putting check valves in between map seems preety easy to me

 

richen the last column... wait a sec, just buy a 2.5 bar map for 18 bucks and be done the right way

 

4 check valves (from pet store, for fish tank) inline between the vacuum source and the map sensor, you want to bleed the boost air from the map sensor so it doesnt throw a cel. Also put a check valve on the line that goes to the charcoal canister to prevent it fron seeing boost.

Cheers