gas mileage PORSCHE 911 2009 5.G Information Manual

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
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