[quote=motoworkz]Not trying to diss on you or anything but I don't under stand what PR is. I think you mean BAR. Please clarify.
PR = Pressure Ratio
1.0 PR = Ambient air pressure ~ 14.7 PSIa at sea level or 0 PSIg
2.0 PR = 2 atmospheres of air pressure ~ 29+ PSIa or ~15 PSIg
PSIa is absolute air pressure (0 = vacuum)
PSIg is gauge air pressure (0 = 14.7 PSIa) or boost
But if you're in Denver @ 5000 ft. The ambient air pressure might be 12.2 PSIa, and at a PR of 2.0, your turbo would be pumping ot 12.2 X 2 = 24.4 PSIa or 24.4 - 12.2 (0 point on boost gauge) = 12.2 PSIg of boost instead of the 14.7 PSIg you would have seen at sea level. (This is only acurate if the turbo was not being regulated by the waste gate or the blow off valve at this load)