D 120 EGT interpretations-need help

flightlogic · #1 12-15-2013, 07:01 AM

Learning to read the Dynon lean function data, but not sure what some of the symbology is showing. If you operate on of these, please jump in and offer advice here. In the lean mode, the absolute temps of each cylinder go away and are replaced by order of peak and delta numbers. They seem to go negative at that point. If I reverse the movement of the mixture lever, to go ROP... the numbers still show a negative sign. Is the intent of the minus, just to show that they peaked? I sort of expected them to show negative if I continued to lean, and the temps dropped off. If I went back to the rich side, I thought they might switch to a plus sign. Have not seen that. Intend to port data from the GPS to give the Dynon altitude data, and then get some percent power info... but the power cable to the Garmin only has 14 VDC... no data wires. If they are going to mold a plug, and put four pins in the end... you would think they would run some wires too. Guess I am just dreaming. Anyway, the pilot guide is sparce in the leaning section, so any owners that are well past this point in learning the software can be a big help to me. TNX !

Brantel · #2 12-15-2013, 07:03 AM

You have to look at the LOP or ROP indication.

You are only at PEAK TEMP at PEAK. Either side of the curve is Negative of PEAK TEMP.

Use the LOP/ROP to know which side you are on....

To get the LOP/ROP indication you must have Percent Power working.....

Garmin has cables available that have all the wires you need in them. They historically don't put the data wires in the cables that are not intended to be used in this manner.

It is pretty easy however to determin which side of peak you are on by feel. Just lean till it gets rough and you will know you are on the LOP side.

flightlogic · #3 12-15-2013, 07:11 AM

Thank you! I won't look for plus signs anymore

flightlogic · #4 11-11-2014, 06:31 PM

After a year with the CS and carbed 320, I still have not found the leaning function to be of much use.
I had wondered if running carb heat might allow me to go lean without the roughness I experience due to imbalanced fuel distribution.... ???
Oddly, after replacing the Dynon carb throat temp probe... I see pretty warm temps all the time. Not a worry for ice, which is good.
BUT, as I add heat.... the probe driven temperature goes down.
(I can hear the result in the engine.... so I am pretty sure the density altitude in the carb went up.... with a slight loss of power as expected) But, every time... the temp drops... not rises.
Any distinguished learned theories out there? Down under welcome too.