you've limited his options to either a call or a fold. This is great because if he folds, and its a decent hand, you win that fairly juicy pot. If he calls you've still got like probably at least 11 outs to catch, which with the money in there, is worth going for. It doesnt really matter whether he calls or folds! (too much)
Im sure theres some kind of theory thing that applies to what you did, possibly from sklansky? i cant remember but it looks like it.
Except when he has a set of fours. not sure what happens then. Dont really like the thought of that.