You're right. I should have raised the power before multiplying by 80. That still gives me a PSI that is way out of whack.
1250 divided by 3305 = .3782
.3782 to the power 1.25 = .2966
.2966 x 80 = 23.72
My door jamb says 32 PSI. Using JB's easy method, I get 42 - 47 PSI, which is right in line...
