N796SP has just been outfitted with an EDM-700 engine analyzer with per cylinder CHT (cylinder head temperature) and EGT (exhaust gas temperature) read outs! (It's put next to the Tach.) This provides more engine data and leaning features than G1000 equipped C172SP's, and allows pilots to make sure CHT are lower than 400F at all times (<380F is better). If the engine is the heart of an airplane, then this is its heart monitor for
each cylinder. Precise leaning is now a single button operation. This not only saves fuel, but also burns cleaner and gives the pilot EGT and CHT information to keeps the CHT temperature nice and cool.
Typical leaning procedure:
Upon reaching cruise altitude, make sure power setting is 75% or less. Pull mixture out to approximately 50 degrees rich of peak. Press the LF button (Lean Find, right button), start leaning slowly about a quarter knob turn a second. Continue to do so until it automatically finds the first cylinder to peak and EGT starts to actually drop in temperature (I find this to be about 1530F). This is the peak, and the EDM-700 will display LEANEST. If you forget what the peak temp was, just hold down LF for 2 sec and it will show it again. At this point, you can start to enrichen it to about 100 degrees rich of peak (around 1430F I found).
You can also press STEP to manually step through the digital read outs of all the cylinder's EGT and CHT's. Press LF then STEP again for it to start to automatically cycle again during the flight.
Readings:
I recommend John Deakin's articles on avweb.com for detailed discussions for best leaning practices.
http://www.avweb.com/news/pelican/182179-1.htmlhttp://www.avweb.com/news/pelican/182176-1.htmlhttp://www.avweb.com/news/pelican/182583-1.htmlhttp://www.avweb.com/news/pelican/183094-1.htmlPlease keep the
CHT < 380F and
EGT 1350-1450F for long engine service life, and keep the owner happy.
