Dang, I thought I put in a link. Go here to see what I'm talking about. Basically the turbo inlet is smaller at low RPM. Meaning that with less volume to fill, the pressure produced would be close to what it is at full throttle. As your RPM increases, the turbo inlet also increases so your engine doesn't get clogged up. It's like having a small turbo at low RPM and a big one at high RPM.

I didn't explain that very well but maybe you'll get what I'm sayin once you look at the site.

Keenan