Boost differences at different altitudes ??

[never enough]

I was wondering if altitude makes a difference in boost ? Only reason I ask is i have a 5 psi pulley on now and I get 3to4 psi boost with a 6 inch crank pulley. Could altitude make this difference? I know the unit will boost more because I had a 3 inch pulley that the unit came with and it boosted over 7psi at 3000rpm. any help is appreciated...Als

[bumblebee03]

Yes.. Higher altitudes will decrease your boost,,, I lost about 3 lbs of boost moving up to 5800ft,,, I put on pulleys to give me 14lbs and I am seeing about 10 when the belt is gripping good,,, Bee