IO 360 M1B FF at T/O full power
 

I am trying to find what is the anticipated fuel flow (or range) for an IO 360 M1B (Van's) with C/S hartzell and Precision FI. Full throttle / full rich during take off and initial climb near sea level. I have done a search, and although this bush has been beaten around several times, since I am trying to solve an unusual problem, I need info only pertaining to this engine/prop setup, of which there should be many I suspect.
No response from Lycoming and this bit of information is not in the Manual. Waiting for response from Van's. Response from Precision Airmotive was quick and informative, but they do not know the fuel flow intended by the engine manufacturer since different installations may not achieve different fuel flows.

I will post any data I recieve to assist others.

Thanks

You should usually see .9-1.0 gph per 10 hp. I know this is not specific to your engine, but with no other replies, I figured I would at least give you some answer.

With this engine & prop combo I run about 16gph at sea level 2700rpm full throttle FWIW.
Cheers

Hum...I've heard one Lb. Per HP per Hr? Not sure........

That would mean a 180hp engine would be burning 30 gph at takeoff. Our RV-10 with 250hp burns 23-25 gph at takeoff at sea level.. Another -10 I flew today was reading 22.5. The other comment of 16gph, I assume with a 180hp engine.

Taking off, I'm burning between 15 and 16 gph. As soon as I'm at altitude, I slow it down a bit and settle to about 7.2 to 8 gph cruise.

The data sheets with my (180hp) IO360 M1B engine shows 87 pounds per hour or 14.7 GPH at WOT 2700RPM and best power A/F.

The sheet for the 200 hp shows 93PPH or 15.5 GPH.

A little variation or additional richness (is that a real word) then You have an operational range.

This makes BSFC .465 to .485 #/hp-hr.

Your data may vary. (YDMV)

From my datalogs, I typically get 17.2-17.7 gph on take-off. Superior 180HP IO-360 with P/A injection, Hartzell blended airfoil prop. My prop overspeeds a bit on take-off, something I need to deal with. Typically I'm at 2730 rpm on the roll.

I get about 15-16 gph at the full power with the same engine/prop. Hope this helps

TO FUEL FLOW
 

G'day,

Same engine, injection, & prop, RV-7: 61.5 litres per hour (16.2 USG/Hr) PA 70ft AMSL, DA 2000ft.

Regards,

Gents,

This is one area Lycoming normally do far better than TCM, correct fuel flow at full power full rich.

The correct answer is just a tad under 18 GPH, something around 17.8 USG/hr at ISA and sea level. You can have a bit of latitude, but under 17.5 at ISA would be sub-optimal.

BillL, your data is for around 75-100dF ROP, I suggest that is a very wrong takeoff fuel flow. If you would like, go try it and you will see why.

Jesse, at ISA conditions you should see around 24.5-25 GPH and typically you are in the ball park, whoever has 22.5 assuming sea level 1013 (29.92) and 15dC is in a bad karma zone.

Hey Rags, if you reverse engineer your numbers for the 2000' DA thats about 17.5, so on the money. ;)


Airhead, why are you anticipating? Just for first flight information? If so that is assuming the K factor is set right. But a good idea to be watching for it.

I am not sure why but anyone with an AVSTAR FCU might want to check theirs, I have seen a few far too low.

Bob,
Your Lycoming Operating and Installation Manual IO-360...series should have a Fuel Flow Versus Power chart for your "uninstalled engine." My chart was accurate within 0.5 gph at full power sea level. A fellow builder with a 0-320 observed the same accuracy.

Since I live at sea level and can fly at near standard day conditions it was fairly simple to validate Lycomings numbers. The green run sheet showed a 1.0 gph correlation. As an aside my IO-390 burns 18.5 @ 100% power.

I am seeing 25 gph, 1250F EGT's or about 200F ROP. I keep CHT's under 380F on climbout.

.55-.60 Lbs/hr per HP.

18 or less
 

Jesse had it in the second post. 10% of rated HP is really close. Thats at sea level with standard atmospheric pressure.

Eddy

This post exhibits exactly why I am trying to be specific with my question of fuel flow at full power T/O. Two of the reply's (Paul K & Mehrdad, which I think are both IO 360 M1B Precision FI, C/S prop) are recording fuel flows in the 15 to 16 gph which is what I am experiencing. (I assume Paul and Mehrdad are happy with their numbers). All others are (recording or predicting from charts) higher flows. That is the same spread I have seen in other posts about this subject.

Reason for my investigation: I currently have about 50 hrs on my 7A. At about 20 hours my FF @ T/O full power, started dropping over a period of couple of hours flight time from 18 to closer to 15+. The engine still develops same rpm (2680), is smooth and otherwise performing fine. What brought this to my attention was that I noticed the CHT's were rising to the 430-440 (before reducing power to cruise/climb) range instead of the 400-410 I was recording prior to the mysterious drop in FF (I have the Skyview EMS with red cube FF transducer). This despite the fact that the first 20 hours were in August. I can't see any other engine parameters that have changed. I have checked the mixture control and am getting stop to stop movement. Also checked torque on servo to engine and intake manifolds. The CHT rise (only peaks to over 400 for about 1 minute typically). I can live with that if necessary by adjusting my climb speed and timing for power reductions. But because of the shift in FF over a relatively short period of time I am being cautious, and exploring any possibility. Precision Airmotive has been responsive, and said they will be glad to inspect the servo and adjust if necessary at no cost. But before I go to that time and trouble I wanted to see what others with same installation are experiencing. By the way, I am very happy with the PA system which is giving me a CHT spread of less than 20 degrees and a EGT spread of less than 40 degrees. No GAMI's in my plans.

opps. I was thinkin of the twin big block boat set up....actualy a rough etimate for sea level normaly asp - 1/2 pound of fuel per HP per HR.

I just got a reply from Joe at Van's. He is referencing charts and graphs in Lycoming (or Lyc clones) manuals and interprets 14 to 16 gph. However, my manual has the same charts, and these (the way I interpret them) are for cruise, i.e. "Best Power or Best Economy" settings, not necessarily for full power / full rich WOT T/O conditions where you might want slightly higer flows for cooling. Having said that, the M1B engine seems to be very fuel efficient. I have flight tests recording cruise flows of 8.0/8.5/9.0 GPH at 65/70/75 percent power respectively (peak EGT at 8500 PALT) which is at the very low end of the various charts I have seen. Which is another reason for asking for data from owners of same engine/prop configuration.

I have been meticulously recording (and charting) my fuel tank levels (both stick and guage) and fuel additions after every flight in order to calibrate K value. I have very gradually adjusted it from 68,000 initial (recommended by Dynon) to 74,000 current.

My friend's RV-8 with ECI Titan IO-360 (very similar to IO-360-M1B but has 9.2:1 compression, cold air induction, ~192 hp, etc) and Hartzell BA prop runs around 18-19gph at full takeoff / full rich power. So Jesse's formula is right on for this engine.

My reading on my Dynon's and on the GAMI report I sent in shows 16.1 GPH
at takeoff 2690 RPM MP varies according to alt. 1520 elevation. 45 degrees.

IO360MIB Hartzel blended airfoil prop. Horizontal intake.
Jack

I appreciate all the replies.

Questions if you tune back in to this channel:

1. Do you have Precision Air FI?
2. Do you know your K value setting for your EMS fuel flow monitor?

So far Based on replies, M1B's are indicating significantly less FF at full rich WOT T/O conditions than other 180 hp 360's, ie; 15 to 16 rather than 18+.

That is correct for my case (Precision Air FI) and and although I don't another engine/experince to compare it with, I do believe I develop full power and reach the max RPM set in a very short distance on the go. I tested this mainly to see what is the minimum FP I need in order to run at full power and if memory serves me right, that was about 17 PSI. Of course my normoal FP is about 27 PSI and with the boost pump on, it goes to 33 for a short duration and comes back to the 27 PSI.

I can look up my K value next time I am going to the hanger.

Bob, I would hate to sound like I am harping on, but the correct answer is detailed in my post above. You have just explained a lot more detail that should have been in the opening post, although some EGT data would help.

Now I read that you have been over time adjusting your K factor. Could it be that this is really your problem? But that does not explain the high CHT's which is a classic sign of trouble.

The PA system is good and you should be happy, provided it is correct. The 20d CHT spread is good, but that is not attributable to PA, the EGT spread (whoever thought that one up??) is irrelevant, but what would be more useful is the actual raw data EGT numbers as you pass through 500'AMSL at full rich, and the distance the probe is from the head. Could you please advise this.

I suspect that your FF problem is the K factor is now so far out of accuracy, or and this is a possibility, the mixture arm may well be on the FR stop in the hangar but when you take off the thrust pulls the engine forward on the engine mounts, the cable might be unable to take the movement without flexing the cable bracket and it is actually pulling the mixture back.

If you can close a few of these gaps I can hopefully point you in the right direction. Be careful of others saying things that sound right to you and your problem, and then assuming your all OK. Confirmation Bias is a dangerous thing. ;)

I get 16.9 GPH on takeoff at 2670 RPM with Mattituck TMX IO360 Precision FI, 9:1 pistons, horizontal induction.

Welcome to Internet forums, where no matter what specific question you ask, half the responses will be answers *about something else*, just like here :).

So, here you go with an answer to the actual question:

I have a Lycoming IO-360-M1B, Hartzell BA prop, and Precision Airmotive FI system. From the downloaded data, I see between 15.3 and 15.9 (probably depends on atmospheric pressure to some extent), at 2650 RPM WOT.

This is consistent with the Lycoming Operator's Guide, p. 3-21, Rev. Mar 2009, which shows 87 pounds/hr at 2700 RPM Best Power, making 180 HP (887 PPH = 14.47 GPH), if a little bit higher.

I'm at 1000 MSL at my home field.

Hope this helps.

My buddy's RV-8 has the ECI constant-return-flow type of fuel injection system. It's tuned to run a bit on the rich side at full power/full rich to help add a bit more detonation margin for the high compression pistons, and was done that way on purpose. It seems to be a good setup, since after almost 400 hours, the latest borescope inspection shows the piston heads and exhaust valves to be in great condition.

I don't remember what the K value was for the fuel flow transducer, but it's whatever was on the paper tag that came from Dynon. The RV-8 has a D-120 EMS and by measuring how much fuel gets added during each fill-up, the fuel burned measurements always seem to be within a gallon or so compared to what the D-120 says, so it's accurate enough.

Well you just said it..........:D
The Lycoming data to which you refer is a BSFC of 0.48, that is a long way from the normal full rich of around 0.57 - 0.58. So you have just added more misinformation to the OP's question.

The setting you refer is 75-100dF ROP, and I am sure you did not want that fuel flow for him or yourself at takeoff.

An off the top of my head calculation for you at 1000' AMSL with ISA day conditions is going to be around 17GPH.

Well, that's the ONLY chart that I could find in the Lycoming manual for the IO-360-M1B which gives fuel flow. I see the indication of Best Power on the upper set of curves, but I see nothing that says what dF ROP that's at.

Where do you see BSFC 0.57 for this engine in the manuals? I'm not saying it's not there, I'm just saying that I don't see it.

Also, my values appear consistent with the data from Lycoming's engine run-in tests.

(My comment about answers to other questions was about responses for engine/prop/FI systems *other* than what the OP had, which is what he asked...he doesn't have a 540, he doesn't have a Superior, he doesn't have ECI, he doesn't have an Airflow Perf FI, he doesn't have an -A1A or whatever...he has a Lycoming IO-360-M1B with a Hartzell BA prop and PA FI. Which is exactly what I have, so I gave him the manual page number applicable, and my data).

So let's see:

Responses *for that exact configuration* are:
16 gph (Richard Connell)
15-16 gph (Bavafa, but doesn't specify FI system)
16.2 (Bob Redmond)
EDITED (missed one) 16.1 (Smilin' Jack)
15.3-16 (mine)

and one unknown at 16 (Paul K) which might be the same combo.

Those all seem pretty consistent to me...

Since the chart indicates, as I said, 14.4 for rated power, albeit as you mentioned that's for Best Power, then 15-16 is at least 7% higher, as much as much 14%. Why would you say I (and the others here with similar numbers) wouldn't find that acceptable?

Oh, one other thing...when I said "consistent" with the engine test cell data...there's no FF at rated power given on the test cell sheet, only at AF-1000 (it's 82.62 PPH, which is 13.77 gph). I don't know what 1000 computes to in terms of percent of rated power or whatever. There's a thread on this somewhere I'm sure. :)

In any case, 15.3-16 has been flawless for my engine for 170 hours so far... :)

What do you think all the variances are about?

The fuel flow on take off at sea level or at 5000'AMSL is vastly different when using a PA fuel control unit. The variations being given are not even close to being accurately comparable. They all need to be referenced to sea level ISA day.

For example Bob Redman's data is from well above sea level.

The chart you are referring to where it states BEST POWER is nowhere near the fuel flow at takeoff full rich. Best power is around 75dF ROP, always!.

If your Density Altitude is higher than 0' then there will be less mass air flow through the FCU to the engine, thus the FCU will deliver less fuel and it does a pretty good job of being liner about it.

The simple way to tell is going through 500' AMSL you should get 1250-1300dF EGT or there about on each cylinder. But with the following stipulations. WOT/2700/Full rich, sea level & ISA day, static mag timing at 25dBTDC, 8.5:1 CR engine, all plugs in good order, no induction leaks, even half reasonable F/A ratio's (i.e.less than perfect GAMI spread).

Vary any of the above, the data changes. The simple answer is do the BSFC calculation, or the rule of thumb which is HP/10, or HP/10 less 2%.

If you have a low compression engine, the EGT will be about 100dF higher than above, and lets not contemplate TC/TN engines as they are not generally applicable in RV's.

The bottom line here is the charts you are looking at are not likely to have what you are trying to find, and I doubt they quote any BSFC at all. Regardless the laws of physics apply equally to all men, so no matter what FI system (or carb) the fuel flow numbers should be the same plus or minus some natural variations.

If you would provide details to all the variables I mentioned above I can do a back of beer coaster check on whether you really do have a conforming engine or not.

Last of all because I know Bob Redmans aircraft, my comment in post #11 is a clue as to what I am trying to help you (and others understand)
Hope that helps. :)

[quote=RV7A Flyer;844270]15-16 gph (Bavafa, but doesn't specify FI )/QUOTE]

Airflow Preformance.
IO-360-MIB
Hartzell blended airfoil
Density altitude - unknown

Now this is getting interesting. I personally have learned a lot during this investigation into my (possible) problem, both from data contained herein (albeit with a little drift as normal), and from further reading.

I think so far I have some very useful data from this post, as well as good points concerning comparision of data taken at different atmospheric conditions. Therefore, a range in flows should be expected, even with identical engine/prop/FI setups. However, I still think we are seeing that the M1B/Hartzell CS/PA FI gives a range of FF somewhat on the low side of the overall responses (but please keep the data coming in, particularly for this specific setup) and that my FF is not abnormally low. That is half of the answer I was trying to get by making this post, the other half being is this FF (15-16 gph at full power T/O) )so low as to be detrimental to engine life or performance? That is obviously only answerable by each individual owner , but I don't believe the complete answer lies in the Lycoming manual.

One test I have not yet performed that has been mentioned here and in most writings about this subject (and specifically mentioned in my discussions with Precision Airmotive as the definitive test as to whether my FI is delivering low flow during full power) is leaning from full rich to peak EGT at full power setting. I should see about at least 100 to 200 degree increase (hopefully at least 150, and no, I will not try this during T/O ). Will report back on this.

Response to Davd Brown's comments;
Well taken concerning engine thrust movement possibly affecting cable/arm movement. Was going to check this possibility.

My probes are all at 2 inches from head, and the spread I refer to is min and max between the 4 cylinders, ie, that (as I understand it) would indicate I am getting fairly even fuel distribution to the cylinders, and the reason I think credit is due PA is because the spider & injector nozzles are supplied as part of their system. The EGT at full power T/O is 1320-1330 (hotest cyl) at about 500 ft. (my airport is at EL. 40) At altitude (have not yet performed low level leaning tests as mentioned above) I see 1430 peak at 60 to 75 % power setting.

My K value has been adjusted only in small increments, and I did see a small drop in indicated FF as would be expected. I have kept a full accounting of my fuel burned and added since initial fill up at hour 1. I only made small incremental K adjusments (3 so far) at the point when the Dynon EMS (running total) fuel consumption exceeded my actual (carefully measured) consumption by a total of 2-3 gal (initially about 10 to 12 hours hobbs). However, I will continue to track this.

I went back and looked at my downloaded data (using Savvy Analysis) and noticed that although my airport is near sea level, since Florida temps are typically so far above normal, I have not yet flown at a DA of less than 500 and most flights started at 1000-2000' DA.

Bob,

Also consider the fuel density varies in batch and temperature. I just looked at density and with temp it is .16%/DegC. This may affect variance and may explain why the factory setting would be richer than "best power" as listed on charts. Another reason for higher than dyno stabilized FF would be that the engine is not fully up to temp on TO and will pump more air (and thus fuel) than a thermally stabilized engine.

None of this gives a definitive number for fuel flow, but may help (at least me) understand why real TO it is set different than the "best performance" nominal published for the engine.

Regarding your fuel flow decrease, you didn't happen to go through the fuel flow path and snug up the fittings after the first flights did you? Just wondering if the FF drop is real.

Good thread, this information will be helpful when I fly as your configuration is like mine.

I presume you meant 5000', not 500'?

(EDITED: correction...I think you meant 500' AGL, not MSL, in which case your statement makes more sense...but my situation is unchanged, as below...essentially no change in measured values in the 1st 500' of takeoff...I'm there before turning crosswind :) )

I don't know about WOT/2700 at 5000' because I never do that. But looking at my data, at 1000', WOT/2700/full rich (I've never seen an ISA day :), so we'll have to fudge that), 25 BTDC, 8.5:1, plugs just cleaned and gapped at annual, no leaks, GAMI spreads 0.1 or thereabouts, I get EGTs of (hey, guess what?) 1250-1280 (but I thought exact values of EGTs didn't matter because placement could affect the reading????). I also have CHTs < 400 (or just a tad above 400 on hot summer days, easily fixed by lowering the nose). Most recent flight had 15.5 gph.

So I've got values that seem to match the other 5 with the same engine/prop combo, are in line with whatever info we can glean from Lycoming, meet your EGT criteria, keep the cylinders reasonably cool and below 400...what's wrong here? What would upping the FF rate at full rich do "better"?

And...this is how the thing came from the factory, so is Lycoming all wet on how to set up their engines?

And...what would I do about it, anyway? I'm not going to tear apart my FI servo, I get good (28 psi engine-driven pump only, > 30 psi w/ boost pump) fuel pressure, mixture control is on the mechanical stop on the servo...what else would I do? Change the injectors to ones with bigger ports? I'm serious...I don't know what I'd change if what I have is wrong.

Two other things (sorry for the lengthy post with multiple questions)...I see "FF should be HP/10". Hmmmm...sounds like a "magic number" to me (and everyone admits it's just a rule of thumb). HP is an artificial number, not tied to any fundamental constants. 10 is, as always, a nice, round number, easy to remember, but again, arbitrary. So I'm not accepting that HP/10 is anything other than what a lot of people like.

And...help me out here...why do you say "normal full rich of around 0.57 - 0.58"? That may be correct, but why? Is it to avoid the "red cube" or red square or whatever people are calling it?

This would all be moot if Lycoming would just publish what the FF value should be...

I don't understand this statement. The chart has a curve for "Best Power" at 2700 RPM. Where that line intersects 180 HP, the value of "Fuel Consumption Pounds/Hour" is approximately 87 (app 14.5 gph). If best power is 75 deg F ROP, and this chart shows you what the fuel flow for best power is, then that fuel flow is 75 deg F ROP, right?

So > 14.5 gph is *even richer* than 75 deg F ROP. There are only so many variables to play with in these charts...HP? 180, check. RPM? 2700, check. Best Power curve is being used? Check.

That's it...then you read off 87 PPH on the ordinate. Thus, 87 PPH *is* 75 ROP if what you're saying is correct.

> 87 PPH is richer still. How rich is required is the question, and why.

Bob, now you are in the learning and discovery process.

By your get data alone the values seem a little higher than I expected, perhaps your FCU is on the edge of acceptable. Perhaps your mag timing is slightly retarded.

Gotta run to the airport....back soon for RV7flyer

Acknowledged in my case- But there are more similarities than differences.

The most significant difference in my engine compared to the Lycoming IO-360 M1B is the vertical draft sump. The M1B should actually make a little more power (and thus flow a little more fuel at WOT) than mine, due to the intake air not being preheated by the hot oil in the sump. Like the Lycoming, mine has parallel valve cylinders with 8.5:1 pistons and Precision Airmotive injection. Like the OP observed for the first 20 hours, I've always gotten close to 18 gph, full rich, on takeoff.

I don't remember the calibration factor I'm using for my Red Cube, but my fuel totalizer (Grand Rapids EIS, for what it's worth) but since I initially calibrated it the thing reads about .8 gallons high (indicating I've burned more than I actually have) in 100 gallons consumed, according to my records.

My home field is at 100 feet MSL. We've actually had some standard days around here lately (California drought, yay, but it makes for great flying weather).

I have done a WOT throttle full rich to peak EGT test, at various altitudes. Typical EGT rise is around 190? F.

Oh yeah, Hartzell blended airfoil prop.

Per post #15, it seems that the real issue here is that something changed.

Precision Airmotive's documentation on the Silverhawk injection system has something that might be of interest. Have a look at section 10.0:
http://www.precisionairmotive.com/Pu...s/25-020_a.pdf

Superior's operator's manual for my engine lists a maximum fuel flow at full rich of 108 pph, for what it's worth.

I meant 500 AMSL (Five hundred) not 5000.

Is your 1000' quoted AMSL not AGL?

Unless we know the density height, but lets assume it was 2000' but with EGT values in the range of normal, barring advanced timing, then doing a reverse engineered guess like I did on Bob Redmans that would give an equivalent of about 16.6GPH.

What can we deduce from this, perhaps you have the fuel flow but due to boost pump being on it under reads? Maybe the K factor is not right? Maybe the density height is higher? Maybe your timing is not accurately 25DBTDC and this offsets the lower FF.

This is a very difficult thing in internet posts, one of the reasons we do a 2.5 day course on engine management and EMS diagnosis. And even then there could be a lot more.

If you have some data files, and if they are from a system like the Dynon which captures everything I am happy to take a look.

As for the rule of thumb, it is exactly that and applies to NA engines at typical standard CR's. It is really about 2-3% less than that HP/10 but it is near enough. It all relates back to the required BSFC for detonation margin and that does vary from engine to engine.

Ohhh and an ISA day.....I have seen a couple but you do have to be lucky! :D

David,

Just to follow up and answer your questions...my home field elevation is 1000' MSL, so those were the numbers I was quoting (but there's virtually no change at 2000' MSL or 1000' AGL). Red cube is located after the fuel injection servo, before the spider, and has been calibrated (filling up, even 3/4 tanks because I don't run them dry, the actual vs. computed values are within .1 gallon). I don't see how having the boost pump on would change the value (the fuel flow transducer has no way of knowing whether there is a boost pump or 3 or if any or all are on or off), so that doesn't seem likely.

I just did the mag timing check at annual...dead on at 25 BTDC, just like it was a year ago.

So back to my questions...essentially, this engine is set up the way it came from the factory and was run on the test stand. Is Lycoming wrong in the way they set up their engines?

Are you saying that it should be 18 gph (i.e., 3.3 gph higher than best power at rated power per the chart, or 22% higher) to avoid the "red box"? If so, I can understand that...

Assuming all that, how do you increase FF if, as I've said, the system is already "at the stops"? (N.B., I have no intention of doing this, short of an unbelievably compelling reason to do so, and with the concurrence of the manufacturer...especially given that it looks like 100% of the responders here with identical engine/prop combos are seeing essentially the same FF).

I'm genuinely trying to learn here, but I'm also hesitant to change a system which is as the factory set it up and which has performed flawlessly to date...

BTW, David...thanks for the PM...reply sent! Appreciate the offer to help...