Terry:
Your new belts will tend to make a "turbo" or spooling sound when new. And, if they used certain types of belts, they can be louder than the more expensive belts Porsche certifies for use. I use Continentals (I think) and they make that whirring/spooling sound a bit. Not to worry.
You should have the tension re-checked and adjusted after about 1000 to 2000 "new" miles ( I do mine around 1000 becasue I track the car and the temps go up a bit). The thing to remember about the belts and tension is, when the motor gets hot, it expands a bit and puts additional tension on the belts. New belts stretch during this time. When it cools down, the belts loosen. Sometimes new belts seem to sound louder when the motor is cold .... that's because the tension on the belts is ever so slightly less than when the motor is hotter, and they may have had an initial "stretch." Normal stuff.
Also, I tend to have mine checked every time I tune up the car. It's a little extra cost, for a lot of engine insurance
, and peace of mind.
If you hear really loud belt noises, or click-clacking-tapping coming from your belt covers, get it all re-checked immediately. They may be way too loose, and you could seriously damage your valve-train if they jump or skip. Otherwise, some whirring/"spooling" sounds from new belts is okay.
These are my personal experiences with my car. I'm no expert, just a 944 owner. Talk to some of the local shops for additional info.
Good Luck!
Dan Chambers"It's
just a "well prepared" street car ... or a very, very well-mannered track car."
1983 SC #91 3.6L, "Black Pearl" Livery
1987 944 (gone but not forgotten)