Hope this is not a repost, or maybe I'm just late on finding this information but found some excellent info on the way a turbo charger works.

http://www.turbobygarrett.com/turbob...o_tech101.html
http://www.turbobygarrett.com/turbob...o_tech102.html
http://www.turbobygarrett.com/turbob...o_tech103.html

Some of the info is basic knowledge but it gets pretty advanced by the 3rd link.

 

Very good find and great visuals.