[Vwdiesel] 01 Golf TDi TURBO issues

[Rolf Pechukas]

>> but are you saying that the turbo puts out more air than the engine sucks in?
> 
> Normally, yes.

but not if the turbo's not functioning, correct?

mine is not now, and has not been since the alternator 'repair'
no way to know when in the course of events it was disabled, but it's possible that boost was weak or non-existent at the time the pipe was left disconnected
in that case, intake suction could have been more of a issue, correct?

>> 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.

well, there would be a lessening of intake resistance...

> 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.

you're right, I HAD forgotten that
I was thinking simply that the displacement of the piston downward (intake) had to be equal to the piston upward (exhaust), so, barring valve opening differences, volume of intake and exhaust had to be more or less equal
but of course you're right - intake stroke is drawing in cold outside air, while exhaust is expelling hot, probably still expanding, combustion fumes
so even though the throw is the same, volume and pressure could be much higher
I get that

(for the record, though, theoretically the majority of the energy of the expanding combustion gasses goes into pushing the piston down, right?
and the better/more efficient the engine, the more completely that energy is spent
so the upstroke to exhaust, while expelling hot gasses, shouldn't be fighting any real pressure from sill-expanding fumes, should it?)

> 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.

like I said, I know nothing about turbos
thanks for the instructional

>> 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


yea, unless it's not working :(


anyway, all that said, I am thinking the best place to start is simply replacing lines
several people have said it's hard to see/find leaks, and the turbo simply not working since the repair seems fishy
who's to say they only left one thing disconnected?

any advice on what tubing to buy and where?

thanks again, all
Rolf in MA