GAMI injectors, do they work?

Flying Tips and Advice from The Colonel!
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digits
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Joined: Thu Jan 16, 2020 4:15 am

Since it involves leaning and CHT, it seems it would fit in great with the last few topics ;-)

So, anyway, are GAMI injectors worth it in a -for example- Continental IO470? Will you actually save money by operating as lean as possible? Or will it break other stuff later on?

Seems like some people are claiming 10-15% of fuel savings. I'd mainly be interested for the range increase of the plane.

Thoughts?


Big Pistons Forever
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Yes they do work. The big advantage is that you can run significantly lean of peak with smooth engine operation. The stock Continental injection system can have significantly different flow rates at each cylinder and still be in spec. When you try to run LOP the engine won’t run smoothly.

I flew a friends IO 550 powered C210. He had GAMI injectors and the latest engine analyzer. The interesting thing I found is if you used the analyzer to go LOP you wound up with a mixture setting just above the start of rough running for the engine, so I started to just lean until roughness and enriched it just enough for smooth operation and wound up exactly where the electronic magic “lean find” system had me with a lot less button pushing 8-)

Personally I found, that at least for efficient airplanes, the gain wasn’t that great. Leaned LOP you lost 10 kts TAS so while the fuel flow was lower the trip burn advantage wasn’t as great as I thought it was going to be plus flight time increased. I could see LOP operation be a lot more advantageous for draggy slow airplanes like floatplanes though.

The one big advantage of LOP operation was on really hot days. Running rich of peak it was impossible to keep CHT’s below 380 unless the mixture was well above the best power setting or the cowl flaps were opened. LOP however the CHT’s dropped to the 360’s with the cowl flaps closed.

Finally guys seem to think LOP operation is some new age magic. When I flew the DC6 we operated LOP as set on the BMEP gauge as per the AFM procedure. The AFM was written in 1953…..
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Colonel
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I have GAMI fuel injectors in my Lycoming AEIO-540's. They are nice because they reduce the
spread of the EGT's, which I like.

Image

See how nice and tight the EGT's (top) are in flight? The wiggles in the middle are me doing acro -
wild changes in airspeed and altitude and power (I cut the power after the kick in the hhead).

If I'm flying something with no instrumentation, I just lean for best airspeed. As I've said before,
if you have the instrumentation, lean for hottest cyl just under 400F. In climb, cruise, whatever.

Here's another flight with leaning to 12 gph at 20 inches in cruise:

Image

Again, weird wiggles in the middle are surface acro. Most people don't do that.

I know for a certain power setting (MP/RPM) what GPH to dial in with the mixture. Then, I look
at the CHT's to confirm it's under 400F. The EGT delta (max spread) being tiny is nice but frankly
mostly a fetish, and is the last thing to look at. You just want all the cylinders doing the same thing.

TL;DR I can't financially justify GAMI injectors and logging engine monitors, but my engines
have never run better.
45 / 47 => 95 3/4%
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Scudrunner
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Engine monitors are definitely on my list of upgrades. Was looking at the Garmin 275 EIS. My thinking is two gauges will replace everything to the right of my radio stack.
73AA13BF-B98B-4246-873F-BFE9B6A41CDA.jpeg
And the ADF I’ll let my 6 year old take it apart and reassembled for sport .
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5 out of 2 Pilots are Dyslexic.
Squaretail
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And the ADF I’ll let my 6 year old take it apart and reassembled for sport .
But then how will you get the hog reports on QR77?
The details of my life are quite inconsequential...
David MacRay
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I question the equipment they broadcast AM radio with.

I listen to 1060 sometimes driving around and it sounds worse than it did back in 1976, listening to Paul Harvey and swap-shop on CHAT AM, out at my grandmas farm in Saskatchewan.
Squaretail
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I think most of the high powered transmitters are gone, the highest in the CFS is 50000 W, though I remember Red Deer's Radio Seven when it was still around bragged about being a 56000 W power station, and you could receive it flying over Winnipeg. Trivia bit: CKRD was where Ron McLean started his career as the sports guy.
The details of my life are quite inconsequential...
David MacRay
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I love Z-98.9. Should have bought a house in Springbrook. I could potentially be flying a Skywings 172 today.
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