Manifold Air Pressure questions

[Gyronaut]

To the clever people out there, please help me clarify something in my own mind.

I think I understand what Manifold Absolute Pressure gauges do.

What I don't understand is what purpose a MAP gauge has on a machine with a turbo charger, that has a fixed pitch prop and no mixture setting other than to possibly indicate a malfunction and an 'over-boost' which the Turbo Control Unit does in any event? As I understand it, in the aforementioned case, Engine RPM and MAP will correlate at any altitude and remain consistent.

So, the question is, on a 914 Rotax, fixed pitch, is there any reason for a MAP gauge?

... or am I missing something?

[MAGNIficent]

Jet Ranger,

See this post on Manifold pressure, I use it as my powersetting indicator, eg. 60%, 75% etc.

viewtopic.php?f=13&t=12748

[Gyronaut]

Thanks MAGNIficent

Great article. It specifically speaks about normally aspirated engines and does not really cover the scenario my questions were about.