Generally speaking, yes... hitting the turbo too soon will doom your chances of running the ball well. On inside run plays, I won't hit it until I clear the DL and even then, if there is a LB or SS close by I just don't bother w/ the turbo.
I think the same applies to screen passes. I learned you have to be patient and let the blockers get there-- except in the cases where the DL just so happens to read the screen perfectly and there isn't anything you can do about it.