Proper Fuel Flow for IO-360

[Jeev]

I am trying you get my FF dialed in on the new engine for max longevity.  I have read some places that 10% of rated HP is a good place to start.  I took the plane down to the Southern CA coast to get some baselines since the D/A here in Vegas is always 4000-5000 this time of year.  At sea level around 70df, full rich, full power (MAP 29in / RPM 2700) my max FF was 19GPH and EGT's were all around 1320df.  At sea level I like to see the EGT's in the 1250 range should I bump the FF up to 21-22gph?  What are you guys seeing for FF on your 200hp IO-360's?

Thank you,

Sanjeev

[Jeev]

Just now, bluehighwayflyer said:

I typically see around 19 gallons per hour here in Florida at sea level in my J and I'm led to believe that that is about right.

Jim

Thank you

[KSMooniac]

I concur...18-19 is in the right ballpark. Your EGT reading depends where the probes are located, ie how far down the tube from the cylinders.

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[Jeev]

2 minutes ago, KSMooniac said:

I concur...18-19 is in the right ballpark. Your EGT reading depends where the probes are located, ie how far down the tube from the cylinders.

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Cool thanks.  Yea I guess I am just seeing variation due to the new engine as the probes are located in the same spot since we reused the exhaust risers.  I know EGT's are more of a reference than an absolute but I'm just being too anal.  Thank you guys I'll leave the FF where it is. 

[jetdriven]

The fuel flow is not adjustable in the RSA-5 fuel injection units. 

[Jeev]

4 minutes ago, jetdriven said:

The fuel flow is not adjustable in the RSA-5 fuel injection units. 

Very good to know.  I learn something everyday on MS!

[jaylw314]

The highest FF I can get on takeoff is about 16.9 gph.  I've mentioned it to my A&P and he said the same thing, and that the only mixture adjustment is the idle mixture.  In any case, I never have problem CHT's on takeoff, so I figure things can't be too bad.

[Marauder]

Are we talking about any IO-360 or the variant found in the J? On my F I never see above 16. Normal EGT ranges and normal (if not slightly low) CHTs.


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[Jeev]

I was talking about the 200hp variant in my J

[Marauder]

I was talking about the 200hp variant in my J

I know the Js have an IO-360 AxXx variants. Mine is an IO-360 A1A, also at 200 HP and also with the RSA-5 fuel divider. Why would I be running 2 to 3 GPH lower at takeoff power?


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[Marauder]

What is your field elevation, Chris?  
Jim

436 feet


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[Shadrach]

23 minutes ago, Marauder said:

 

I know the Js have an IO-360 AxXx variants. Mine is an IO-360 A1A, also at 200 HP and also with the RSA-5 fuel divider. Why would I be running 2 to 3 GPH lower at takeoff power?


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All of the 200HP angle valves run 8.7 to 1 C/R and Bendix RSA-5.  What's good for one is good for all.  What are your EGTs on take off?  Mine are in the mid to high 1100s.  A good rule of thumb is max rated HP/10 for a standard day at sea level.  You should be seeing north of 20gph on a frosty Delaware morning.  Any chance that your totalizer isn't properly calibrated?  When was the last time the fuel servo was serviced?  Any trouble with CHTs on climb out?  I don't have a totalizer but I flight plan 19GPH for the climb and I lean for 1200 (+/- depending on CHTs ) all the way to altitude.

[ArtVandelay]

Are we talking about any IO-360 or the variant found in the J? On my F I never see above 16. Normal EGT ranges and normal (if not slightly low) CHTs.

I see the same as well with my J FWIW.

[ArtVandelay]

I don't have a totalizer but I flight plan 19GPH for the climb and I lean for 1200 (+/- depending on CHTs ) all the way to altitude.

What’s you peak EGTs?
Mine is ~1550, so I lean for 1400, or 150 ROP. CHTs peak around 365.

[Marauder]

All of the 200HP angle valves run 8.7 to 1 C/R and Bendix RSA-5.  What's good for one is good for all.  What are your EGTs on take off?  Mine are in the mid to high 1100s.  A good rule of thumb is max rated HP/10 for a standard day at sea level.  You should be seeing north of 20gph on a frosty Delaware morning.  Any chance that your totalizer isn't properly calibrated?  When was the last time the fuel servo was serviced?  Any trouble with CHTs on climb out?  I don't have a totalizer but I flight plan 19GPH for the climb and I lean for 1200 (+/- depending on CHTs ) all the way to altitude.

My CHTs are low. On a hot summer day climbing full power at Vy, I may see 360 to 370 on the hottest cylinder. EGTs as you know are subjective based on probe location. My EGTs are in the mid 1300s.

I pulled my JPI data last night and will have a look again, but ever since I installed these monitors with fuel flow capability, I have never seen high fuel flow rates.

Ever since I installed the CiES last Fall, I have been monitoring my actual fuel burn against the fuel totalizer and fuel quantity gauges. I have my fuel transducer dialed in. I am within 0.3 gallons of actual fuel used on 95%+ of all fill-ups. The only time I may be off is when there is a large temperature change.


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[Shiny moose]

.5 pounds per hp per hour. So your 200hp at sea level should burn 100 lbs per hour, with a weight of 6.02 pounds per gallon equals 16.6 GPH at full power

65% power setting on an IO360 200HP would be 130 HP using 65 pounds per hour or 10.7 GPH 

 

 

[Bob_Belville]

I flew yesterday. Data from TO roll: 1260' field elevation, 28.9" MAP, 2684 RPM, 91% power, 17.9 gph FF. 

That's typical for my IO360A1A and what I like to see, i.e. near 18 gph on take off.

(For what it's worth, Savvy's fairly ne report card calls my max ff "average".

MAXIMUM FUEL FLOW DURING FLIGHT

Measures maximum fuel flow during flight, most likely during takeoff. Sufficient fuel flow is important for proper cylinder cooling during high power operations

SAVVY SAYS...

Your maximum fuel flow is average when compared with your cohort. (Paul may have something to add but it appears my E is mixed in with the 180 hp models. If that is true, the O360 is averaging over 17 gph max ff. 

N943RW · M20 (A/B/C/D/E/G) · IO-360 · EDM-930

Includes 93 flights between Jan 01, 2015 and Jul 09, 2018, compared with 907 flights by a cohort of 40 M20 (A/B/C/D/E/G) aircraft.

 

[Guest]

From the Lycoming  360 series PoH.

 

[Marauder]

From the Lycoming  360 series PoH.
 

If my math is right, max fuel flow is ~15.8 GPH at 200 HP full rich.


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[jetdriven]

That chart says part throttle fuel consumption and its best power mixture. If you want full throttle full rich FF it’s a different chart 

Edited July 10, 2018 by jetdriven

[jaylw314]

5 minutes ago, jetdriven said:

That chart says part throttle fuel consumption and its best power mixture. If you want full throttle full rich FF it’s a different chart 

I haven't seen a chart for full rich FF.  15.8 gph sounds reasonable for best power, that means takeoff FF of 18 gph would be about 2 gph more.

Mine still tops out at 16.9 gph though.

[Guest]

11 minutes ago, jetdriven said:

That chart says part throttle fuel consumption and its best power mixture. If you want full throttle full rich FF it’s a different chart 

I noticed that as well, the POH doesn’t show one for full throttle.  It’s hard to imagine it makes full rated HP (200) at less than full throttle.

Clarence

[Shadrach]

6 hours ago, teejayevans said:

What’s you peak EGTs?
Mine is ~1550, so I lean for 1400, or 150 ROP. CHTs peak around 365.

#3 is the first to peak and highest, ~1525.  I like 250 ROP in climb, more if it’s really hot.

Edited July 10, 2018 by Shadrach

[Shadrach]

2 hours ago, M20Doc said:

I noticed that as well, the POH doesn’t show one for full throttle.  It’s hard to imagine it makes full rated HP (200) at less than full throttle.

Clarence

I think the northeast in February at my 700’agl drome the DA is sometimes in the -4000’ range.  Pretty sure it’ll make 200hp easily at partial throttle and and more than rated at WOT. Even on a standard day it’s rated at full power at full rich. It would be abusive, but if you leaned to best power at that setting it would make more power, so not a stretch to imagine full rated power at less than full throttle if leaned to best power.

. What’s odd about the chart is that it depicts thes abusive power settings. Leaning to best power at those settings is an obvious no no. 15.8GPH translates to 50ROP at 200hp and whatever MP is needed to support it. 

Edited July 10, 2018 by Shadrach

[Shadrach]

6 hours ago, Marauder said:

 

My CHTs are low. On a hot summer day climbing full power at Vy, I may see 360 to 370 on the hottest cylinder. EGTs as you know are subjective based on probe location. My EGTs are in the mid 1300s.

I pulled my JPI data last night and will have a look again, but ever since I installed these monitors with fuel flow capability, I have never seen high fuel flow rates.

Ever since I installed the CiES last Fall, I have been monitoring my actual fuel burn against the fuel totalizer and fuel quantity gauges. I have my fuel transducer dialed in. I am within 0.3 gallons of actual fuel used on 95%+ of all fill-ups. The only time I may be off is when there is a large temperature change.


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Timing set at 20 or 25BTDC?