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Looking for some representative idle Fuel Flow Numbers

steve murray

Well Known Member
Hopefully I am few weeks away from first flight and ticking off final punch list items.

I want to get ballpark calibration of my fuel flow indicator which is counting fuel injector pulses vs mechanical system.

Can someone with IO540 8.5 pistons give me your full rich idle 1000 or 1200 RPM fuel flow numbers, I will use this as ballpark start for my first flight. I checked the Lycoming data sheets but they do not go this low.

Thx

Steve
 
With IO-540 D4A5 AFP FM-150 :

OAT 8, Density Altitude -200
MAP 15.5", RPM 1000

I see 5.8-6 GPH, full rich

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OAT 29.4, Density Altitude 2758
MAP 16.8", RPM 1000

I see 4.9-5.1 GPH, full rich
 
I have 8.5:1 pistons and I adjusted my idle mixture for 1.5 to 2.5 at idle depending on actual rpm and mixture setting.
 
I?ve found that engine temps really play a role in my idle fuel flows.

On a cold engine, I can see 6.x gph. As the engine warms those number drop significantly. By the time I taxi out they might drop down to the 4?s. After I fly it and taxi back in on a hot engine, it will be down around 2.

If yours is like mine, a hot engine will idle much less fuel than a cold or warm engine.
 
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