Fuel flow takeoff power

[8 ball]

I have an o-320 that has 9.37:1 cr. (measured). It turns a metal Senchenich 72x75 2280 shortly after takeoff. Fuel flow is 11.5 gph. How does this sound? Lean? On hot Texas days I have to keep it
above 140 mph up to about 4000 ft. to keep cht's. below 425 f. The baffeling is very tight (all holes and cracks filled). It has the air exit ramp between the dual exhaust.
RV 8. 1155 lbs

[bobbyhargrave]

I see 19 gph on takeoff and climb at full throttle and 2700 rpm. O-360-A1A, Hartzell c/s, Marvel M5 carb., 120kias climb speed with no CHT exceedance.
Sounds lean to me.

[N941WR]

Check the Lycoming operating manual for your O-320. Your numbers sound about right but I really don't know for sure.

The (I)O-360 can drink some fuel. When I was breaking in my O-360 I was planning on between 16 and 17 GPH at full throttle and full rich.

[n82rb]

The lycoming chart showed about .58lbs/bph/hr that's about 15 gal/hr full rich,full power, standard sea level day.l

Bob burns n82rb rv-4

[8 ball]

Thanks folks, anyone have experience with jet size? Just open it up a few thousandths?

[rv7charlie]

Originally Posted by n82rb

The lycoming chart showed about .58lbs/bph/hr that's about 15 gal/hr full rich,full power, standard sea level day.l

Bob burns n82rb rv-4

Time out; he's got a fixed pitch prop. .58-.60 is likely a good number range, but you need to find power at his actual takeoff rpm (2200) & full throttle, not full power (2700rpm).

I see around 13-14 gph with an O-320/160 hp. I'm suspicious that it runs a bit richer than Lyc spec at full throttle.

What does the chart say at sea level MAP & 2200rpm?

Charlie

[Beancounter]

8 Ball
I have 9:1 comp o-320, 72" fixed pitch sensenich prop combination and get very similar RPM's after take off. I see 11.1 gph at that RPM. Not saying that this is good just a data point.

From the Lycoming chart I calculate aprox 110hp at 2300 rpm or 69% of 160 rated power. Using .6 BFSC x 110hp = 66 lbs/hr or 11gph. If I am reading the chart correctly at 2300 rpm and between 24-28"mp the flow is 9.5-12gph.

[swisseagle]

I see at full power on ground this:

IO-320 / 160HP
Sensenich metall FP
2200 RPM
79% Power
12.2 GPH

Hope it helps!

[8 ball]

Bean counter sounds like a fairly close comparison.
I am definitely in the 9 to12 range. I have had the timimg all over between 20 to 30 degrees. 20 helps some but costs over 50 rpm at altitude.
Thanks for all the help fellows.

[Sam Buchanan]

Originally Posted by 8 ball

I have an o-320 that has 9.37:1 cr. (measured). It turns a metal Senchenich 72x75 2280 shortly after takeoff. Fuel flow is 11.5 gph. How does this sound? Lean? On hot Texas days I have to keep it
above 140 mph up to about 4000 ft. to keep cht's. below 425 f. The baffeling is very tight (all holes and cracks filled). It has the air exit ramp between the dual exhaust.
RV 8. 1155 lbs

Those are about the same numbers (rpm and flow) that I see with my RV-6 (O-320, Sensenich 70x80).