any sites that give a breakdown of drawing of the turbo :

 

http://www.holset.co.uk/files/4_4_1-...%20manuals.php

I have an H1C and HX35 manual from them, and it's pretty detailed.

 

Better yet can anyone show or tell how to make the H1C work harder with a little parts swaping or machine work. I know the tractor pull guys have done some internal "hot rodding" on their turbos because I have had them in the lathe before. It was so long ago I don't remember what I did or to what for that matter. I do remember it was a housing but that is all.

 

Thank you GMan07. That turbo manual website is great.

 

I think swank made some map width enhancement slots in one of his turbos once. Other than that HTT machines the backing plate on a lathe for their Stage IV upgrade. I don't know what else could be done besides a bigger compressor wheel & housing.