Turbo leaning via EGT

[Jetpilot86]

Just installed an Insight G2 today, in my new to me Bravo, replacing my Insight 602, as a cheap, and quick to install bridge to feed some engine data on my new FOH TIO-540 to @kortopates for analysis.  Here’s an old thread on engine monitors

Since I used the old 602 harness to save install AMU’s for the JPI-930 upgrade next winter,I won’t have TIT, Fuel Flow, or OAT functions via the unit for now.  After frying my brain in the TLS Bravo Power Setting Blog, I’m curious about how the G2 can be integrated into the power management of my Bravo as she seems so tied to TIT for leaning in conjunction with the Analog TIT still remaining in the panel for the time being. For instance, any value added leaning with EGT on the Turbo?

Not looking to get into any LOP areas now as I lack the engine tweaks @DVA has done to even make it possible to run LOP, but use what I have now to run the engine as precisely and efficiently as I can while waiting for next upgrade season.  I just got my beauty and want to fly her instead of just admire her in pieces in the hangar. 
 

Cheers,

[Fly Boomer]

3 hours ago, Jetpilot86 said:

Not looking to get into any LOP areas now

According to Mike Busch, no cylinder (CHT) should ever be allowed to exceed 400° Fahrenheit on your Lycoming.  You can use EGTs as a near-instantaneous proxy for where your CHTs are headed, but it's the cylinders you are trying to protect.  You have a variety of ways at your disposal to keep those cylinders cool -- the red knob is just one of them.

[LANCECASPER]

5 hours ago, Jetpilot86 said:

Just installed an Insight G2 today, in my new to me Bravo, replacing my Insight 602, as a cheap, and quick to install bridge to feed some engine data on my new FOH TIO-540 to @kortopates for analysis.  Here’s an old thread on engine monitors

Since I used the old 602 harness to save install AMU’s for the JPI-930 upgrade next winter,I won’t have TIT, Fuel Flow, or OAT functions via the unit for now.  After frying my brain in the TLS Bravo Power Setting Blog, I’m curious about how the G2 can be integrated into the power management of my Bravo as she seems so tied to TIT for leaning in conjunction with the Analog TIT still remaining in the panel for the time being. For instance, any value added leaning with EGT on the Turbo?

Not looking to get into any LOP areas now as I lack the engine tweaks @DVA has done to even make it possible to run LOP, but use what I have now to run the engine as precisely and efficiently as I can while waiting for next upgrade season.  I just got my beauty and want to fly her instead of just admire her in pieces in the hangar. 
 

Cheers,

Your analog gauges are still the official numbers for your airplane since your Insight is there for supplemental information only. Lean with your analog TIT, not your EGT. Your TIT is measuring the temperature as it is entering the Turbo - you need that number to be accurate. TIT probes fail on this engine every 100-200 hours. When they fail it reads low, meaning that you can cook the turbo and the engine with false readings. On that engine, with a good reading,  I would keep 1600 as your max TIT. Your EGT is only measuring the temp at one cylinder, your TIT is measured after the exhaust of all of the cylinders has accumulated at the turbo inlet.

(Insight makes the G2 in a 6 cyl Turbo version with TIT, and it looks like if you ordered the Turbo version then the CHT, EGT & TIT on the Insight are your certified primary numbers instead of the analog gauges   https://www.aircraftspruce.com/catalog/inpages/g2enginemonitor.php)

There has been a lot written on Mooneyspace about NOT using the POH numbers on this engine if you want longevity. Keep the CHT under 400, 380 preferably. If you do not have good baffle seals you will most likely not be able to do that.

[Jetpilot86]

4 hours ago, LANCECASPER said:

Your analog gauges are still the official numbers for your airplane since your Insight is there for supplemental information only. Lean with your analog TIT, not your EGT. Your TIT is measuring the temperature as it is entering the Turbo - you need that number to be accurate. TIT probes fail on this engine every 100-200 hours. When they fail it reads low, meaning that you can cook the turbo and the engine with false readings. On that engine, with a good reading,  I would keep 1600 as your max TIT. Your EGT is only measuring the temp at one cylinder, your TIT is measured after the exhaust of all of the cylinders has accumulated at the turbo inlet.

(Insight makes the G2 in a 6 cyl Turbo version with TIT, and it looks like if you ordered the Turbo version then the CHT, EGT & TIT on the Insight are your certified primary numbers instead of the analog gauges   https://www.aircraftspruce.com/catalog/inpages/g2enginemonitor.php)

There has been a lot written on Mooneyspace about NOT using the POH numbers on this engine if you want longevity. Keep the CHT under 400, 380 preferably. If you do not have good baffle seals you will most likely not be able to do that.

Keep in mind with MY G2, I’m only getting primary CHT/EGT for the engine and nonTIT on it at all. For some reason a 603 would have been a better choice back in the day, but she came with a 602, so no TIT pre-wired for my new G2. I’m NOT replacing the old harness to keep the AMU’s down until the JPI upgrade next winter, lots of install time/AMU’s, AND get SOME data monitoring until then. Baffles looked good when I saw the engine for the first time yesterday sans cowl. 
 

As I was up late again reading, I found this ancient thread, where @donkaye says on page 3 

On 6/2/2012 at 10:49 AM, donkaye said:

3. Lean by TIT.  This is a turbocharged engine and all the exhausts combine to generate the TIT, so use that to lean.  TIT should never exceed 1650 for engine longevity (forget the 1750 maximum.  Go  there and you won't have an engine for long).  I lean to between 1600 an 1625.  You will find that this is greater than 100° ROP.  NEVER lean to 50° ROP unles you are operating at power settings below 60%.

This implies to me that the peak TIT He’s richening FROM is 1750. Yet, I’ve seen quite a few others talk about leaning to 1550°, or 100°RO 1650°, or 200°RO the TIT Limit. Confused yet? I sure am. 
The times I’ve hunted for actual peak TIT in the 6 hours I’ve been flying this one, I might get to 1675°TIT before she starts running rough, in the 11-12k altitude range. So does that end up making 1625°-1650° in the Red Box @ 75% cruise? Or safely 100-125° under the 1750° limit?
What I’ve discovered so far in my quest for most Kts/gallon while not destroying the engine, is that even here, it’s not very clear what is what, other than No 1750°, or >400°, as many interpret 100° Rich to be 1550°, vs 25-50° RO1650° <shrugs>

@DVA makes a good case for LOP, IF!!!! You have the engine tuned to a premium. At a minimum, he makes the case for Tempest/GAMI as worth the AMU’s whether you want to run LOP or not. 

In the last couple of days, I’ve gone from “I’m leaning just fine” to, I’m in the heart of the RedBox @1650° and a couple twists Rich from there, to who knows. It’s one of the reasons I got the G2 for the interim time, to see what the graphs say. I did the free chapter of APS last night, the rest is having to wait until I get done with recurrent at my day job. 
It appears the G2 will be giving me the most accurate look at the inner workings of the engine, for now, albeit if I’m just using it to keep an eye out for the negative side effects of improper leaning and run the most efficient and fast as I can outside the Red Box.

 
I don’t recall it being this difficult back in my Part 135 turbo days before Digital Engine Monitors some 30 years ago. But then again, maybe I didn’t realize I was as clueless then as I do now. 
If someone is new to Bravo’s reading this, the engine instruments on the Bravo require as much of a scan as the flight instruments as you are chasing multiple limits across the engine panel that are EASY to bust if you over focus on one. 

[N201MKTurbo]

I always run my turbo 4 cylinder Lycoming LOP. I haven't done anything special to make it run LOP, it just does it just fine. After climb, I pull the MP down to 25, then pull the mixture till I can feel the power drop off. Then I set the RPMs to 2400 and the MP to 28". Then I increase the mixture till the TIT is 1525. This puts my hottest cylinder (#2) at 380F. My coolest cylinder (#3) is at about 350. I need to open up the lower gap in the baffling for #2 (as @M20Doc suggested) to even the temperatures. Then I can hit it a bit harder. This has a fuel flow of ~9 GPH and ~160 KTS depending on altitude.

[Shadrach]

Do all of the Bravos need GAMIs to run power settings on the lean side?  
 

This thread interests me. It seems to me that TIT redline is more centered on Turbo longevity, not cylinder longevity. I see that everyone is advocating for using TIT to set power.  I understand why. On the rich side of peak, cylinder to cylinder power variation is minimal even with cylinder to cylinder mixture differences as much as 50-150 degrees from peak.  However, in a perfect world, would it not be better to be aware of both EGT and TIT? Would it not be better to set power with EGT as long as the setting results in a reasonable TIT number.

[LANCECASPER]

On 12/6/2023 at 11:24 AM, Jetpilot86 said:

Keep in mind with MY G2, I’m only getting primary CHT/EGT for the engine and nonTIT on it at all. For some reason a 603 would have been a better choice back in the day, but she came with a 602, so no TIT pre-wired for my new G2. I’m NOT replacing the old harness to keep the AMU’s down until the JPI upgrade next winter, lots of install time/AMU’s, AND get SOME data monitoring until then. Baffles looked good when I saw the engine for the first time yesterday sans cowl. 
 

As I was up late again reading, I found this ancient thread, where @donkaye says on page 3 

This implies to me that the peak TIT He’s richening FROM is 1750. Yet, I’ve seen quite a few others talk about leaning to 1550°, or 100°RO 1650°, or 200°RO the TIT Limit. Confused yet? I sure am. 
The times I’ve hunted for actual peak TIT in the 6 hours I’ve been flying this one, I might get to 1675°TIT before she starts running rough, in the 11-12k altitude range. So does that end up making 1625°-1650° in the Red Box @ 75% cruise? Or safely 100-125° under the 1750° limit?
What I’ve discovered so far in my quest for most Kts/gallon while not destroying the engine, is that even here, it’s not very clear what is what, other than No 1750°, or >400°, as many interpret 100° Rich to be 1550°, vs 25-50° RO1650° <shrugs>

@DVA makes a good case for LOP, IF!!!! You have the engine tuned to a premium. At a minimum, he makes the case for Tempest/GAMI as worth the AMU’s whether you want to run LOP or not. 

In the last couple of days, I’ve gone from “I’m leaning just fine” to, I’m in the heart of the RedBox @1650° and a couple twists Rich from there, to who knows. It’s one of the reasons I got the G2 for the interim time, to see what the graphs say. I did the free chapter of APS last night, the rest is having to wait until I get done with recurrent at my day job. 
It appears the G2 will be giving me the most accurate look at the inner workings of the engine, for now, albeit if I’m just using it to keep an eye out for the negative side effects of improper leaning and run the most efficient and fast as I can outside the Red Box.

 
I don’t recall it being this difficult back in my Part 135 turbo days before Digital Engine Monitors some 30 years ago. But then again, maybe I didn’t realize I was as clueless then as I do now. 
If someone is new to Bravo’s reading this, the engine instruments on the Bravo require as much of a scan as the flight instruments as you are chasing multiple limits across the engine panel that are EASY to bust if you over focus on one. 

You might consider posting a picture of the baffles. The material may look good to the eye, but if the air causes them to lay back they aren't doing their job and the air isn't being forced down over the cooling fins - it's just escaping over the top. If the power settings are good (as described below) and the CHTS are still close to 400 or above the baffles are the number one reason.

This is going to sound crazy, but you can't fly the M20M by the POH and come close to getting the engine to go to TBO.

Even after Lycoming recognized that the TIT allowed in the POH (1750), was way too hot and that they were going through cylinders every few hundred hours, Mooney CEO back then under the French ownership, Jacque Esculier, wouldn't agree to revise the POH. 

Legend has it that Lycoming told Mooney that owners had to keep the TIT under 1650 to stand any chance of making TBO. This would bring the top speed and range down below where Jacque thought they needed to be from a marketing standpoint ("Personal Airliner") and vowed they would never use another Lycoming engine in any of their new airplane designs. (So far that promise has held true.)

Finally what came out of all of it was the Bravo wet-head conversion released in early 1996. A couple years later Lycoming came out with a small booklet on Engine Management  and tried to get it in the hands of owners of Mooney M20M and Piper Mirage (PA-46) airplanes. It mentioned that for the sake of engine life, TIT should not exceed 1650, even though to this day the M20M POH still has the TIT redlined at 1750. The TIO-540-AF1B engine is one of the few engines that Lycoming says must have 25 hour oil changes, as specified in a Lycoming Mandatory Service Bulletin 480F. In a Lycoming seminar at a Mooney Homecoming probably 20+ years ago the Lycoming rep said that with the heat this engine produces, that they saw rapid degradation in the oil's viscosity past that mark. The oil that runs through those extra oil cooling lines past the exhaust valve area sees a greater temperature than in most other engines and apparently breaks down faster. (Once the Bravo (wet-head) conversion was done on this engine the oil temperature understandably went up 15-20 degrees.)

In practice, M20M owners who want their engines to make TBO disregard the high numbers printed on the sunvisor and in the POH.

They keep TIT below 1600 and CHTs below 400, preferably below 380.

They use "53" as the number not to exceed (meaning, as an example, that 29" MP + 2400 RPM = that "53" number).

Even at that number, or other power settings below that, it's still an amazing airplane which stands a good chance of reaching TBO.

[slowflyin]

Mine doesn't require GAMIs.  It will run smooth on the lean side.  My biggest challenge with LOP ops is keeping the TIT in an acceptable range.  14.2 GPH-LOP puts TIT at or above 1650.  I can lean to 13.2 GPH, 1625 TIT without roughness or surging for around a 10 kt penalty.   I'd like to see 1600 or less.   LOP, my highest CHT drops from 385 to 350.  I'm constantly contemplating whether I should baby the jugs or the exhaust.    

[LANCECASPER]

8 minutes ago, slowflyin said:

Mine doesn't require GAMIs.  It will run smooth on the lean side.  My biggest challenge with LOP ops is keeping the TIT in an acceptable range.  14.2 GPH-LOP puts TIT at or above 1650.  I can lean to 13.2 GPH, 1625 TIT without roughness or surging for around a 10 kt penalty.   I'd like to see 1600 or less.   LOP, my highest CHT drops from 385 to 350.  I'm constantly contemplating whether I should baby the jugs or the exhaust.    

Baby the exhaust. Having a cylinder lose compression won't be life-threatening. Having the tailpipe separate and breathe fire into the cabin is life-threatening. 





The previous owner of the third Bravo I owned had run it hot. I looked over the exhaust, but missed this. Glad I caught it soon after purchase. When that separates the exhaust burns through the firewall and into the cabin. There has been loss-of-life over this very issue.

[slowflyin]

9 minutes ago, LANCECASPER said:

Baby the exhaust. Having a cylinder lose compression won't be life-threatening. Having the tailpipe separate and breathe fire into the cabin is life-threatening. 





The previous owner of the third Bravo I owned had run it hot. I looked over the exhaust, but missed this. Glad I caught it soon after purchase. When that separates the exhaust burns through the firewall and into the cabin. There has been loss-of-life over this very issue.

I agree and rarely run near 1600 TIT.  That being said, the lack of data is frustrating.   1750 didn't work so they dropped the TIT max to 1650.  Did 1650 not work?  I've read all I can find and haven't been able to find any remarks regarding 1650 burning up someone's exhaust.  Did your previous owner run 1650 as a limit?  @donkaye has more experience with the Bravo than most and he runs very conservative TIT temps.  He's still doing exhaust work mid-time.  If he had used 1625 or 1650 would he have had a different outcome?  One thread had comments from a gent that had a background in metallurgy, and he was fairly adamant 1650 was good to go.   Wonder how his exhaust is holding up.   In the end, all I can find is these engines need exhaust work, 1750 is bad, 1650 is Mooney's opinion, everyone else seems to lean toward some degree of cooler is better.   How much cooler depends on who you ask.   It's not my intention to be argumentative.  Patience is appreciated in advance.   

[LANCECASPER]

36 minutes ago, slowflyin said:

I agree and rarely run near 1600 TIT.  That being said, the lack of data is frustrating.   1750 didn't work so they dropped the TIT max to 1650.  Did 1650 not work?  I've read all I can find and haven't been able to find any remarks regarding 1650 burning up someone's exhaust.  Did your previous owner run 1650 as a limit?  @donkaye has more experience with the Bravo than most and he runs very conservative TIT temps.  He's still doing exhaust work mid-time.  If he had used 1625 or 1650 would he have had a different outcome?  One thread had comments from a gent that had a background in metallurgy, and he was fairly adamant 1650 was good to go.   Wonder how his exhaust is holding up.   In the end, all I can find is these engines need exhaust work, 1750 is bad, 1650 is Mooney's opinion, everyone else seems to lean toward some degree of cooler is better.   How much cooler depends on who you ask.   It's not my intention to be argumentative.  Patience is appreciated in advance.   

I believe @donkaye plans on a turbo at mid-time, but I don't recall him doing exhaust work mid-time. I could be wrong.

[Jetpilot86]

It’s why I’m asking the question?  @donkaye implies with his TIT setting He’s running 100-125° Lean of 1750 as his basis, 25° rich of a 1650° basis. While @LANCECASPER makes good points, you’re not really looking at the question I’m asking. The 53 combo number is roughly 78% based on stuff I’ve seen from @donkaye and @DVA. So does that mean the way @donkaye is running his is in the middle of the Red Box, I doubt it. If not and at 1600-1625 he’s 100-125° RO1750, what is driving people down to 1550° or 200°RO1750°. What I haven’t seen is a rich of peak TIT discussion similar to rich of peak EGT discussion for NA’s which is the most “similar” way to lean. Since the Aircraft Engine Operating clinic uses a turbo as cranky as ours, I’m really interested to see what they are leaning off of, a fixed temp, as we seem to be, or finding a peak TIT/EGT and working off of that. 
I guess what I’m asking is to see the “work” that got to the group answers. Whether you agree with @DVA, he was free with his references. Same with the old Mooney Test Pilot? Who swore you ran everything 50° ROP. 
Mooney hasn't helped by they way they’ve revised/not really revised how to operate the engine seemingly making all of us test pilots. 

[Jetpilot86]

1 hour ago, Shadrach said:

Do all of the Bravos need GAMIs to run power settings on the lean side?  
 

This thread interests me. It seems to me that TIT redline is more centered on Turbo longevity, not cylinder longevity. I see that everyone is advocating for using TIT to set power.  I understand why. On the rich side of peak, cylinder to cylinder power variation is minimal even with cylinder to cylinder mixture differences as much as 50-150 degrees from peak.  However, in a perfect world, would it not be better to be aware of both EGT and TIT? Would it not be better to set power with EGT as long as the setting results in a reasonable TIT number.

You are seeing what I’m getting at. From my studies mostly here, there are multiple AND competing/conflicting limits that very likely vary depending on your %HP at that moment. 
Going through all the old papers on my new toy as well last night, it seems the turbo and a couple of cylinders were done around 1500 hours. This on the original engine. Unfortunately, I don’t have the original Engine log to see how the previous, and only owner faired in the 1900TT he had on the plane, or how he operated it, but it seems like he faired better than most on here and certainly better than the other Bravo I’d looked at that went through 3 cylinders in 700 SMOH. With the FOH that came from Lycoming, both the turbo and exhaust are new, and obviously I’m trying to figure out how to get the most out of them without destroying them  

At the end of the day, I’m not as much interested in how someone operates their engine as much as why. Book? Old wives tales? A bunch of technical research? The advanced engine seminars?

[Fly Boomer]

27 minutes ago, Jetpilot86 said:

with his TIT setting He’s running 100-125° Lean of 1750 as his basis, 25° rich of a 1650° basis

Just to focus on the terms for a second, ROP and LOP are based on the EGTs for all cylinders being either rich or lean of peak respectively -- each cylinder can experience peak EGT at a different mixture.  Once familiar with a particular engine attached to a particular airplane, TIT can be used to get close to the target mixture, but TIT is not the metric.

[slowflyin]

48 minutes ago, LANCECASPER said:

I believe @donkaye plans on a turbo at mid-time, but I don't recall him doing exhaust work mid-time. I could be wrong.

I recall risers and wastegates on his first two engines.  Maybe @donkaye can chime in.  It's likely I may be mistaken.   Memory isn't what it once was.  

[Shadrach]

33 minutes ago, Jetpilot86 said:

You are seeing what I’m getting at. From my studies mostly here, there are multiple AND competing/conflicting limits that very likely vary depending on your %HP at that moment. 
Going through all the old papers on my new toy as well last night, it seems the turbo and a couple of cylinders were done around 1500 hours. This on the original engine. Unfortunately, I don’t have the original Engine log to see how the previous, and only owner faired in the 1900TT he had on the plane, or how he operated it, but it seems like he faired better than most on here and certainly better than the other Bravo I’d looked at that went through 3 cylinders in 700 SMOH. With the FOH that came from Lycoming, both the turbo and exhaust are new, and obviously I’m trying to figure out how to get the most out of them without destroying them  

At the end of the day, I’m not as much interested in how someone operates their engine as much as why. Book? Old wives tales? A bunch of technical research? The advanced engine seminars?

So it reads to me like you need to find your GAMI spread as a starting point. You stated before that the engine gets rough well before TIT redline. Does your  TIT peak and drop off before roughness? I’m sure Paul will be a great resource.

[Rick Junkin]

8 hours ago, Jetpilot86 said:

This implies to me that the peak TIT He’s richening FROM is 1750. Yet, I’ve seen quite a few others talk about leaning to 1550°, or 100°RO 1650°, or 200°RO the TIT Limit. Confused yet? I sure am.

I think you may be mixing apples and oranges just a bit here. My apologies up front if I'm pointing out things that are already obvious to you.

1750 TIT and 1650 TIT are redline limits for continuous operation; 1750 from the M20M POH and 1650 from the Lycoming Engine Operating Manual. It appears you are equating these limits with peak TIT, which is most likely not the case at a given power setting and flight condition. For instance on my last flight at 6,000', 30"/2200 RPM my peak TIT was 1665 and I ran at 13.4 GPH and 1615 TIT, 50 degrees LOP. If I chose to run ROP I would be running 100-150 ROP at a maximum TIT of 1565, and more probably closer to 1515, and about 16.5-18.0 GPH. At higher altitudes and/or different power settings the peak TIT would be different. The actual peak TIT, not the redline limit TIT, is the basis for setting your fuel flow to give you the desired TIT delta whether you're running ROP or LOP. The actual peak TIT may be above the redline TIT.

In my case I also monitor the individual EGTs to make sure the individual cylinders are LOP by at least 35 degrees for my nominal power settings. If they aren't I've got some adjusting to do.

As to the how and why of my engine management, it's derived from the same research you've been doing and applying all that I've learned from it. Attentiveness to mag health and timing, plug wires, fine wire plugs, a GAMI spread under 0.5, and lots of patience refining the power and fuel flow settings to arrive at what works for my engine.

6 hours ago, slowflyin said:

Mine doesn't require GAMIs.  It will run smooth on the lean side.  My biggest challenge with LOP ops is keeping the TIT in an acceptable range.  14.2 GPH-LOP puts TIT at or above 1650.  I can lean to 13.2 GPH, 1625 TIT without roughness or surging for around a 10 kt penalty.   I'd like to see 1600 or less.   LOP, my highest CHT drops from 385 to 350.  I'm constantly contemplating whether I should baby the jugs or the exhaust.    

I run the same fuel flow references for 75% and 70% power with similar, slightly cooler TIT results. In the mid teens I see TIT 40 LOP right at 1600. My CHTs at 13.2-13.4 GPH sit at 335-350, also in line with your engine. I can run smoothly at 30"/2200 RPM down to less than 11 GPH where power drops lower than is useful. I have GAMIs and they may help with that, but I don't have comparative data from the stock injectors.

Cheers,
Rick

[Fritz1]

We just did an annual on my Bravo, 750h on the factory reman, I run 2300/30" in cruise, 110 dF ROP on first EGT to peak, TIT typically 1580 dF, 18-18.5 GPH, power reductions not to exceed 2"/Min, typically 15dF CHT reduction per minute, gamis 0.3 gph spread, cylinders all 75-76, engine appears quite happy, my A&P said keep doing what you are doing, keep fingers crossed!

[Jetpilot86]

4 hours ago, Shadrach said:

So it reads to me like you need to find your GAMI spread as a starting point. You stated before that the engine gets rough well before TIT redline. Does your  TIT peak and drop off before roughness? I’m sure Paul will be a great resource.

Been working on organizing the AOM/AFMS's/337's/8710's & ICA's today.

Weather permitting after the new Battery, and Prometheus Recog/Taxi/Landing Light installs tomorrow, the the plan is to work on the engine break in some more and figure out the GAMI spread on what I have now, and get a first look at the G2 data, all as an excuse to go build more Time in Type.   I'll look closer at the reactions you asked about tomorrow as all the power setting reading I've been doing is helping me set up a plan to sort out how I intend to run the "will it make TBO" gauntlet of the Bravo.

Finally got the IFD's talking to the G600, figured out the fuel tank calibration of the Shadin Mini so it's time to confirm the KFC150 will still couple to various approaches. Which by the way is a pitch to NOT get an STEC like the one in the G1000 Bravo I got the Insurance sign off it.  You had to disconnect it at the FAF....  What good is that????   /pampered Cat3c Airline Pilot

I signed up for some of the Savvy consulting services and guess who is my rep......

[Jetpilot86]

56 minutes ago, Fritz1 said:

We just did an annual on my Bravo, 750h on the factory reman, I run 2300/30" in cruise, 110 dF ROP on first EGT to peak, TIT typically 1580 dF, 18-18.5 GPH, power reductions not to exceed 2"/Min, typically 15dF CHT reduction per minute, gamis 0.3 gph spread, cylinders all 75-76, engine appears quite happy, my A&P said keep doing what you are doing, keep fingers crossed!

I'm curious if you/anyone knows what the max over squared the Bravo's can be run?  My Checkout instructor was a big fan of 2300 as the RPM, especially in the pattern as he said it was an RPM you could use, firewall the MP and not break the engine if you forgot to push the prop in down final.  I need to ask him where he found/heard that number.

[Jetpilot86]

2 hours ago, Rick Junkin said:

I think you may be mixing apples and oranges just a bit here. My apologies up front if I'm pointing out things that are already obvious to you.

1750 TIT and 1650 TIT are redline limits for continuous operation; 1750 from the M20M POH and 1650 from the Lycoming Engine Operating Manual. It appears you are equating these limits with peak TIT, which is most likely not the case at a given power setting and flight condition. For instance on my last flight at 6,000', 30"/2200 RPM my peak TIT was 1665 and I ran at 13.4 GPH and 1615 TIT, 50 degrees LOP. If I chose to run ROP I would be running 100-150 ROP at a maximum TIT of 1565, and more probably closer to 1515, and about 16.5-18.0 GPH. At higher altitudes and/or different power settings the peak TIT would be different. The actual peak TIT, not the redline limit TIT, is the basis for setting your fuel flow to give you the desired TIT delta whether you're running ROP or LOP. The actual peak TIT may be above the redline TIT.

In my case I also monitor the individual EGTs to make sure the individual cylinders are LOP by at least 35 degrees for my nominal power settings. If they aren't I've got some adjusting to do.

As to the how and why of my engine management, it's derived from the same research you've been doing and applying all that I've learned from it. Attentiveness to mag timing, plug wires, fine wire plugs, a GAMI spread under 0.5, and lots of patience refining the power and fuel flow settings to arrive at what works for my engine.

I run the same fuel flow references for 75% and 70% power with similar, slightly cooler TIT results. In the mid teens I see TIT 40 LOP right at 1600. My CHTs at 13.2-13.4 GPH sit at 335-350, also in line with your engine. I can run smoothly at 30"/2200 RPM down to less than 11 GPH where power drops lower than is useful. I have GAMIs and they may help with that, but I don't have comparative data from the stock injectors.

Cheers,
Rick

Thanks for sharing the numbers, and the rationale, everyone, incase I missed someone. 

I'd been considering that those fruits are getting mixed, one of the reasons I'm seeking some clarity.  I recall the G1000 Bravo's Engine Monitor, I used for the insurance checkout, would do a TIT lean.  I leaned to a bit rich of 1650 TIT, mostly cross referenced that the CHT's were in line, and effectively ignored EGT.  With what I've seen from research, I very well could have been in the Red Box all the time since I never really was paying attention to what the EGT's were saying during the TIT lean process.  The airplane wasn't talking, so probably not....

The Insight 602 that was in my plane until yesterday didn't show TIT, but would lean EGT's, so I've been setting Power, Prop, then setting Mixture for the visor TIT and a few twists Rich, cross referencing the CHT's to make sure they are inline, but again, completely ignoring EGT, much less leaning for one.  I'm hoping the G2 will be easier to read from across the cockpit than the 602 was.  It appears that the new G2 will only lean EGT's, but since I don't have the TIT hooked up there for now, using the OEM gauge instead, it's moot.  What your post has caused me to wonder is if you could/should lean for EGT, either ROP or LOP, ensuring that TIT and CHT look appropriate for that MP/RPM/FF, or if the TIT is the egg, and the rest the chickens?  At the end of the day, it appears it's going to be a dance to find settings that keep them all where they need to be for longevity while keeping K's up and the FF down, especially since the overwhelming opinions here are that the POH and the same Visor Numbers are too aggressive for the Turbo/Cylinders, the reason I'm seeking to understand the stuff that I'm guessing I'll learn when I finish that Power Management course online.

It will be good to log some time dedicated specifically to this vs doing it on the way somewhere while fighting why the Avidyne's and the G600 weren't playing well together.  Pro tip, make sure the data speeds on your PFD/ND are the same as your GPS/COMS.  Apparently it didn't matter with the 430/530 it came with, as they were set to different speeds and it worked just fine, but with the Avidyne's on the same slow setting and the G600 expecting Fast because of it's setting, navigating direct anywhere was always 360 degrees, and the winds aloft weren't working.  The course points correctly now, tomorrow I hope to see if the winds are fixed as well.  Must have all my toys working!

[Jetpilot86]

7 hours ago, Shadrach said:

Do all of the Bravos need GAMIs to run power settings on the lean side?  
 

This thread interests me. It seems to me that TIT redline is more centered on Turbo longevity, not cylinder longevity. I see that everyone is advocating for using TIT to set power.  I understand why. On the rich side of peak, cylinder to cylinder power variation is minimal even with cylinder to cylinder mixture differences as much as 50-150 degrees from peak.  However, in a perfect world, would it not be better to be aware of both EGT and TIT? Would it not be better to set power with EGT as long as the setting results in a reasonable TIT number.

I'm really wondering if you are onto something.  At the end of the day the 1550 or 1600, or 1625 TIT numbers may end up keeping the CHT/EGT numbers in line, but especially at the high power settings for cruise the Bravo's can, and naturally I'd like to run, unless I'm leaning for the appropriate EGT, how is leaning off of TIT telling me where I am in relation to the RED BOX?  From what I've seen on power management from the online course so far, and from the manufacturers videos and Savvy, the name of the game is to stay out of the RED BOX.  Unless I haven't found the TIT method to manage the Red Box yet, it seems for sure the turbo way should work the same as the NA way to stay out of the RED BOX.

[Rick Junkin]

56 minutes ago, Jetpilot86 said:

What your post has caused me to wonder is if you could/should lean for EGT, either ROP or LOP, ensuring that TIT and CHT look appropriate for that MP/RPM/FF, or if the TIT is the egg, and the rest the chickens?

Per the Lycoming documents, TIT is the egg. My M20M TLS originally didn't even have an EGT gauge, only TIT and a single CHT on #5. We tend to over-think it because we have the ability to monitor everything with our modern engine monitors.

You've mentioned the Red Box so I'm assuming you're familiar with Mike Busch's preaching. He emphasizes keeping CHTs well below redline as a proxy for inter cylinder pressure indication, and using observed variations in EGT and CHT to identify developing engine anomalies before they become engine failures. In his recent webinars he states he doesn't even know how far LOP he is running, because he never checks to see what his peak EGT/TIT is. He pulls the mixture back to his known LOP fuel flow or until he feels a power drop, indicating he's LOP, and then leans further to make his fuel at destination what he wants it to be. Pretty simple once you have that all worked out.

What Paul @kortopates  will advise you is if you want to find peak TIT, do the "big mixture pull" to get straight to lean of peak and then enrich the mixture to approach the peak from the lean side. Once you observe the peak, make your FF adjustment to either ROP or LOP. This avoids dwelling in the red box/fin. Mike Busch will tell you there is no reason to do that, just stay LOP with your CHTs under control and your TIT below redline.

But you have said you want to operate ROP, so the above is a better method of getting there. After finding the peak TIT set the TIT where you want it to be with FF, and then you can crosscheck the CHTs and EGTs to monitor for the details of any changes in engine operation. I do the same thing, only on the LOP side. I use the "Lean Assist" mode on my G3X to mark the peaks on all six EGTs and then I can see at a glance if any of them have moved. But I don't fly with that page up all the time. My primary references are the TIT and the hottest CHT. If those are where I want them, I am confident everything is running as desired.

You mentioned you've digested the writings of DVA, Don Kaye and others so I'm not going to repeat any of that stuff. All the information you need about key numbers, % power, preferred power settings, LOP fuel flows etc. are in those writings.

And you're right, dedicating some air time to a practice area and familiarizing yourself with how all this works is the best way to learn it, especially if you can fly with someone experienced in managing this engine and can show you the whole gamut of power settings available to you.

Cheers,
Rick

[donkaye]

So much nonsense and over thinking in my opinion!  How do you get any flying done?  I've flown my plane, as of today 4,125.38 hours and am on my 3rd engine.  As mentioned before, my 1st engine went to 2,295 hours after the Bravo conversion at 1,300 hours.  The second engine had 1,600 hours on it and would have made it to TBO were it not for a shop incident.  In the interest of saving over $50,000 I decided to replace the engine at that time rather than doing a tear down and still having to replace that engine about 3 years later based on my flying time per year.  As mentioned previously, at mid time I needed to overhaul both the turbo and waste gate on both engines.  I  had exhaust work done on both engines.  The exhaust is the weakest part of that engine.  Now I lean to TIT of just under 1600 and confirm FF of 17.5 to 18.3 depending of time aloft with 18.3 being the 1st hour and 17.5 thereafter. Even GAMI's George Braly couldn't explain the difference.

Be my guest if you want to tax your brain with any deeper thought about how to lean this engine.  This is how I've run my engines for the past 31 years that I've owned my plane.  BTW I don't run my engine LOP.  Even with a GAMi spread of .3 neither I nor my usual passenger likes the occasional roughness or the speed reduction.

[Rick Junkin]

12 minutes ago, donkaye said:

As mentioned before, my 1st engine went to 2,295 hours after the Bravo conversion at 1,300 hours.

Don, I know I've read it in  a number of your previous posts but I can't recall - what drove your decision to overhaul at 2,295 hours?

Cheers,
Rick