air viscosity being less dense at higher altitudes on would think that boost could be increased to obtain more horsepower since pressure inside the cylanders woulld be less than the equivelant boost at a lower altitude. is this true? I was just thinking since I am at about 5400 feet it would be safe to run a higher boost setting since the motor is working with thinner air. air fuel ration being in a safe range of course. just wondering. any experts out there know the skinny on this?

 

hmm, where you at? i'm from colorado (5000+ ft) and i have Saleen blower with JDM 8psi pulley. I'm actually getting around 7 psi in this altitude, but it works like a dream and hauls ***. I'm running JDM tune which feels spot on... I just received latest update and will dyno tune it soon. My boost gauge is actually ½ psi on vacuum side when my car's off.

Anyway, PCM adjusts to altitude. Even with custom tune and SC. The way PCM adjusts AFR is leaning and richening the mixture constantly for stoich. There's no worries running boost in high alt.

 

You lose typically 1-3#'s of boost from sea level to 5000'. Your Stang will make about 70-80 less horses up at 5000' elevation as compared to sea level. So, if a 10# 05-07GT makes 475-480rwhp at sea level, it would make about 395-400rwhp at your elevation. So, you could pulley down and add 2-3#s of boost and shoot for about 425-430rwhp at your elevation and still be considered safe in theory. But the question is up in the air, as to whether excessive boost kills the stock crap rods/pistons. Or excessive horsepower? Keep in mind if you ever were to take the Stang down to sea level, the car would pick up sick horsepower and run dangerously.