Question for those running a P3 Gauge on their Supercharged Car

[Deebo]

I know the most common method for reading boost is to tap into the vacuum line off the BOV with a T-fitting. The question is- where the hell do you find a T-fitting that reduces down to the tiny 5/32” OD hose that the gauge reads from? I bought mine used, did everyone else purchase the tubing kit with the fitting directly from P3? Any insight you have would be great, I’m running a 1/8” vacuum line and after hours of searching can’t find a T-fitting that reduces down to 5/32”.

[amrazM]

s65b40 doesnt create positive pressure on the line coming off the vent valve so you may not be able to T off the bov line. you need a source coming off the plenum in order to get vacuum and boost reading.

[Iyzmi]

Originally Posted by amrazM

s65b40 doesnt create positive pressure on the line coming off the vent valve so you may not be able to T off the bov line. you need a source coming off the plenum in order to get vacuum and boost reading.

Mine is T'ed off the BPV line and reads both boost and vacuum, I believe this is the most common configuration people run. If you tap the manifold you will only see boost and not vacuum.

[amrazM]

Originally Posted by Iyzmi

Mine is T'ed off the BPV line and reads both boost and vacuum, I believe this is the most common configuration people run. If you tap the manifold you will only see boost and not vacuum.

Where is that line to the BOV coming off of? I have my line coming off the loop at the idle control valve and it reads vacuum only.

[Iyzmi]

Originally Posted by amrazM

Where is that line to the BOV coming off of? I have my line coming off the loop at the idle control valve and it reads vacuum only.

It comes off the fuel tank breather valve, like this:

[gilberjj]

I’m having my car shipped to me and I’ll take a look once it arrives. Until then I’ve got a question. I just bought a 2011 e92 with a G-Power SKII supercharger kit. It has the p3 gauge. I noticed that at wot, the throttle only goes to 74%. Is my tune screwed up, or is this just a quirk of the p3 gauge?

[Iyzmi]

Originally Posted by amrazM

Where is that line to the BOV coming off of? I have my line coming off the loop at the idle control valve and it reads vacuum only.

Originally Posted by Iyzmi

It comes off the fuel tank breather valve, like this:

Is this not how yours is set up? No reason for you to not see a boost reading if you have everything hooked up correctly and T off the BPV.