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 Side Impact Protection
System (POSIP).
POSIP, fit ted as standard, consists
of side impact protection beams
in the doors and t wo side airbags
on each side, namely a thorax
airbag located in the side of each
backrest and a head airbag incor-
porated within each door. Each
airbag has an approximate volume
of 8 litres, ensuring excellent
protection in the event of side
impact.
Additional safet y features include
the headrests which form an
integral part of each seat, an
energy-absorbing steering column,
three-point seat belts with height
adjustment (Coupés only), seat
belt pre-tensioners and force
limiters and energy-absorbing
elements in the dashboard.
Safety in the 911 Turbo
Cabriolets.
One fundamental principle at
Porsche is to provide high levels
of occupant protection, regardless
of whether the vehicle is a closed
or open-top design.
Torsional rigidit y and flexural
strength are exemplary for a t wo -
plus-t wo convertible. Body flexing
is minimal even on the most
poorly surfaced roads, ensuring
bet ter handling and greater
active safety.
Occupants are protected by an
automatically deploying roll- over
system if the vehicle were to overturn. Two spring-loaded roll-
over bars are neatly incorporated
behind each of the rear seats.
The roll- over sensor – part of the
airbag control unit – continuously
monitors the car’s pitch and roll,
contact with the road, as well as
lateral and longitudinal forces.
If the car were to overturn,
the top -padded bars would be
deployed instantly.
Of course, the 911 Turbo
Cabriolets also come as standard
with the Porsche Side Impact
Protection System (POSIP).
Responsibility | Safet y
· 72 ·· 73 ·
