The stock Map (manifold air pressure) sensor is accustomed to reading vacuum (part throttle/idle) and normal air pressure (WOT). It's not used to seeing positive pressure (boost). With some type of clamp on the MAP (either voltage, or with a missing link which doesn't let the map see boost), the map never knows you're going into boost. this keeps the computer happy. If it does see boost, it'll buck cuz it'll pull fuel(?) and won't let you boost. That's why you need to limit it.


BTW: wHat has an "H" in it ;-)


Brian