This site lists SAE technical papers pertaining to turbos. Check out papers #790312 and #840251 on the Ford 2.3 turbo, should make for interesting reading although dated (The first two numbers refer to the year of publ.) SAE papers are HEAVILY technical and can make most guys eyes cross and glaze over. But if you're really into it, have fun:
http://www.sjmautotechnik.com/sturbo.html