Installed GAMIjectors...

I think the idea was that the induction leak is going to be past the manifold pressure sensor and in an area where it will mean more air for one cylinder. Say the leak is likely at the intake manifold / cylinder junction. The amount of air coming through a fixed orifice or leak (in case of a NA engine) is going to be different at 3000 than 8000 feet, so the egt pattern will be different.
 
KSMooniac said:
I'd make darn sure you don't have an induction leak or ignition problem first before buying the GAMIjectors. It seems just about every Lycoming IO-360 (and especially the -A1B6/A3B6(D) variants) run great LOP on stock injectors, provided everything else is up to par. I fear you might spend the money on the GAMIjectors and then find the same results as you have now, so I'd do some troubleshooting first.
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Well, I'm not a mechanic, but my mechanic has been over the engine and the fuel system pretty thoroughly and can't find anything wrong. Yes, there was an induction leak as well as a clogged injector, at different times, a year or two ago. But they were both taken care of before I ran the lean test. I know that everyone seems to say the same thing, you shouldn't need GAMIs on an IO-360, the stock injectors are really well balanced. Lucky me. :(
 
tmyers said:
I remember those days, partly with wanton and partly glad that's over.

I thought you would have jumped on the GAMI spread question with both feet Ted.

I have stock injectors on my IO-360 and between weather, work and this darn cold haven't been able to get it out and really test the LOP abilities. What would be considered an acceptable spread and at what point should I think GAMI's?

I have read everything I can find from the Gray people and they don't sound like they like LOP much. What say Ye?
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Our Arrow II will run smoothly until the fire goes out for lack of fuel, no GAMIs. Just depends
 
dell30rb said:
I think the idea was that the induction leak is going to be past the manifold pressure sensor and in an area where it will mean more air for one cylinder. Say the leak is likely at the intake manifold / cylinder junction. The amount of air coming through a fixed orifice or leak (in case of a NA engine) is going to be different at 3000 than 8000 feet, so the egt pattern will be different.
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Probably not much different with the turbo'd engine in the 'kota. The hint was "30 inches"
 
30" cruise manifold pressure sounds good. I need to borrow some turbos.
 
Ted DuPuis said:
30" cruise manifold pressure sounds good. I need to borrow some turbos.
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It's easy in cruise since it's always the same 2400 & 30. High DA departures are fun too.
 
dell30rb said:
30in would be above atmospheric pressure at altitude so the leaky cyl would be richer
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Do we really have to get into choked flow? The flow difference caused by the pressure between difference 3,000 and 8,000 feet will be minuscule unless the orifice is large enough to detect visually.
 
Clark1961 said:
Do we really have to get into choked flow? The flow difference caused by the pressure between difference 3,000 and 8,000 feet will be minuscule unless the orifice is large enough to detect visually.
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Maybe true for a turbo charged engine as the pressure differential is in the other direction (the intake manifold is at a higher pressure than ambient), but if the engine is a NA injected, then the MP at 8000 MSL will be close to 21 inches about 1 inch differential lower than ambient, but at 3000 MSL and running the engine at 21 inches, it will have a differential of about 5 inches. If there is an induction leak, it will have little effect at 8000, but a much larger effect at 3000 and the pattern will be different near the leak.
 
John Collins said:
Maybe true for a turbo charged engine as the pressure differential is in the other direction (the intake manifold is at a higher pressure than ambient), but if the engine is a NA injected, then the MP at 8000 MSL will be close to 21 inches about 1 inch differential lower than ambient, but at 3000 MSL and running the engine at 21 inches, it will have a differential of about 5 inches. If there is an induction leak, it will have little effect at 8000, but a much larger effect at 3000 and the pattern will be different near the leak.
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Keeping it in context we were discussing the difference in leakage for 30" of manifold pressure. Of course context may not matter to you.
 
Clark1961 said:
Keeping it in context we were discussing the difference in leakage for 30" of manifold pressure. Of course context may not matter to you.
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You obviously haven't read the majority of the posts or you might understand the context, then again ...
 
Clark1961 said:
It's easy in cruise since it's always the same 2400 & 30. High DA departures are fun too.
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Yeah, the Navajo was nice in that regard - always burns what it always burns. I took off from KAPA in the Chieftain and KJAC in the straight Navajo. After a little turbo lag, man did we get going.

Turbos would be nice. Not happening anytime soon with this plane.
 
Clark1961 said:
Keeping it in context we were discussing the difference in leakage for 30" of manifold pressure. Of course context may not matter to you.
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It would still matter for 30" of MP if you had a leak. At 3000 feet, that is positive pressure on the manifold. Same for 8000. At 8000 there will be a larger pressure differential between your 30" manifold and outside pressure than at 3000. So at 8000, more air will escape and the cylinder nearest the leak will be richer than the rest.

A leak will affect both turbo and NA engines but in opposite ways. A NA engine will have a lean condition at a leaky cylinder and a turbo will have a rich condition.
 
John Collins said:
You obviously haven't read the majority of the posts or you might understand the context, then again ...
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Sure John, whatever you say. Never mind that I specifically mentioned 30". It's called thread drift, perhaps you can deal with it, perhaps not.
 
dell30rb said:
It would still matter for 30" of MP if you had a leak. At 3000 feet, that is positive pressure on the manifold. Same for 8000. At 8000 there will be a larger pressure differential between your 30" manifold and outside pressure than at 3000. So at 8000, more air will escape and the cylinder nearest the leak will be richer than the rest.
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Now consider the actual % change in pressure relative to 30". The leak would have to be large to significantly affect the mixture.

The response to the same size leak with NA and turbo will be very different.
 
Clark1961 said:
Are those for when the red lever is pulled too far back?
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Nope, after my emergency I was to puckered up to need depends:goofy:

My first law of aviation is now "never under estimate your butt's ability to suck the seat covers off."
 
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