[Vwdiesel] 01 Golf TDi TURBO issues

[James Hansen]

> thanks Erik
> yes, the disconnect was post-turbo
> and yes, the turbo was 'boosting' that whole time, judging by the mess
> of oil all over everything
> but are you saying that the turbo puts out more air than the engine
> sucks in?

Normally, yes.

> i.e. how much 'suction' does the intake create, vs how much pressure
> does the turbo produce?

Enough to make boost pressure, hence more air goes there than is pulled in
by suction of piston displacement. If the intake produced more suction than
the supply, there wouldn't be any boost pressure now, would there. Boost
pressure refers to the oversupply of air, creating pressure in the intake
system, so the pistons don't have to suck air in, the air just follows them.
You're kind of saying something along the lines of a balloon sucking the air
out of your lungs as you blow it up. 

> by definition, since the turbo comes from the exhaust, and the exhaust
> comes from the intake, and the intake comes from pistons drawing down
> and sucking air in, due at least to friction losses, wouldn't turbo
> pressure inherently be lower than intake vacuum?

Don't forget the part about the burning fuel.
It's a heat engine, the exhaust volume is many times the intake volume
because of heating from burning fuel ( boyle's law), and volumetric change
from fuel and air changing through speedy oxidation to stuff that takes up
more room such as CO2.   The turbo takes a tiny portion of the available
waste heat, and uses it to run an air compressor that blows the manifold
full.

> and if that's the case, AND the pipe was disconnected, so at least SOME
> turbo pressure was spilling, wouldn't there be a fair amount of sucking
> happening at that disconnected pipe of whatever was floating around
> under the hood - dust, dirt, insects, loose screws, old oily rags? I'm
> lucky I didn't get sucked right out of the driver's seat

That's why you should wear your seat belt, you never know when a brake
booster line, or especially one of those lines used to actuate the climate
control flaps can come off. They are vacuum too, and that's like space,
where it would suck you right in. Pull you right out of your seat if you
aren't careful. Keep both hands on the wheel too.

Bugs, leaves, rocks, stray bricks, neighbor's cat all would get blown out of
the car. Post turbo line's under pressure, real pressure, far more than the
sucky part.
;-)
-james