Ok this will probably sound like a dumb question: my analog boost gauge reads 9or10 psi but the vipec is reading 130ish kpa. I thought 130ish kpa is around 4-5psi. Why the difference? This is riding at 9,000 ft elevation. I'm assuming this has to do with elevation, is there an equation for this?
Also the Vipec is giving you absolute pressure, so subtract atmospheric pressure for your elevation, 72kpa, to give you gauge pressure or boost pressure130 kpa is just under 19 PSI. Assuming your at altitude your boost gauge is correct.
To convert KPA to PSI multiply the kpa value by .145
(130kpa-72kpa)*.145=8.41 PSI as indicated on your gauge