M20JFlyer Posted May 5, 2014 Report Posted May 5, 2014 Just finished install of the JPI and broke it in on trip from SAT to KILM by way of memphis . Trip was approx 2,300 nautical at 9500 going 6500 returning to SAT-Texas . OAT temps were similar at 50F To and from Prior to 830 had the shadin mini fuel flow and insight EGT/CHT MY OBJECTIVE : learn from this group what are parameters of ... Or is there such a thing??? as a sweet spot OR A never exceed hot spot on EGT . { not asking was 830 correct choice or if LOP vs ROP} I prefer my CHT @ 350 to 380 in cruise an oil temp + or - 15 degrees of 200 depending on OAT PLANE Is a 91 j with the original A3B6D with 1,100 hours since(LYCON in California OH ) 2460 TT engine What is best way to find existing threads on the EGT TEMP on the mooney space forum?? Never to old to learn M20J flyer
carusoam Posted May 5, 2014 Report Posted May 5, 2014 It may help to spell out exhaust gas temperature... The search function has a limitation on 3 letter words. Keep in mind absolute EGTs are a function of the location of the probe and do not carry much weight. Peak EGT in relation to the neighboring cylinders in combination with FF@peak is the key take-away from this instrument. Have no fear.... You have opened the LOP/ROP box now!
Cruiser Posted May 5, 2014 Report Posted May 5, 2014 EGT is in itself not a meaningful parameter. It is a reference parameter. That is, you use EGT to find the peak temperature. Many things can effect the EGT readings most importantly being the location of the probe in the exhaust stack. So your numbers may be very different from my numbers but we both may be running our engines exactly the same way. Just getting different outputs on the EGT. you will see this variation within your own engine. Cylinder from cylinder and the EGT values will not be the same. That being said, Common values you can expect to be close to would be 1275° F EGT full throttle (WOT) full rich takeoff power near sea level. Peak EGT some where around 1500°F
M20JFlyer Posted May 5, 2014 Author Report Posted May 5, 2014 Thank you Carusoam The new JPI EGT probes were installed in same holes as original insight at factory. I will admit running EGT's over 1400 seem excessive (ie 1420 -1430) and it is easy to get there. I know there is an extremely good bunch on this forum... And I need to be punched and prodded some to learn new ways. I am a convert to dare I say it LOP BUT that is not what my mission is on this post. Mostly would love others opinions 1
Bob - S50 Posted May 5, 2014 Report Posted May 5, 2014 I echo what cruiser said. The actual EGT is not important. From what I've read it is just an average of the temperature of the exhaust that flows past the probe. Since the probe is only exposed to hot air for about 1/4 th of the engine cycle, it is much lower than the actual temperature of the gases that flow past it. Can't remember exactly but I think I read those gases are actually closer to 3000F or 4000F. With that said, here is what I see on our '78 J: Takeoff: around 1250 to 1300 (I try to maintain that temp during the climb). Cruise peak: around 1450 to 1520. Bob 1
Marauder Posted May 5, 2014 Report Posted May 5, 2014 A lot of what you get for an actual EGT depends on probe location. I don't know if the JPI specifies the length down the exhaust tube, but I have seen them mounted in different locations on the stack on different planes. It wasn't a lot (a few inches difference) and I am not sure how much impact it had on the absolute number. Sent using Tapatalk
N601RX Posted May 5, 2014 Report Posted May 5, 2014 If I remember correctly JPI says 2-4", but to be sure they are all the same distance. They also mention that the closer they are the shorter life they will have.
KSMooniac Posted May 5, 2014 Report Posted May 5, 2014 Try these guys www.advancedpilot.com to learn all you need to know about intelligent engine management. Worth every penny. 1
carusoam Posted May 5, 2014 Report Posted May 5, 2014 The O has the ships EGT gauge at the confluence of three exhaust streams on one side of the engine. The JPI is closer to the exhaust valve in the individule tubes... Best regards, -a-
Piloto Posted May 6, 2014 Report Posted May 6, 2014 I have the EI UBG-16 and works great. I LOP to about 20F lean for lower CHT and lower fuel flow. More than 20F LOP reduces the airspeed too much for me. Mine peaks around 1400F to 1420F. José
PTK Posted May 18, 2014 Report Posted May 18, 2014 Just finished install of the JPI and broke it in on trip from SAT to KILM by way of memphis . Trip was approx 2,300 nautical at 9500 going 6500 returning to SAT-Texas . OAT temps were similar at 50F To and from Prior to 830 had the shadin mini fuel flow and insight EGT/CHT MY OBJECTIVE : learn from this group what are parameters of ... Or is there such a thing??? as a sweet spot OR A never exceed hot spot on EGT . { not asking was 830 correct choice or if LOP vs ROP} I prefer my CHT @ 350 to 380 in cruise an oil temp + or - 15 degrees of 200 depending on OAT PLANE Is a 91 j with the original A3B6D with 1,100 hours since(LYCON in California OH ) 2460 TT engine What is best way to find existing threads on the EGT TEMP on the mooney space forum?? Never to old to learn M20J flyer Some info on the topic at hand you may find useful. http://www.eaavideo.org/video.aspx?v=1778564324001 http://www.eaavideo.org/video.aspx?v=1316946190001
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