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  #1  
Old 03-30-2021, 02:21 PM
Vans101 Vans101 is offline
 
Join Date: Apr 2016
Location: San Jose
Posts: 72
Smile Fuel Nozzle Restrictor Size Advice Please

Hi Cyber Friends!!!

I am trying to dial in the EGT LOP curves and could someone PLEASE provide a recommendation on the restrictor sizes?

First question is...If you are leaning the mixture and all of the EGTs are rising and then one cylinder EGT peaks at a higher GPH than the others does that mean that the cylinder is leaner or richer than the others? I am thinking that it is leaner because it did not have enough fuel fuel supply and it leaned out sooner as a result.

The second question is what size fuel restrictor do you recommend going with to balance out the LOP EGT curves?

All cylinders currently have 0.0280 restrictors. Here are 4 LOP sweeps.

#2 18.9
#4 18.4
#5 17.8
#1 17.6
#6 17.5
#3 17.4


#2 14.6
#4 14.6
#3 12.4
#5 12.4
#6 12.4
#1 12.2


#4 15.5
#2 15.2
#3 14.2
#5 14.2
#6 14.2
#1 14.2


#4 15.0
#2 14.6
#3 14.0
#5 14.0
#6 13.8
#1 13.7

THANKS!!!
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  #2  
Old 03-30-2021, 02:37 PM
Raymo's Avatar
Raymo Raymo is offline
 
Join Date: Nov 2014
Location: Richmond Hill, GA (KLHW)
Posts: 2,322
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As you were thinking, first to peak is the leanest; last to peak is richest. It is important to lean very slowly and smoothly to get consistent numbers. You should also consider doing the check at different altitudes.

Nozzle size adjustments should be discussed with your FI manufacturer. If the nozzles haven't been cleaned in a while (within the last year), that would be a good place to start before tuning starts.

If you have engine data you can upload to the SavvyAviation website, that would help you and them better understand what needs done. Access is free to analyze your own data.

Your spread is quite wide so it could definitely benefit from some nozzle tuning.
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Last edited by Raymo : 03-30-2021 at 02:39 PM.
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  #3  
Old 03-30-2021, 02:37 PM
BobTurner BobTurner is offline
 
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Location: Livermore, CA
Posts: 7,349
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Your understanding is correct, #2 and #4 are running leaner than the others.
As you can see by your data, you likely can’t achieve perfect balance for all power settings. You need to balance for ‘typical’ cruise settings. For me, that’s 9500’ or 10,000’, full throttle, 2300 rpm or so. I prefer trading some speed for economy, not everyone does. Your grouping #2 seems closest to those conditions, so I’d start by going 0.001” larger (0.029”) on #2 and #4. There will be some interaction with the other cylinders, so you’ll have to iterate and fine tune. You can buy variations as small as 0.0005”.
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  #4  
Old 03-30-2021, 02:39 PM
Carl Froehlich's Avatar
Carl Froehlich Carl Froehlich is online now
 
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Location: Dogwood Airpark (VA42)
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I imagine this GAMI spread of 1.5GPH ran pretty rough at LOP. Is this a Lycoming IO-540 or what?

#2 and #4 are peaking at a higher GPH than the rest - that means those cylinders are leaner.

For my flying, I lean the rich cylinders (as in not adding fuel for the lean cylinders). I suggest replacing the nozzles in #1, #3, #5 and #6 to 0.027” and then refining from that point after getting new data with these replacement nozzles in place. As you are starting with a very poor GAMI spread I suspect 2-3 iterations will be needed. Remember a change on any cylinder has a secondary (as in smaller) effect on the other cylinders.

To verify, I recommend sending your data to Don at AirFlow Performance and get his recommendation for replacement nozzles.

Carl
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  #5  
Old 03-30-2021, 05:12 PM
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pilotkms pilotkms is offline
 
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Don’t guess. Go to the Airflow Performance website and do the GAMI spread like Don advises. Download the data into Savvy. Send the results to Don. He’ll advise u the change in restrictors needed, and sell them to u. I did it and mine is now 0.00
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  #6  
Old 03-30-2021, 10:53 PM
Vans101 Vans101 is offline
 
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Location: San Jose
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Thanks so much for the advice.

I do upload the data to Savvy and I have the Performance Plus plan and submitted the data for a professional opinion and one of the technicians there I seem to have a problem communicating with. I uploaded the last flight data and asked for a GAMI spread analysis and asked if I should increase the fuel nozzle restrictors for cylinder 2 and 4 and he responded...

Not necessarily. Your EGT spread varies between only 30F and 100F, both are good spreads...Not sure what your goal here is but I really don't think you can get any better performance by changing the injectors.

So after 3 email bounces it did not seem like the communication was being understood so I thought I would reach out to you all. I took the raw CSV Excel spreadsheet and found the GAMI LOP sweeps from the flight and that is what I included in the first post.

I have a number of extra restrictors with various diameter so I will make the change and report back.

THANKS again for all of your suggestions.
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  #7  
Old 03-31-2021, 06:31 AM
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Walt Walt is offline
 
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Check with Don at AFP but I'm pretty sure for the 360/540 engines we have better success with the .024 or .026 nozzles.
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  #8  
Old 03-31-2021, 07:54 AM
lr172 lr172 is offline
 
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Location: Schaumburg, IL
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Quote:
Originally Posted by Vans101 View Post
Thanks so much for the advice.

I do upload the data to Savvy and I have the Performance Plus plan and submitted the data for a professional opinion and one of the technicians there I seem to have a problem communicating with. I uploaded the last flight data and asked for a GAMI spread analysis and asked if I should increase the fuel nozzle restrictors for cylinder 2 and 4 and he responded...

Not necessarily. Your EGT spread varies between only 30F and 100F, both are good spreads...Not sure what your goal here is but I really don't think you can get any better performance by changing the injectors.

So after 3 email bounces it did not seem like the communication was being understood so I thought I would reach out to you all. I took the raw CSV Excel spreadsheet and found the GAMI LOP sweeps from the flight and that is what I included in the first post.

I have a number of extra restrictors with various diameter so I will make the change and report back.

THANKS again for all of your suggestions.
You need a better opinion than the one you got. He is wrong. You can do much better. Send that data to airflow performance. You will get much better advice and guidance.

Larry
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  #9  
Old 03-31-2021, 07:56 AM
lr172 lr172 is offline
 
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Location: Schaumburg, IL
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Quote:
Originally Posted by Walt View Post
Check with Don at AFP but I'm pretty sure for the 360/540 engines we have better success with the .024 or .026 nozzles.
When I did my 540 overhaul a year ago and had to buy all new injuectors, Kyle recommend .025's for my setup.
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  #10  
Old 03-31-2021, 10:13 AM
Carl Froehlich's Avatar
Carl Froehlich Carl Froehlich is online now
 
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Location: Dogwood Airpark (VA42)
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Just a reminder, you balance the injectors by replacing injector nozzles, not injectors.

At ~$28 each from AirFlow Performance this is a cheap process. I have a collection of nozzles in my hangar (almost all 0.028”) left over from balancing a series of engines.

The feed you got on “EGT spread” is amazingly wrong. Ignore it and whomever provided that advice.

As has been suggested, I always reduce the rich cylinders as most consider the stock 0.028” to be already too big. Don at AirFlow performance can provide good guidance for you on replacement nozzle sizing.

Carl
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