Haha, we go through this topic so often. It has something to do with the air the BOV is dumping back into the intake has to match up with the fuel the computer is telling the car to give. So when you mess with that mixture, you get screwy results. I know it sounds badass, but if I were you put it back on. I know from experience. But If you intend on keeping it off, lemme know, I'll buy that dump pipe from you.
Matter of fact go here.
http://www.dsmstyle.com/forum/index.php?sh...=20&#entry42337