Piper PA-32R-301T SARATOGA S, Maintenance Manual

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TERM MEANING
Supercharge To increase the air pressure (density) above or higher than ambient conditions.
Supercharger A device that accomplishes the increase in pressure.
Turbo-Supercharger More commonly referred to as a “Turbocharger” this device is driven by a turbine.
The turbine is spun by energy extracted from the engine exhaust gas.
Compressor The portion of a turbocharger that takes in ambient air and compresses it before dis-
charging it to the engine.
Turbine The exhaust driven end of the turbocharger unit.
Wastegate The wastegate is a butterfly type valve in the exhaust by-pass which, throughout its
travel from open to closed. allows varied amounts of exhaust pressure to by-pass the
turbine, controlling its speed, hence the output of the compression.
Ground Boosted or These phrases indicate that the engine depends on a certain amount of turbocharging
Ground Turbocharged at sea level to produce the advertised horsepower. An engine that is so designed will
usually include a lower compression ratio to avoid detonation .
Deck Pressure The pressure measured in the area downstream of the turbo compressor discharge and
upstream of the engine throttle valve. This should not be confused with manifold
pressure.
Manifold Pressure The pressure measured downstream of the engine throttle valve and is almost directly
proportioned to the engine power output.
Normalizing If a turbocharger system is used only to regain power losses caused by decreased air
pressure of high altitude, it is considered that the engine has been "normalized".
Overboost An overboost condition means that manifold pressure is exceeding the limits at which
the engine was tested and FAA certified and can be detrimental to the life and perfor-
mance of the engine. Overboost can be caused by malfunctioning controllers or
improperly operating wastegate in the automatic system or by pilot error in a manual
controlled system.
PIPER AIRCRAFT
PA-32R-301/301T
MAINTENANCE MANUAL
81-20-00
Page 81-4
Reissued: July 1, 1993
4E4
TURBOCHARGER NOMENCLATURE.
Many unfamiliar terms may appear on the following pages of this manual. An understanding of these
will be helpful, if not necessary, in performing maintenance and troubleshooting. The following is a
list of commonly used terms and names as applied to turbocharging.