i have a feeling that my boost gauge is off by a pound or two. whenever i slowly get on it to build pressure i can hear the vented stock BOV going pshhhhh. i would think that the stock BOV would close fully when there is more pressure than vacuum(someone correct me if im wrong). well at 0 psi it still makes PSHHH noise, at 1 psi still and 2 still. isnt till about 3 lbs that i can hear the turbos whining and the PSHHHH noise stop. also when i hit about 2 lbs on the defi my PFC finally reads about -15 to -10ish. so there is actually more than one question here. can anyone address these?
kris

 

The PFC is known to display boost inaccurately.

How did you run the boost sensor for the Defi gauge? Did you plumb it straight off the UIM nipple? Is the map sensor installed upright? For what it's worth, I hear my turbos start spooling while I'm still in vacuum. Also, my Defi boost gauge is T-ed off the stock map sensor hose, so both map sensors are right next to each other. (The UIM nipple is used for the boost controller.)

 

defi gauge is plumbed into the UIM(is this wrong???) id like to try and get a more accurate reading if there is a way. i have the defi MAP about 12 inches from the nipple attatched to the fan relay bracket. wish i had a digi camera. next electronic might be an xbox though. enough about that. i hear that the PFC displays inacurately, but i hear the BOV releasing pressure while my defi reads above 0 psi. i think that is wrong. thanks for the info though ryenberg. its appreciated. im gonna go change the spot for the MAP to see if i get different readings.
kris

 

I believe that the standard location for determining boost pressure and vacuum is that nipple on the UIM. I don't know of a way to recalibrate the Defi gauge, but the manual does say that the less hose you use, the better (due to the rubber hose flex...which shouldn't be much, even if you're using 12" of it). Try another gauge there...maybe borrow a mechanical gauge from someone and see if it's reading the same. If so, then you're just boosting higher.

As for your BOV, mine does the same, but I don't think it has anything to do with the vacuum/boost for some reason. Unless I get on the throttle pretty hard, the BOV will continue to vent. Even if I ease the throttle on and keep on pushing it, unless I really get on it hard all at once it'll just keep venting. I've just guessed that it's kind of a POS

Patrick