Prochargers N Boost..
 

Is it normal for Procharged engine to have less boost when it's warmer out ?

Was testing a prop yesterday, in the warmest weather I've run this engine in, (92°) and noticed I was down almost a pound of boost at 6000 RPM..

No signs of the belt slipping. Engine seemed to run strong. When I checked the fuel learn table, it had pulled almost 10% fuel out on the top end.
Checked the datalog and it made 9.1 LBS of boost at 6000 RPM where it normally makes a solid 10 Lbs...

SOO Close to triple digits.. :)



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Yes. Thats normal.

So, to hit 100 you need a cooler day or ask your passenger to jump.
Congrats, sounds like you are getting it dialed in and you will be at triple digits!

Padraig

Our mini Winnebago..
a Velocity 290sc..






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I could tell you how to make consistent boost but you may break that drive.

Let me throw out a couple of thoughts. You are reading the map sensor which reads the absolute KPA the intake is seeing. If the barometer changes, that number changes. You go up to high elevation and the kpa will read a lot lower and your data log would show a lot lower. However if you were looking at a boost gauge it would still read 10 psi boost, which is the amount of pressure above atmospheric you have. So, your data log will read something different every time, but it shouldn't be nearly as much as you are seeing. I also believe that with hotter, less dense air the boost will drop slightly, inlet air temp changes. Another thought, boost is created by load. If the load at a given rpm changes the boost will also change slightly. So weight, trim and water conditions can impact it, especially with a centrifugal as compared to a positive displacement supercharger.

Bob

Yes... Air Density or ADR , Aircraft stuff , higher numbers more lift . More Power
Lower number , less lift or less power.