GM.MANVAC vs. SAE.MAP

[Lennart]

I noticed that the IFR is based off of GM.MANVAC. In the past I only logged SAE.MAP. What is the difference between the two?

[SSpdDmon]

Baro minus MAP = Manifold Vacuum

So, if you live close to sea level where Baro is ~100kPa and you see 98kPa at WOT, then Man. Vac. is 2kPa.