647jc

647jc

Well Known Member
I?m experimenting with the Dynon EMS Lean function and was wondering what others are experiencing. For testing I start the lean process at about 6000 ft and 75% power (Lyc O-320 160hp carb & Sensenich FP prop). I invoke the Lean function on the EMS menu and then start pulling back the mixture control. I know about when the engine will start to stutter so prior to that I stop pulling and start twisting the mixture control. The engine will eventually start to stutter before I see any of the cylinders peak. I?m a bit hesitant to continue leaning to see if any of the cylinders will begin peaking with the engine already stuttering but maybe I should. The exhaust gas temps look OK, about 1350 when this starts occurring and all the cylinders are fairly close to each other in temperature. Is there any risk of damaging the engine if I continue to lean the mixture once the engine begins to stutter or is damage a risk only if I run the engine for an extended period of time and allow the temps to exceed Lycoming?s recommendations? I know the Dynon Lean function will detect peak temperatures because if at the point the engine starts to stutter I slowly enrich the mixture, each cylinder temp peaks but of course this is not the true peak I am looking for. I have no experience leaning with EGT gauges, I normally just lean to where the engine starts stuttering and then back off a bit on the rich side. Sorry if this question sounds a bit basic but I?m trying to learn to do it the correct way. So, what are others seeing / experiencing using the Dynon Lean function? Are others experiencing pretty rough engine running before the Dynon EMS detects any EGT peaks?
 
Joe,

I keep leaning and eventually they will all peak. Once that happens, push the mixture in until the last cylinder is 100 degrees ROP. That's per Lycoming.

Now, if you were to lean it like you did that old Cessna you learned in, meaning, lean it until it runs rough and push it forward until things smooth out, you are running about 60 degrees ROP. Right where Lycoming tells you not to run them. Go figure, I'm not really sure where to run them.

If you want, pull the power back to say 65% power and try leaning it again. That will guarantee you won't hurt your engine.
 
Carb heat

Hi Joe,

Try it again with full carb heat or the throttle about 1"MP off of WOT. I'll bet you can get it to run smoothly as the Dynon shows the cylinders snapping LOP.

Drop me a PM if you want to talk live. I might be in Ames this weekend with the plane. Maybe we could hook up.
 
Dual mags by any chance? You'll need a lot of luck to get 'em LOP... Now, with EI.. you may/should be able to do it..... just some first hand experience..
 
Thanks all for the input. I should have mentioned I have 2 Slick mags, no EI. I have no intention to run LOP, I just would like to see the Dynon EMS detect EGT peak via the inbuilt leaning function before I kill the engine or damage something going too far lean :eek:. I would have thought by the time I feel or detect rough running at least one of the cylinders would have peaked and the Dynon would have detected it.

Pete; Weather permitting I'll probably be flying circles over Boone this weekend (10 hours to go in phase I). Ames is also within my circle of terror so let me know if you plan to go to Ames this weekend. I have a hangar at Ames that is currently empty and you are welcome to use it if you want.
 
Thanks Joe!

I'll let you know. We are dealing with some health issues in the family down in Ames and it would be great to have a place to stash the bird if we need to come down on short notice.
 
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