think i'll give it a try, ive even read about someone using a pressure switch to piggyback another injector so when it hits boost is whacks more fuel in on a capri,when it hits boost the pressure switches another injector on, not very accurate but apparently works, could rig something like this up to the 5th injector on the 3i, using this with the boost retard on the dizzy and it could be ok, its not going to cost me anything so i might do a bit of experimenting