Originally Posted by Tzu
You can increase the cells all you want, but there will be a limit in the DME where it will register a low rail pressure fault and put the engine in dead mode. Flashing the DME effectively negates this by setting rail pressure higher in the DME tables to begin with and will give the procede more (higher) amounts of wiggle room. Of course you can just mod it in the DME completely and set it to be bypassed in the procede.
He can find a happy medium by manipulating boost and OL table mainly. Reducing boost in the midrange won't effect your max acceleration by much and the procede can handle the top end through bias no prob IMO (I have not tuned RBs though). I am assuming he is not using ethanol.
Rail pressure won't matter really, because in the end its volume that will determine fault. Actually lower pressure would be better cause gives OL a larger volume range (per OL value) since the percentage change would be greater.