How does one calculate where your MAP must be at a certain Alt/Elevation during a max power take-off? For instance: we know that the manifold must be +-22MAP at an elevation of 5500amsl, but how do we KNOW that 22MAP is the golden number at 5500elev? How can I calculate what my MAP will be (for example) at an elevation of 8500' for take-off? I want to ignore the rule-of-thumb and rather use a graph of some sort! :-) Hope someone can help me!