Does anybody know how much boost you lose because your truck is running at 5000 feet?

 

It depends on how much you are trying to run. Not a smart A.. response, it's proportional. Here (5,000 ' plus) most folks got less than 8 pounds stock. Now I'm running an 8# lower, a 2.77" upper, a free flow filter/intake, on an Apten ported Eaton and see 16 #, 17 when it's cold. It's tough to get boost when you start with such thin air. The dynojet correction factor is usually 1.2, from acutal to SAE here, I've seen it higher. The majority of the correction is from the thin air at altitude.