[Vwdiesel] Newbie Question

[LBaird119 at aol.com]

> I asume that TDI stands for turbo direct injection or thereabouts.
> How come I don't hear a turbo? (can't see anything under that huge plastic
> cover VW seems to love). Should one consider a turbo spool down/cool down
> period in some situations? I don't recall even seeing a mention of turbo
> in the owners manual.  What am I missing?
> 

  You have to get under the car and almost remove the belly pan to see it.
You don't hear it partly because they don't want you to (non-diesel motoring 
public wouldn't want to hear that "whining" noise).  The other part is if 
your 
exhaust is restrictive at all, it tends to muffle the sound pretty heavily.
James changed his exhaust, he could testify as to whether opening it up 
made the turbo audible.  Also they tend to be audible in the cabin under 
certain load and rpm condition anyway.  Resonance frequencies, hearing 
range and so on.  You hear them on the big trucks mostly because the 
exhaust is right there as well as the turbo itself.  Listen at the exhaust 
and you can often hear a whirr even at idle.  
  If you pull in somewhere "hot" meaning just topped a mountain pass, 
passed a bunch of traffic, heavily loaded, etc and want to pull over then 
you'd be best off to let it idle a minute or two.  If you end up taking an 
off ramp, stopping, turning, going a way and then parking, you've already 
been "cooling off" since you let off the throttle to slow down.
     Loren