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