i understand that the oil is used to lubricate the shaft of the turbo, but i remeber reading somewhere that engine coolant is used to cool the turbo? is that true and if so how the heck does that work? does anyone have an image or something that i can see to try and figure this out?

someone posted a pic of a diagram that shows how it works in the B5 S4 forum... STFA good luck

<center><img src="http://pictureposter.audiworld.com/48790/img_turbine_16.jpg"></center><p>If you look closely you will see that there is an inner and outer cavity. Each cavity has an apearture where the supply lines feed fluids. The inner cavity is the oil cavity (lube) and the outer cavity is the water cavity (coolant).

A cool website to better understanding of this and other automotive inner workings is linked below.<ul><li><a href="http://www.howstuffworks.com">How-Stuff-Works</a></li></ul>