I installed the Forge UNOS MBC today with the firm spring installed. Nice piece btw...now I did a search after the fact (installation) as to the best place to tap a vacuum source. I did this after the fact because I've really cranked down on the UNOS, perhaps 30+ turns and I'm hitting a quick 20psi which settles at 19 and tapers to 16-17psi on an Autometer boost gauge. UNOS uses the feed right off the compressor housing and the hose length is 10" at worst. So it's nice and close to the best boost signal. I started out +4 from full soft and have steadily cranked it towards positive throughout the day.

To get a signal for the boost gauge, I placed the Tee right at the manifold, specifically in the line that feeds the boost/vacuum signal to the BOV. I thought it was best to leave the signal going to the FPR alone (wisely as it turns out after searching) as I've never inhibited that line in any way/shape/form on any other car I've modified for fear of causing the fueling to go lean if a hose pops off, etc....

My concern with tapping into the BOV line is that if the BOV leaks (05 GSR), it may alter the signal to the boost gauge causing a low reading compared to actual manifold pressure. The car feels about right where the UNOS is set now although I'd like to get 21psi and hold at 19 or so without having to purchase the Forge actuator. What do you all think?

 

I locate all boost sensors together on a dedicated line from the manifold, and use a very short line. This way you are most accurately reading what's going on in the manifold.

BOV on a dedicated line as well. Ok...the theme here is " very short, dedicated lines" for best results.

 

I would still rather tap the FPR. It is a direct reading from the housing. Just ziptie both ends and the hoses will not come off.

 

I cut off a small piece of vacuum hose and slid that on the manifold vacuum-source nipple. I put the tee into that so there's maybe an inch of hose and then the tee. Very short! But I'm wondering if a BOV that develops a leak would cause an improper reading on the boost gauge if it's on the same line/signal.

I cranked up the UNOS a bit further and went too far. Wow, car hits hard at 25psi. I'm now having to take out quite a few clicks on the boost controller. Wondering if something wasn't moving freely inside or something.