Manifold Air Pressure (M.A.P)
What Is M.A.P ?
Manifold Air Pressure is the air pressure in the inlet manifold of a piston engine.
It can be used as an indicator of engine power output.
This is an M.A.P gauge from a Schweizer 269C1.
Manifold air pressure gauges are normally calibrated in 'inches of mercury' (in. hg) which is one way of describing a pressure.
Atmospheric pressure is appproximately 29.92 in. hg at Sea Level, reducing at a rate of 1 inch per 1000 ft of ascent..
AvWeb Article on MAP
Rod Machado Article on MAP