The newer MEFI ECM's have an input for a MAP and a BARO (senses ambient air pressure) sensor. Anyone have any experience with including a baro sensor in a speed density tune? Typically ECM's read baro at start up for a reference to start from the MAP (MAP = ambient before start), then MAP to calculate air density after start....would an additional baro input be that much better?"

 

Sure, when you live in the mountains, if you start your car up on the hill (lower than usual BARO), then drive down the mountains, then the ECU will still work on that lower BARO assumption, until you restart the car.

 

Yes, but as altitude increases, so will MAP pressure, and somewhat compensate. Question is, newer ECM's like the MEFI 6 have capacity to read BARO as well as MAP; will this greatly increase the tuning with changes in altitude?