When you're not putting load on your engine (boost), your gauge will be reading vacuum, measured in InHG or "Inches of Mercury".

Did you buy the gauge new? There is calibration paper work. There is a potentiometer on the back that you turn at key on engine off to dial it in. Glowshift is not the best, I installed a triple pod and couldn't get the boost gauge to zero out.

I contacted GlowShift tech support and after several emails they told me that I wouldn't be able to zero out my gauge because of my elevation which is around 5280ft here in the Denver area. So at key on I'm always -1.

You’re better off with a analog boost gauge.

Xarzor said:

Did you buy the gauge new? There is calibration paper work. There is a potentiometer on the back that you turn at key on engine off to dial it in. Glowshift is not the best, I installed a triple pod and couldn't get the boost gauge to zero out.

I contacted GlowShift tech support and after several emails they told me that I wouldn't be able to zero out my gauge because of my elevation which is around 5280ft here in the Denver area. So at key on I'm always -1.

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Yea I got it brand new I don’t recall looking at a paper that said the calibration but I’ll definitely look again hoping that’s what it is if not well I learned my lesson with glow shift gauges

I guess they have better analog gauges. I don't remember exactly, pull the gauge and turn the potentiometer on the back either clockwise or counterclockwise with key on and see if it zeros out. You will need a small flathead screw driver.

Besides that the gauge is fairly accurate accounting for vacuum being higher than it actually is.

Years ago I had a Glowshift gauge, it was 4 psi off from my map sensor, pretty typical of their quality.