Difference between Ambient pressure and MAP at full throttle

[Salty]

Assuming a naturally aspirated engine. What's a "normal" loss of pressure if the intake filter is clean and everything is working properly. It's obviously going to be "a little" lower than ambient, but I can't seem to find anything on what is a typical "good" number.

My IO-540 seems to be about .9" lower. I have no idea if that's good or bad.

My Savvy report says I'm running higher than my cohorts but being I tend to operate near sea level, I'm not sure that means anything useful

 

[Bell206]

What's a "normal" loss of pressure if the intake filter is clean and everything is working properly. It's obviously going to be "a little" lower than ambient, but I can't seem to find anything on what is a typical "good" number.

I can't find the reference, but I believe at sea level on the ground with the engine running the MAP should be approx. 2 inches below ambient due to the interference/friction of the induction system. In flight, with ram air it should be around 1 inch below ambient. There was an old Lycoming (or TCM?) Bulletin that explained MAP and its comparison to ambient pressure but can't place my finger on it at the moment.

 

[GeorgeC]

I fell down this rabbit hole a little while back...

how to read "sea level performance curves" charts

I'd been having a hard time interpreting charts like the one I have attached. The glossary defines "propeller load curve" as "a plot of horsepower, fuel flow, or manifold pressure versus RPM through the full power range of one engine using a fixed pitch propeller or a constant speed propeller...

www.pilotsofamerica.com