Manifold Pressure/RPM Relation

[ual763]

Shouldn’t the Manifold Pressure increase when RPM is decreased with the Prop lever?

[mizra108]

It does, but only just slightly. During run-up, when cycling the prop for example, a drop in 500rpm would yield about an 1” rise in manifold. For lower rpm reductions of a couple hundred rpms at a time, you may see perhaps a 1/2” rise and for rpm adjustments of 100 or less, MP needle movement is even noticeable. @ual763