Porsche 911 Turbo User Handbook Manual page 40

The 911 Turbo I Environment
Instead of encapsulating the
engine in heavy sound-deadening
materials, Porsche engineers
eliminate noise at its source.
Rigid engine components,
light moving parts and tight
tolerances prevent vibration
and resonance. Highly durable,
stainless-steel mufflers minimize
exhaust noise throughout the life
of the car. What comes through is
the pure and distinct sound of a
Porsche engine.
Fuel system.
Key developments in the fuel
system include a further
reduction in the evaporation of
hydrocarbons. This is achieved
through a combination of an
active carbon filter and a specially
coated fuel tank. All the fuel lines
carrying liquid are made from
aluminum, while those carrying
vapors use multilayer plastic.
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