It's not the turbo. Your turbo is only spinning when there's a load, and you've got your foot deep into it.
What you are hearing is you Secondary Air Injection Pump. May be on it's way out, but you can hear it normally (although it's not that loud). It's an emissions only system, so it does not effect performance. It only runs when the engine is cold to flow additional air into your exhaust to more quickly heat up the cats.
So if it is going you'll get a CEL, and hear a heart stopping beep accompanied by "EMISSIONS WORKSHOP!" on your dash display, but it aint no thing but a chicken wing, so don't worry. It only an annoyance and can be delt with once you get sick of the light.
Another Jason from Philadelphia, weird. Anyway, yeah I have an '02 1.8t and during the first 30 seconds or so of a cold start, at least every morning, there's like a propeller sound on top of the usual engine's low hum. I think it goes away sooner if I drive immediately. The sound persists and increases in sync with the RPM and engine sound as I drive until it suddenly goes away and I'm left with the usual wonderful sounding purr and whistle of my little turbine engine. I don't know if it's always done this, as I've only owned the car for a month and my dad owned it before me.
How long have you had the car? The SAIC is what is loud on startup - it is always very loud but then again so is the 1.8T engine until it revs down. The SAIC will get really loud when it's on its way out tho.
Mine sounds like a vacuum. Sequence of events under my hood on cold start:
* starts, if it's below 30 degrees I get a ratcheting sound for 1 - 1.5 seconds (that the dealer can't reproduce, doesn't sound like valves, sounds like a chain dragging over something). Engine generally loud
* engine slows to more normal speed after a little bit.
* vacuum-sounding noise on top of engine noise, RPM lowers slightly
* vacuum-sounding noise stops, idle smooth and engine VERY quiet.
I have the same noise untill it warms up, I just did the Timing and all belts...So I would think it could be the Acc tensioner, it would seem that this is a source of the problem from what I have read here and over at AW..
Plus you have a 2000 with an updated TB tensioner most likely, an that acc tensioner is famous for these noises from what I have heard, no pun intended
I have the same car, had the same problem last year. It was the secondary air injection pump. Have it checked and if it is, call VW of America & complain. Tell them you want this documented as a pattern failure part. They agreed to pay half of the total repair bill.
PS-Also have the dealer check out your combi valve--it 's failure often causes the pump failure.