System Overview

System Overview

Brief description
The turbo in the Saab 9-5 belongs to a new family of turbochargers: Garett 17 (GT 17):

As distinct from a conventional normally aspirated engine, the supercharged engine fills the cylinders with a greater mass of air during the intake stroke, which means more efficient combustion, more power and higher torque. Engine performance is therefore comparable to that of a larger engine, but retains the advantages of a smaller engine as regards fuel economy, size, weight, etc.

The V6 has asymmetric turbocharging, which means that the turbocharger is driven by the exhaust gases from three cylinder (2-4-6). However, the turbo supercharges both cylinder banks.

Supercharging
Supercharging is accomplished by means of a turbocharger. The exhaust gases from the engine pass through a turbine rotor driven by the exhaust gases. The turbine rotor is mounted on the same shaft as a compressor wheel and rotates at the same speed. The compressor wheel is located in the intake system and creates a higher pressure, which leads to better filling of the combustion chamber. The turbocharger is so designed that it begins to work even at low engine speeds and therefore produces high torque in the rpm ranges used under normal driving conditions.