Tdci lacks turbo whistle

[extra_g]

On my UK holiday in 07 we hired a S-Max TDCi and loved it so much that after returning I bought an i30 (09) CRDi and on both the turbo whistles. Last year I bought a Focus (11) TDCi and it does not whistle. I don't believe there is any faults but am curious to know if anyone knows why the S-Max does and the Focus does not whistle. I believe they both have the same drive chains, unless they changed the turbo on the latter model Fords.
Even with bonnet up no whistle.

[CatonaPC©]

Originally Posted by extra_g

I believe they both have the same drive chains,

Turbos are driven by exhaust gases from the engine. They do not have drive chains.

[extra_g]

oops my mistake I meant to write drive lines.

[CatonaPC©]

Originally Posted by extra_g

oops my mistake I meant to write drive lines.

Turbos are not mechanically driven by the engine in any shape or form. The exhaust gases from the engine spins a turbine which in turn drives a rotor forcing air into the combustion chamber.

Superchargers do the same thing but in this case, they are driven by the engine by way of gears or belts.

The 'turbo whistles' you describe, I'm not familiar with.