9-5 Sport Wagon (9600) L4-2.3L Turbo (B235) (2003)
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Wastegate: Description and Operation
Brief Description
System Overview, 4-cyl.
Brief description
General
The turbo on the Saab 9-5 belongs to a new turbo family, the Garrett 17 (GT 17).
Turbocharging is one of the reasons why the engine has such a high torque at low rpm. In fact the engine achieves its maximum torque already at 1800
rpm, 280 Nm for the 2.3t Ecopower and 240 Nm for the 2.0t Ecopower. This makes the car very flexible and comfortable to drive.
Supercharging
Supercharging is achieved using a turbocharger. The engine exhaust gases are ducted through an exhaust turbine thus causing the turbine wheel to rotate.
A compressor wheel is mounted on the same shaft as the turbine wheel and rotates at the same speed as the turbine. The compressor wheel is located in
the engine air intake system and increases the pressure of the air entering the engine. In this way a larger mass of air enters the combustion chamber and
results in more efficient combustion, increased power and a greater torque. Thus the performance of the engine is comparable to a larger engine but it
retains the advantages of a smaller engine such as fuel economy, size, weight, environmental effects, etc. The turbocharger is designed to start working
already at low engine speeds and the engine can therefore give a high torque in the engine speed range that is used for normal driving purposes.
