T2 Map Gauge

[CrazyBob]

Ok lets see who is the smartest one out there,
This is a vacuum related issue.
At idle T2 Shows 4psi.
Mechanical gauge shows 16inhg.
Barometer is 25 psi or 12.03inhg
so here is the normall conversion
T2 showing 4 psi would be 8.1441 inhg of vacuum.
Mechanical gauge reading 16inhg so T2 should be showing 8psi if using standard conversion@32 degrees.
Whats the math to reconcile the difference? how does Baro enter the equation?
Thanks Guys!!!

[mikel]

Can you post a log?

[CrazyBob]

ok here is a log file i just made for you, numbers arent an exact match but close enough, so johan gave me the math to to take map info from t2 and calculate boost and ive modified a second map pid to show me actual boost ( wish there was one with t2 for the jeep) but i want to understand the math behind calculating true vacuum.
my mechanical gauge shows 16inhg of vacuum while the t2 shows 4psi manifold pressure, the standard inhg to psi and psi to inhg doesnt give correct values so there must be more math envolved , johan says baro info but he is hiding the formula from me lol
thanks
Crazybob

[mikel]

T2 has a synthesized PID under miscellaneous that shows boost (MAP-BARO)