Another new feature suggestion- better LOP function

[pylotttt]

I have another item that I feel could be improved. better LOP function, more like the Cirrus where it puts a marker at highest egt as well as + or - next to temp offset. Maybe a different color for the temp bar between lean and rich operation.

 

[Raymo]

EGT temps are mostly meaningless. It's the FF spread when each cylinder hits its peak temp that matters. Shoot for .5 GPH or less spread for best LOP ops.

 

[preid]

I’m waiting for the GAMI guru, mr Brown, to chime in, but raymo Is correct, it’s about having all the fuel injectors matched and being very close from first to last. I get the concept of 100f ROP and 50 LOP, but I know my plane so we’ll that having a gauge tell me where I am in relation to peak wouldn’t be used, I see 10.1GPH and know I’m at 55%. Works this way no matter what altitude I’m at, I also follow the GAMI guidance to lean to a egt number from 1000 AGL and keeping at egt number all the way up the climb.
my point is, you have a good idea, but once one gets their plane tuned you don’t need a gauge to tell you where the LOP is, you just know what numbers to expect and fly that every time.Also a tuned engine will get very different results than a stock .028 jet across all lycoming cylinders.

 

[pylotttt]

I guess I should have said lean function not LOP. My engine is not fuel injected so no LOP operation for me.

 

[DBRV10]

I guess I should have said lean function not LOP. My engine is not fuel injected so no LOP operation for me.

Not true at all. Get your engine running well, no intake leaks, good plugs and maybe use a small amount of carby heat to keep the carb temp above 10dC and you may just find all is good. Many Carby planes fly LOP, it just takes some effort to work out your sweet spot.

If you have a fixed pitch prop, ignore the lean find function completely, use a 100 RPM drop from WOT. Lean to peak RPM then another 100-120 RPM and you are there. Works at all altitudes.

 

[DBRV10]

I’m waiting for the GAMI guru, mr Brown, to chime in, but raymo Is correct, it’s about having all the fuel injectors matched and being very close from first to last. I get the concept of 100f ROP and 50 LOP, but I know my plane so we’ll that having a gauge tell me where I am in relation to peak wouldn’t be used, I see 10.1GPH and know I’m at 55%. Works this way no matter what altitude I’m at, I also follow the GAMI guidance to lean to a egt number from 1000 AGL and keeping at egt number all the way up the climb.
my point is, you have a good idea, but once one gets their plane tuned you don’t need a gauge to tell you where the LOP is, you just know what numbers to expect and fly that every time.Also a tuned engine will get very different results than a stock .028 jet across all lycoming cylinders.

What do you want from me?

 

[DBRV10]

Lastly, the Lean Find functions help you determine your richest and leanest cylinder. They are great concept teaching tools. They are sub-optimal in flight tools.

Work out your richest cylinder, do a big mixture pull, then when things have cooled off (couple of minutes) find peak from the lean side with that richest cylinder, using raw data EGT. Then roll back the appropriate amount, that could be 10dF up high, or 60dF down low.

Simple as. Software is easily confused which if you trust it will confuse you even more!

 

[lancair360]

Keep in mind the peak power of abouy 100º rich of peak is only for fixed mag timing. If you have dual electronic like I do then the percent power setting on the EMS is about all you have to go on. Totally different ballgame with adjustable timing.

 

[DBRV10]

Its at about 80dF ROP, and the timing is not much of an influence as we see on the dyno (Carl Goulet memorial dyno - GAMI Ada OK). How much influence do you believe you get? And how are you measuring it? Remember this is a fixed speed scenario (RPM) so a lot of things remain very static.

You may find there is nothing in it ;-)

 

[lancair360]

I can make peak power much leaner that 100º ROP. There's a band from very ROP to near peak that is all power, just changing fuel flow. Timing is doing the job I think. And my LOP operation is a very narrow range. Totally different and more narrow LOP range than my IO-470 on my Bonanza with GAMI injectors. It's just different, using the Dynon EMS makes it easy.

 

[DBRV10]

I know what you think is happening and it is all explained here. Timing is not doing the job, your Bonanza with its IO470 is not as reactive (perception) as I assume your Lancair is.

The dyno data is pretty constant.