2zeroes

On every 88 and 89 turbo I've driven, there is a mechanical buzzing/whirring noise you hear for a couple of seconds right after you start the car and drive off on 1st gear. The noise appears for a couple of seconds once the car gets moving. Anybody know what that noise is?

I know its normal but just wondering what that noise is.

Don't know if the 86 and 87's also make that noise as I've never driven any.