Thanks for not tearing into this noob too badly! I had actually considered the altitude as URD is practically sea level MD, where I'm in OH is about 800ft. I figure that's not a big enough change, but my regular runs down to the Blue Ridge put me up to 2500ft at some points. Dragging a heavy vacation load (3000lbs boat/trailer, plus a dozen guns in hard-side cases, plus 10k rds of ammo, plus a week's worth of clothes) for vacation up some 8% grades on a 95F day and 90% RH that's got to be a significant difference. It's the lack of power there which drove me to the SC in the first place.
I did notice that the URD kit included both a replacement fuel pump and 7th injector setup. I attributed the higher kit cost partly to this, though figured the requirement for additional fuel was driven by a higher boost level. More air needs more fuel right? I never got around to the wide-band O2 or boost gauge (got de-reailed by possibility of converting to MAP over MAF), but would certainly be interested in a comparison between the two kits.
From what I understand the impellers on the OEM fuel pumps were soaked in a chemical agent too long. That left the impellers porous, able to absorb gasoline, and which compromised their structural integrity. Which means the impeller can break, or at best the holes allow fuel to flow through the impeller blades reducing output capacity. Replacing the pump with the correction may improve the flow over what it was, but is not the same as replacing the pump with something which has a higher fuel flow. I know
URD has pump kits, and you can request any of those pumps with your SC kit for an upcharge.
IIRC the OEM is a 230L/hr pump, and the standard with the URD kit is the 255L/hr pump.
