It's official, I broke my boost gauge in a fit of clumsiness. That really just pisses me off at me. It dropped out of the box onto the pavement on the way into the auto parts store, grrrr. Now I'm out fifty bucks and I don't want to shell out more right now for another one. Anyone got a cheap one left over????
I tore apart my boost gauge today. It's actually pretty easy and the rumors that there's some elaborate springs that fly out when you open it are complete bunk. What broke on the gauge is a tiny plasitc arm that joins the needle movement to the coil that's deflected by air pressure. It's a simple mechanical connector, bone shaped, that connects two metal arms by a little expansion fitting that goes through holes in the two arms. The fittings on the plastic piece look like the ones that clip the black body screws on the car. If I can find a way to secure the one arm to the other I'm in business. As far as cabibration goes, I don't see how that's accomplished at all.
Because I believe that piece is usually the one modified when calibrating a Bourdon tube pressure gauge. You shape it to achieve the gain you want (expensive gauges have an adjustable linkage there). Then you position the needle and/or pinion to get the correct bias.
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
Yep, that's the piece. I did manage to get it to go back into the hole and to be set at zero. I have doubts about it working though. I wish I could find somewhere to get that linkage piece.
I have an OEM WRX/STi boost gauge laying around that reads -.04 MPa at atmospheric pressure. I'm not sure what size gauge you are looking for but I believe the OEM is 1 3/4 in. in diameter. Didn't try breaking into the gauge myself but if you want, I will let this go for cheap. I also have pics, PM me if your interested.
I may have fixed it. The linkage slipped into the hole and I pissed around with it until the needle rested at zero. I have yet to put a known pressure into it but there's a flow control valve at work with a guage on it I'm going to try in a day or two.
I realize it seems I'm talking to myself but here goes anyway.
I just said screw it and bought a Phantom series gauge from Autometer. It works fine and I'm in the process of installing the FCD for anyone who might read this.
I'm gonna put my old one in the new box and take it back as a return. Just kidding, it wouldn't work anyway.
That really just pisses me off at me. It dropped out of the box onto the pavement on the way into the auto parts store, grrrr. Now I'm out fifty bucks and I don't want to shell out more right now for another one. Anyone got a cheap one left over???? 
I had to...