cylinder engine in the legendary
917 used a twin turbo system to
achieve a colossal 1,000 bhp
.
In 1972, the 917/10 with 5-litre
turbo engine claimed the North
American CanAm
championship.
In the following season, the
917/30, developing 1,100 bhp
from a 5.4-litre unit, became the
most powerful racing Porsche of
all time.
This invaluable race experience
inevitably found its way into our
production
road car development.
Just one year later, in 1974,
the 911 Turbo was born. Preceded
as it was by the 1973 oil crisis, it
was considered a
bold undertakingby Porsche. As history would show,
it was the first of many surprises in
the evolution of this legendary car.
The original 911 Turbo featured
widened wheel arches as well as
specially developed front and rear
spoilers. These major aerodynamic
refinements were essential
requirements given the increased
engine performance. Developing260 bhp, the first 911 Turbo could
reach 100 km / h (62 mph) in as
little as 5.5 seconds. Maximum
torque output of 343 Nm was
unprecedented in a 3-litre engine.
This exceptional performance
necessitated a new gearbox
design featuring specially
reinforced gears. Thus began a
new type of Porsche that would
soon acquire mythical status.
911 Turbo 3.0 (1974), 911 Turbo (2006)

The primary objective for every
911 Turbo is to challenge the
limits of technical feasibility. Not
only in terms of performance
and dynamics, but also when it
comes to ride comfort. On this
latest evolution, we’ve completely
redesigned a number of systems
and components. The result builds
on the achievements of the
previous 911 Turbo – a car widely
acknowledged as the ultimate in
sportscar design.
As you would expect, the new 911 Turbo meets the highest
expectations in terms of engine
performance. The classic flat-six
unit develops 353 kW (480 bhp)
at 6,000 rpm from a 3.6-litre
displacement. Maximum torque
of 620 Nm is available between
1,950 and 5,000 rpm. To achieve
that capability, we’ve combined
VarioCam Plus with twin turbo-
charger units featuring Variable
Turbine Geometry (VTG) –
a totally new technology on apetrol-
engined car. With a standard
manual
gearbox, the new 911 Turbo
requires just 3.9 seconds to reach
100 km / h (62 mph). Equipped
with the latest optional Tiptronic S
transmission, the car is 0.2 seconds
quicker on the standard sprint.
Benchmark times to 200 km / h
(124 mph) are 12.8 and
12 . 2
seconds, respectively. Maximum
speed with either transmission is
310 km / h (193 mph).
One of the most important engine
technologies, appearing for the
first time on a Porsche, is Variable
Turbine Geometry (see page 32).
The main components on this
system are the adjustable guide
vanes which channel the exhaust
flow onto the turbines, enabling
higher turbine speeds at lower
engine rpm. The most difficult
challenge when developing this
technology was the high exhaust-
gas temperature of around
1,000 ºC, which is unique to a
petrol engine. This enormous
thermal load is considerably
greater than the 700 ºC typically
encountered on a diesel-powered
car. It was only possible to
bridge this gap using materials
developed for aerospace
applications. The primary benefitsof Variable Turbine Geometry
include faster response, higher
torque output from lower engine
speeds, and greater top-end
power. Maximum torque is also
available over a wider engine
speed range. By eliminating the
problem of ‘turbo lag’, the
traditional weakness of the
turbocharged engine is finally
a thing of the past.
· 16 ·· 17 ·The new 911 Turbo |
The new 911 Turbo
Pioneering technology, dependable results.
Engineering the new 911 Turbo.

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provide effective protection
against stone chips.
Elegantly matched to the exterior
of the car is the all-new wheel
design. The 19-inch forged alloys
have a standard two-tone finish
as well as wide, low-profile tyres.
The standard tyre dimensions
are 235/35 ZR 19 (front) and
305/30 ZR 19 (rear).
The interior of the car is equally
compelling and entirely designed
around the driver. The high-quality
surfaces include a full leather
finish on the standard electric
seats as well as the dashboard,
doors and rear side panels. Two
sports seat options are also
available, one featuring adaptive
adjustment. The standard
equipment package includes a
new gear-knob design – created
exclusively for the 911 Turbo –
· 21 ·The new 911 Turbo |
The new 911 Turbo
The extreme capability of the new
911 Turbo is elegantly enclosed in
a highly distinctive exterior. While
signalling the unique athleticism of
the car, it remains unmistakably 911.
The aerodynamics are exceptionally
well balanced, with positive
downforce at the rear. The drag
coefficient is remarkably low
at just 0.31. With its streamlined
shape and lightweight build,
the new 911 Turbo offers excellent
fuel economy as well as super-
lative performance.The standard Bi-Xenon headlights
with integral cleaning system
are compact, stylish and elegantly
incorporated within the new
front-end design. The front apron
moulding is an entirely new
development, featuring high-
performance LED indicators in
the outer air intake ducts. The
compact front foglights are
neatly positioned on the outer
edges of the front apron.
The side air intakes, to the rear
of the doors, provide optimum air
delivery to the twin intercoolerunits. Equally efficient are the
cooling air ducts to the front and
rear brake assemblies. This
enhanced cooling action is an
important factor in the excellent
performance of the standard
braking system.
The body of the car is much wider
across the rear than the front. A
generous wheel track is combined
with wider tyres to achieve
enormous lateral grip. The engine
lid is another totally new design
and features an integral bi-plane
rear spoiler. The
upper wing
element is automatically
raised at
approximately 120 km / h (75 mph)
and lowered at around 60 km / h
(37 mph).
The rear apron moulding has also
been redesigned to blend with
the rest of the car. The side air
outlets and fully enclosed twin
tailpipes are a further indication of
the power within. Black plastic
sills along the sides of the body
· 20 ·
Some say power is all about muscle.
For us, it starts with the mind.
Drive
Poised for action, yet always relaxed.
Designing the new 911 Turbo.
Rear wing retracted
Rear wing deployed
and a three-spoke sports steering
wheel featuring 40 mm of height
and reach adjustment.
The overall design of the
new 911 Turbo marks another
new phase in the ongoing
evolution of this remarkable car.
Wholly integral to the fundamental
vehicle concept, every detail
is a direct expression of power,
composure and comfort.

· 26 ·The new 911 Turbo |
Drive
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7. Exhaust-gas turbocharger
with Variable Turbine
Geometry (VTG)
8. Intercoolers
9. Pressure pipe
10. Throttle valve
(electronically actuated)
11. Exhaust system
12. Oil filter
13. Engine oil reservoir
(dry-sump lubrication)
1. Radiator module (left)
2. Radiator module (centre)
3. Radiator module (right)
4. Coolant pipe
5. Coolant expansion tank
6. Air filter
14. Generator
15. PASM damper
16. Tandem brake booster
17. 6-speed manual gearbox
18. Front differential
19. Fuel tank1. Oil scavenge pump
2. Oil-pressure pump (obscured)
3. Engine oil reservoir
(dry-sump lubrication)
4. Camshaft adjuster (VarioCam Plus)
5. Intake camshaft
6. Tappets (with hydraulic valve
clearance adjustment)
7. Valve springs
8. Intake valves
9. Nikasil-coated cylinder bore
10. Forged aluminium piston
11. Forged connecting rod
12. Crankshaft
13. Camshaft drive chain
14. Camshaft drive chain tensioner
with guide rail
15. Single-spark ignition coil
16. Spark plug
17. Exhaust-gas turbocharger with
Variable Turbine Geometry (VTG)
18. Exhaust system
19. Catalytic converter
20. Pressure pipe
21. Throttle valve (electronically actuated)
22. Plenum chamber
23. Ancillary drive belt
24. Fluid reservoir for
power-steering system
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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