The High Performance Honda Builder's Handbook Volume 1 (ISBN 1-884089-21-6) has a good chapter explaining this. You can get it here or at a bookstore. Good question - always research first. I don't know much about FI.
Do I have the space here to explain this...*LOL* Tell ya what a far easier way is CALL Tubonetics...That is their Compressor Map...They love to talk turbos and will be gladly to explain it alot better than I could...Hell I don't think I even can explain it....*LOL*
That graph contains much info. - it isn't really just one thing, and I don't think it can be easily explained - that's why I suggested the book - it has a much more detailed, plain english description than the link, and a bunch of other good info.