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Carburetor mixture distribution

Any update

Long x country yesterday wishing I could run LOP. Any updates on this mod?
 
Still working well

I am still running it and it works well on my combination. (Sam James filter assembly with home brew plenumn on carb)
Others who are running Van's FAB report no change. I suspect the filter in the FAB serves to straighten the air and therefore no straightener is needed.
It's going to stay in mine though....
 
Thanks Don

I have the vans Air box. My GAMI test shows 0.6 which is just outside the .5 recommended for LOP, but that's at 70% power. It gets real rough when LOP. But I haven't tried LOP below 65% I think I'll do some test points with carb heat etc.
 
I am working on the straightener, but have found that I can fly LOP pretty well at 60%-65% power as-is. O-360-A-1-A, FP, 2300RPM, <20" MP, 6GPH.
 
Something to note about the Vans FAB airbox vs. the duct to the carb approach. A duct that has the same diameter as the carb inlet will see the same air velocities as the carb. The Vans FAB airbox at the carb (or any other airbox) expands and decelerates the air greatly reducing velocity just prior to the carb entrance. That probably will have an impact of flow straightner effectiveness.
 
Now that the weather is warming up I
am having cooling issues. Working on the fix for that now:( Gotta get those
wheel pants and gear leg fairings on too.:)
Pants and fairings buy around 10 knots... Will help cooling some.

Have you opened the cowl exit?
 
Pants and fairings buy around 10 knots... Will help cooling some.

Have you opened the cowl exit?

Yea, this is an old thread. Pants and fairings added 17 knots:) sealing the baffels better helped cooling to the point it's a non-issue now.
 
That Cool ;)
out pants and fairings added the same.
Interesting was that the little front gear fairing added 5-8 kts
 
Last week I was playing around with idle mixture settings with a Rotec on an O-360 and was able to get it to idle reliably at 150RPM. Of course we're not keeping it that way but making a lycoming run like a steam engine generated some laughs. Only possible with good fuel distribution...
 
This weekend I installed an airflow straighter on the inlet to my O-360-A1A FP. Before this modification I could run LOP to about 6.5 gph/2300RPM. Any attempt to run WOT (or even above 2300) and it would get very rough. #3was always the last to peak, #1 and #2 always peaked very close to each other. The fuel flow between #1&2 peaking and #3 peaking was around 0.7 gph.

My test flight after the addition was very short. At 6,500 feet, 2,500RPM all 4 cylinders peaked at the same time, and the plane seemed happy. I could run WOT at about 25 degrees LOP, but not much more. Even there it was a little rougher that I would feel comfortable flying. I tried re-leaning at 2,200RPM and saw that #'s 1-2-3 all stayed together and #4 was last to peak. I did not measure the gph difference, but it seemed to take a couple of turns of the mixture knob. It did not run well at the old sweet spot of 2300/6.5gph

I will not know if this is a win or a loose until I get some more flight hours, but I can say for sure that it made a change in the F/A distribution.
 
So where did you guys land on this?

I came across this thread and I am interested.

I fly a cozy mk3 and I am going through the same lop leaning issues discussed here. How many hours on this install? Has it proven reliable?

From reading the thread it sounded like one guy loved it, one guy didn't, and one guy was undecided. I would love to know your thoughts. Thanks!
 
I came across this thread and I am interested.

I fly a cozy mk3 and I am going through the same lop leaning issues discussed here. How many hours on this install? Has it proven reliable?

From reading the thread it sounded like one guy loved it, one guy didn't, and one guy was undecided. I would love to know your thoughts. Thanks!

I am still flying the mod. Well over 150 hours on it. It is not the complete solution, however it made a huge difference in my application. I can now run LOP no problem as long as the throttle is wide open. Even slightly closing it creates distribution issues though not nearly like it was originally. Its a mod worth experimenting with.
 
Repeat the mod

Don,

I have always thought about doing this mod but fearful of injestion risk. Can you post a photo of how you did the mod and how you would change anything. If you did it again.

Paul
 
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