Are you meaning the 2psi above 14.5psi? I think that is the margin of error because i dont think any sensor is exactly at 1bar or 2bar or 3bar. Most can read slightly past but it just wont be guaranteed as accurate as you would be if you stay within the suggested range of operation.

 

no - I mean what is the MAP sensors purpose on the Evo - given that we have a MAF

 

Mainly EGR check.

 

Which would explain why the same load at different rpm can mean different amounts of boost. The above calculation would then need to take rpm into effect to accurately predict boost.