so wait...does ur safc actually change other parameteres or simply just fuel? and how do u monitor ur knock? add-on scan gauge? and also, wat kinda boost gauge...digital? analog? brand? lol, sorry just trying to figure out if ur just not running asmuch as u think, thats obv not the source of the problem here but...thinking ur running 21 and it being simple jumpy analogs and it actually being 19 is a big diff, hmmm, wat do u hold to redline? cause my digital shows a climb to 19psi , holds than goes to 15/14 at 6000