M20M LOP Discussion

[DVA]

Hi!

I hope this will help other Bravo owners who struggle to run the TIO-540-AF1B at Peak or LOP TIT.  But first, in full disclosure I am not an A&P and this is not advice. I am simply illustrating my experience with this engine, and it or may not apply to you. Always follow the POH when you are not sure that your deviation from that document is in your best interest.

I am a lean of peak fan, always have been. It comes back from my days of working on non-aircraft internal combustion engines and proving that an engine run LOP operates cooler, cleaner and lasts longer than a similar engine run ROP.  I have taken the Advanced Pilots Seminar course on advanced engine management http://www.advancedpilot.com and had numerous discussions with Lycoming engineers, the folks at GAMI and engine builders, and I have used this knowledge to come to a few conclusions about this engine that I would like to share. I am not poking the sleeping “ROP vs LOP” dog. :-) and I realize that Lycoming - in some instances but not all - does not recommend operating LOP.  I also believe that if they could, they would revise that language to say:

If you have a good engine monitor, tuned injectors, and a knowledge of how your engine operates, you should run LOP whenever your heart desires - except on take off.

My opinion is that Mooney, when they introduced the TLS, continued their fine mission to make the fastest commercial SE piston airplane. To do this, they needed a lot of power -and- in a weight package that would not cause the flight envelope of the long body to get too forward on the CG, the TIO-540 was the answer. Bravo owners know that the airplane is already pushed forward CG and many have Charlie weight for aft ballast installed (which lowers the already skinny useful load). The TIO-540 is a complex high performance engine and should not be grouped with most other ground boosted engines for performance discussions,  The reasons for this, IMHO, are due in part to two things: 1) a complicated (but effective) turbocharging controller system, and 2) the requirement that the engine runs at very high percentage of power levels to make book speeds. I did a post a few weeks ago on the Bravo’s power percentage here.

Because this engine is normally operated at greater than 80% power during cruise by most people, this engine is very working hard and making a lot of heat for a lot of the time. It is also doing so with rather loose factory tolerances on the precision of fuel flow to the cylinders which makes it extremely difficult to run this engine in an wide and efficient range of power settings.

The POH states only two settings: 1) ROP TIT by at least 125dF for “best power"; and 2) Peak TIT as long it’s below 1750dF (1650dF at high altitudes) for “best economy" - the latter is sometimes impossible to achieve with this engine at higher power levels (30” MAP and above) because of poor fuel distribution which causes engine roughness. When near peak TIT (or EGT) the roughness is normally due to some cylinders running leaner than others. The leaner cylinders produce less power than do the richer cylinders which give you the impression that there is something wrong because you feel that power imbalance as roughness. (Note: that slight roughness is not a bad thing, your engine won’t fly apart, it really doesn’t care, only you do.) Spark plugs play a key role in this too - more on that in a bit.

Here’s the rub... Because most of the TIO-540-AF1Bs have unequal cylinder fuel distribution, when Bravo owners try to run the engine per the Sun Visor chart at Best Economy (Peak TIT) they may find an disconserting “roughness” and feel a slight loss of power.  That combo causes some consternation, and when that happens, some operators I’ve spoken with will simply dial the Bravo’s red knob in just a little richer and go slightly rich of peak TIT just enough to cure the roughness. Thinking that they are now 'just fine’ they fly the engine at that setting - when in fact they are not “just fine." They are now operating the engine “slightly ROP TIT” at a mixture setting that causes the most cylinder head heat, the highest internal combustion pressures and at a place where the engine can easily begin to exhibit detonation. (See graph below, which was taken from the Lycoming Flyer publication) The Mooney POH does not say it is OK to run the engine “slightly” ROP TIT because both the factory and Lycoming know that is a very bad mixture setting.  All of the experts I’ve spoken to agree that no internal combustion engine should be operated “slightly” (10-60dF) rich of peak. If you can’t make Peak TIT for whatever reason, better to just go greater than 80-100dF and accept the extra fuel costs and keep things in the engine cooler and happier.

I have not found anyone who disagrees that sustained high heat weakens, fatigues and shortens the life of the metals used in engines, and that’s why we see all kinds of advice about keeping cylinder head temps below 400dF. The Bravo’s POH advises that you use a combination of gauges when setting power - TIT and CHT as the most prominent. The POH also says that the CHT redline for this engine is 500dF - which everyone (experts or not) agrees is simply ridicules.

If you have an older Bravo, and especially one where a field AF1A to AF1B conversation was done, you may want to check to see on which cylinder the panel’s CHT temp probe is located. The AF1A probe was located on cylinder #5, and Mooney Service Instruction M20-101C states that it should be on cylinder #3 for the AF1B. Check yours, especially if you rely on the single panel CHT gauge, I’ve spoken to three Bravo owners where the CHT probe was still on #5 (mine was too). There is a big difference in the cooling between #3 and #5 - #3 being as much as 50dF hotter.

That all said, in summary the TIO-540-AF1B is a hot running, high power, high performance engine, different from many others. In the M20M it is asked to operate at the top of its performance range in order to make POH (book) performance numbers, and us Mooney drivers like to go fast! Adjusting the mixture on this engine can be  tricky due to engine’s generally unequal cylinder fuel distribution and, in many cases, the wrong type of spark plug being used.

I wanted my Bravo to act like most other well-tuned and instrumented airplanes I’ve flown. While always keeping the cylinder head temps below 400dF, I want to be able to safely set the engine for maximum power when I want to go fast, and I want the ability to safely save fuel when fast doesn’t matter as much. I don’t want complicated instructions to do this, and I want to feel as if the engine is happy and smooth no matter what.  Before I started this trek, I could not run my Bravo at Peak TIT at MAP higher then 29” without noticeable roughness and/or what I felt was unacceptable power loss. And there was no way this engine would run LOP.  I would flow about 22 GPH of fuel in cruise at 100dF ROP TIT (on hot days I needed to to be richer to keep the CHTs below 400dF).

Here’s what I did.

• I first ensured that magneto timing was correct. This is very important with high performance engines; you can often get away with inexact timing on lower power engines, but never on engines like the TIO-540. Mine were pretty close, but not exact - they are now. I had new Champion massive plugs installed about a hundred hours earlier, on inspection they looked okay and they passed the tester test. We gapped them at .016.
• I installed a new set of GAMI TurboInjectors. When I spoke with the factory rep John-Paul he cautioned me that this engine was a hard tune and that I should expect to have to work at, and that there might not be the success that others have with GAMIs on other engines. I love honesty - these guys at GAMI are true pros. 
• The first set of injectors made a marked and clear difference. I was able to run at Peak TIT smoothly for the first time, but I was unable to run LOP without roughness. I did a GAMI lean spread test and found that my spread was about 1.4GPH, while better, it was not ideal. I contacted the factory and John-Paul immediately sent out two replacement injectors for a better match. After that a test flight or two it showed that I actually picked up about two knots at peak TIT and fuel flow was down a little. I could now get a little bit LOP with a GAMI spread of .9GPH.  Also noticed CHT were generally cooler by about 20dF. This was due to the fact that the better fuel distribution was allowing all cylinders to run more equally, so at Peak TIT all cylinders were closer to their peak EGT. Fuel was saved for the same reason - unnecessary rich cylinders were now leaner for any given mixture setting.
• Because this engine seems finicky at different MAP/RPM settings, I decide to tune to a specific sweet-spot for the GAMI spread - I picked 29”/2400 for this as it is, according to the Lycoming power graphs, about 75% power on a standard day, at mid altitudes. This might have been the most important step I took in achieving success with this tune, on this engine to allow for good LOP performance.
• I sent the new GAMI lean test to John-Paul - not satisfied he sent me a single replacement for the one cylinder that was off a bit. (no charge for all of this and no questions asked). We installed that one injector and then did a test flight. The biggest change was that I could get more LOP without roughness, at 2400/29” I could get to about 20dF LOP. I would lose about 9 knots, but I was able to save almost 6 GPH of fuel. While I still couldn't get much past Peak TIT at higher power setting I was happy with the trade off; now I could achieve both fast and efficient settings. My GAMI lean spread was now a very comfortable .3GPH as you can see from the graph below. I thought that was all I needed to do but it wasn’t ...
• I have a Savvy Aviator account, I upload my JPI engine analyses data there, and I happily buy their yearly analysis service. I uploaded a flight and was looking at the graph and saw something on one of my lean spread tests that I could not understand. During a lean test, you should see all EGTs rise as you get leaner and leaner, then they should all peak (at slightly different times, that’s the fuel flow “spread”) and then they should drop off. On my test, there was a second peak? I submitted the flight for review at Savvy and Paul Kortopates wrote back and explained it, and as soon as I read his explanation I understood: He said "That second "peak" is actually what happens when the mixture goes lean enough to fire only one plug. You are seeing the same rise we would see if you switched off one of the magneto's so that there was only one plug firing- which is what we're seeing here. On one plug alone, combustion is slowed and therefore when the exhaust valve opens we are seeing more of the combustion event and the associated higher EGT because of it”  That’s when we discussed the last step I needed to take to get this whole project right - new plugs - but specifically fine wire plugs. It seems as if the fine wire plugs work better than the massives in two instances 1) older wet and oily engines (not the case here) and; 2) in lean mixtures. They’re expensive, about $80 a shot, but they also are suppose to last hundreds of hours longer.
• After researching both Champion and Tempest, I opted for the Tempest Fine Wires and installed 12 of them. Paul was right on! From the moment I turned the key I could tell that something was different. The engine started better and ran smoother on the ground and in the air, and I am now able to run LOP at 32” MAP and below if I chose. My CHTs are generally 30dF cooler than when I started this project, and I am saving fuel at every power setting. Where I use to run 22GPH at 2400/32 ROP, I now run 20GPH with the same airspeed, and if I want to throttle back to 2400/29, I loose about 10 knots and run about 15GPH at about 20dF LOP. 

In all, I have about $2500 invested here, but in fuel savings alone that will pay back in short order and then keep paying back. The big benefit is that I have more power options now with the aircraft and my engine will be much cleaner with less carbon deposits on the heads, the values, the plugs and the exhaust system. 

My flight profiles are not religious LOP, and yours don’t have to be either to get a benefit from the cleaning and cooling aspects of running your engine with a proper mixture, which, for me includes LOP at times. Typically I will run lower power and LOP in tail winds of any speed, because why not? If I loose 10 knots true in LOP but I make up some or all with a tail wind, I’m saving 5-6GPH of fuel AND cleaning the engine as I go.

Thanks for reading! I attached some pics - happy to try to answer any questions.

Dave

 

Edited June 20, 2016 by DVA

[KSMooniac]

Nice work! As soon as I read "champion massives" I would've bet you were going to have trouble...and I'm not surprised tempest fines helped you solve the problem. You're in rare company being able to operate an M LOP...congrats!

Sent from my VS985 4G using Tapatalk

[carusoam]

It is nice to see the shared details...

The LOP challenge is based on three prongs

1) Even FF to each cylinder.  The APS guys are as good as it gets. The GAMI spread test has nearly brought LOP to the masses...

2) Fine wire plugs that operate (Non Champion plugs) with properly timed mags.  Getting the non-working plugs out has been helpful for many.

3) Even air flow to each cylinder.  This one is an open item for the Lycoming intake system.  It doesn't have the nice curvy pipes of a typical balanced intake.  The curvy tubes allow for even flows through a wider range of MPs.

Questions come to mind....

4) Are you seeing better balance of air flow that other Bravo owners have?

5) Are the fuel injectors matching the individual air flows that are present?  If yes, this may cause a different challenge when operating ROP. Do you see a funky GAMI spread when going ROP now?

6) How LOP can you go?  For comparison the NA IO550 with curvy balanced intake tubes can be leaned down near 90°F LOP before turning itself off, around 5k'. (Based on old memory). Few people want to operate this LOP unless exploring Carsen's speed ops.  It is a nice demonstration on what tuned intakes can do.

7) how do you describe °LOP with the Bravo, do you use EGT or TIT?

8) are you abiding by the usual 65% HP rule to generally avoid the red box?

9) I would want to be in the camp of getting high %HP with the most excess air running through the system for cool cylinders and turbine.

holy cow that's a lot of questions...

Keep collecting and sharing data,

-a-

[Awful_Charlie]

Well done for writing all that up DVA - I've been meaning to do something like that for a long time but never got round to it, as I'm another one firmly in the LOP camp.

Most of the pain you've been through has already been done by the previous owner (GAMIs and fine wires), all I had to do was work with JP to get the injectors tuned a bit more. My difference is now down to 0.5GPH or so, but at 1950hrs on the engine, I'll sit with this until overhaul now.

The fine wires plugs have been great - so far I've got just over 700hrs on them, and other than cleaning out the odd bit of crud, there's been little maintenance. They are a git to gap though, and I've broken one when doing it, I try to keep them at 15-18 thou (as in a 15 feeler gauge should be a go and a 18 a no-go) - a larger gap may work, but is harder on the mag. I try to avoid the grit blaster except as a last resort, with enough time running LOP they keep themselves clean (apart for the odd lump of lead that accumulates in the lower plugs), and grit blasting just makes the insulator rough and easier for stuff to stick to

The other thing I'm quite particular about is the mags: I've actually got two pairs now, so one set can be worked on without downtime, getting the e-gap correct before setting the timing and also keeping them clean internally - you need your mags in good shape to run LOP.

To Aarons questions:

4) and 5) I'll post some Savvy data later, but not sure I understand the question for 5
6) What do you measure LOP by - the first one to peak or the last? Due to my 0.5 GPH difference, about 90 sounds in the right sort of area
7) In flight, using the EDM Lean find mode, which looks for the last to peak
8) I normally use 30"/2200 which depending on how you work it out comes in about 75% on FF
9) That is LOP! But you have to abide by the CHT and TIT limits. Also if you go too far LOP, then the BSFC drops off so much you might as well run ROP

Edited June 20, 2016 by Awful_Charlie

[DVA]

9 hours ago, carusoam said:

Questions come to mind....

4) Are you seeing better balance of air flow that other Bravo owners have?

Probably not - there is nothing different about my intake plumbing, its all stock stuff.  I do have a Challenger Air Filter installed, but that won’t affect any individual cylinder intake over another. 

5) Are the fuel injectors matching the individual air flows that are present?  If yes, this may cause a different challenge when operating ROP. Do you see a funky GAMI spread when going ROP now?

The whole concept of the tuned injectors is to match the unique airflows of each cylinder, hence the reason why one injector will flow more or less than another and you have to have the right injector in the right cylinder. The airflow in the manifold will change with different MAPs and that can cause small airflow deviations to the individual cylinders essentially “de-tuning” the work, but the differences are normally tolerable. You can see this effect sometimes by doing a GAMI spread test at different MAPs. The key to tuning a finicky engine like the AF1B is to pick the RPM/MAP combo that you want to use the most when you run LOP and do all your GAMI spread tests and tuning at that setting. That might be the reason why I am getting better results than others.  I am willing to accept a small deviation elsewhere to make one setting as good as possible. I choose 2400/29” for app 75% power as my preferred LOP cruise and that’s where I see a GAMI spread of .2-.3GPH. I can run 10-15dF LOP at higher settings, up to about 31” but the spread goes to .4 to .5GPH in some cases - still much much better than stock.

At best power/adequate CHT mixtures (100-125df ROP) you are so far ROP that it doesn’t really matter if the GAMI spread is huge, so to answer your second part of the question, no - I have no issues running ROP after the tuning.

6) How LOP can you go?  For comparison the NA IO550 with curvy balanced intake tubes can be leaned down near 90°F LOP before turning itself off, around 5k'. (Based on old memory). Few people want to operate this LOP unless exploring Carsen's speed ops.  It is a nice demonstration on what tuned intakes can do.

At my tuned 2400/29 point I can go well past 50dF LOP but I don’t go that far, I usually go about 20dF LOP for a balance of fuel economy (app 15GPH), CHT temps with cowl flaps closed (~380dF) and airspeed (loss of ~10 KTAS depending on altitude)

7) how do you describe °LOP with the Bravo, do you use EGT or TIT?

TIT, but if you have a decent GAMI spread, your EGT’s will all peak at close to the same FF and will be coincident with peak TIT, so you could use either method for the lean. I don’t use EGT/TIT for the lean now that I have everything set; I just quickly pull back to a known fuel flow and monitor the JPI.

8) are you abiding by the usual 65% HP rule to generally avoid the red box?

This will be a little controversial but here goes: the short answer is, no and I can’t agree with the term “rule”.

The Red Box, IMHO, is overdone a bit on the lean side of peak. I am not challenging all the great work and knowledge of the team at GAMI, or Mike Busch and his vast knowledge, their collective work is industry changing and I respect and have learned from all of them. The Red Box is a cleaver way of showing real mixture danger zones, but mostly centered around middle of the red zone at a given RPM/MAP. As you go farther to the east or west of middle, these dangers become logrithmically less and less all things being equal. If you could draw the Red Box or Red Fin with a gradual fading out of the red to each side, instead of a hard stop, I think it would be easier to explain and use. But a hard stop is conservative way of presenting it and in these days of litigious stupidity I probably would do exactly that too.

There is no reason to fear detonation at any power level as long as you are in control of the combustion event, and I think all the guys at GAMI/Savvy would tend to agree with that. I feel I am in control of the combustion event at 75-80% power running LOP on this engine. My engine is in good condition, my timing is correct, I have a strong ignition system, my CHT’s are within acceptable limits, my fuel injection system is balanced, I have excellent engine monitoring with conservative alarming set, and I pay attention to the engine in flight. I can say that I am not in any danger whatsoever even though I may fall within the Red Box.

As a final thought, lets simply throw all of the hard work that Deakin, Braly, Atkinson, et al. have done proving to the world and the engine manufactures' that LOP is not a bad thing. Lycoming and Mooney both recommend and ask you as the pilot of M20M to run that engine at 80-90% power, in cruise, for hours, at Peak TIT. If that an OK place to be mixture-wise according to them, then its only reasonable to believe that **any** mixture setting LOP TIT has to be cooler and less prone to detonation - so why not be there?

 

Replies in-line, above.

Best regards
Dave

Edited June 20, 2016 by DVA

[carqwik]

You can't run (at least with my engine) at 80-90% power at peak TIT....you'd be way over the TIT limit of 1650 degrees for normal cruise at that power (likely 1700+).  IIRC, there is a one minute limit to run over 1650 TIT(not to exceed 1750) when setting up for cruise.  I run at 100-125 ROP with a max cruise at 30/2400.  More typically cruise at 27/2400 at 100 ROP.at 16.5 gph.

Congrats on getting your engine LOP...

[DVA]

Just now, carqwik said:

You can't run (at least with my engine) at 80-90% power at peak TIT....you'd be way over the TIT limit of 1650 degrees for normal cruise at that power (likely 1700+).  IIRC, there is a one minute limit to run over 1650 TIT(not to exceed 1750) when setting up for cruise.  I run at 100-125 ROP with a max cruise at 30/2400.  More typically cruise at 27/2400 at 100 ROP.at 16.5 gph.

Congrats on getting your engine LOP...

Hi Carqwik - at 30"/2400, according to the Lycoming Engine Manual, and interpolated here for convenience, you are at ~80% power. Per the POH, Max TIT on that engine is 1750dF continuous as long as other engine indicators are within limits and you are below FL220. Above FL220 max TIT is 1650dF. Going over either max TIT value during leaning is permissible for a short period.

%HP            HP        RPM        MP    Altitude 

93%            250        2400        34"    0-FL220

87%            235        2400        32"    0-FL230

80/85%    215-225    2400        30"    0-8K/8K-FL250

75/80%    200-220    2400        28"    0-8K/8K-FL250

65/70%    180-195    2400        26"    0-8K/8K-FL250

60/65%    160-180    2400        24"    0-8K/8K-FL250

55/60%    145-165    2400        22"    0-8K/8K-FL250

 

 

[carqwik]

Ok...well you can run yours as you see fit.  I'd bet your exhaust tubing won't last too long at those temps (continuous above 1650 TIT)...

[DVA]

Just now, carqwik said:

Ok...well you can run yours as you see fit.  I'd bet your exhaust tubing won't last too long at those temps (continuous above 1650 TIT)...

Just quoting the POH for accuracy, not recommending anything.

[N350ka]

Im new to the management of an engine like this and generally what i was told when I (two weeks ago) took instruction is keep the CHTs between 345-425 above 32" lean to 1650TIT and otherwise follow the chart. This conversation makes me question if I've been managing the engine correctly after having started flying on my own. Anyone have any advice (I know this isn't exactly on topic) I attached a few pictures of what I've had her set up for at cruise. These were taken between 10-20K 

[carusoam]

Welcome aboard, 350ka.

Best regards,

-a-

[LANCECASPER]

1 hour ago, N350ka said:

Im new to the management of an engine like this and generally what i was told when I (two weeks ago) took instruction is keep the CHTs between 345-425 above 32" lean to 1650TIT and otherwise follow the chart. This conversation makes me question if I've been managing the engine correctly after having started flying on my own. Anyone have any advice (I know this isn't exactly on topic) I attached a few pictures of what I've had her set up for at cruise. These were taken between 10-20K 

You would be wise to keep your CHT 400 or less and your TIT 1600 or less. This will be kind to your cylinders and your exhaust system.  

[N350ka]

2 hours ago, LANCECASPER said:

You would be wise to keep your CHT 400 or less and your TIT 1600 or less. This will be kind to your cylinders and your exhaust system.  

so how does one do that and get any performance out of the engine, seems to me that you'd end up not making any power at those kinds of temps if you're running ROP, I've never tried running LOP is there a way to run LOP get those temps and get any real performance outa the engine? 

[carqwik]

Forget about the performance metrics in the POH.  Run your engine in cruise according to the method of MP + (RPM/100) to get the key number.  For example, 29" plus 2400 rpm = 53.  I think that is what is the max cruise key number as to a power setting according to some Bravo experts.  (Someone else jump in if I'm not recalling this correctly.  I use 54 as my max cruise number....but typically cruise at 51).  Always at 100-125 ROP with CHTs below 400 and TIT around very low 1600s or so.    You'll get whatever performance is available at those settings.  Climb higher and you get more TAS.

 

[carusoam]

350ka,

Are you familiar with MAPA?

Are you familiar with the people related to GAMI?

These are two resources that many residents here go to for training.  MAPA is more Mooney flying.  GAMI is more engine management.

When you bought your Bravo, did you get transition training to go with it?

When you get a chance, update your avatar data to include where you call home...

we have a couple of CFIIs on board here that are good go to guys for Bravo operations.

It is OK to experiment with in the limits of the POH.  As somebody has pointed out above.... That can get expensive pretty quickly.  Some people have the means to swap out cylinders in order to go fast.  Others, preserve the cylinders as a priority and adjust the speed that they use.

DVA has done a nice job above detailing LOP for the Bravo.  Few people have been successful enough to write about.  Often it works out to 'been there, done that, and fly ROP...'

Generally speaking temps above 380°F are tougher on cylinder life.  TIT's above 1650°F are tough on turbine and exhaust parts.

One other thing to know about Bravo engines is the exhaust clamps have strict guidelines on re-use for safety reasons.

Maybe you got all this training and information.  I'm just going to err on the excess information side for the new guy here...

There is so much to know about the operations of a powerful XC Machine like the Bravo...

Want to tell us about yourself and what you were flying before the Bravo?

just trying to be helpful.  I'm not selling anything....

 

Best regard,

-a-

 

[N350ka]

10 hours ago, carusoam said:

350ka,

Are you familiar with MAPA?

Im familiar with them and a member!

Are you familiar with the people related to GAMI?

Not at all, I have a feeling given the many different management strategies involved in flying these things I should be. 

These are two resources that many residents here go to for training.  MAPA is more Mooney flying.  GAMI is more engine management.

When you bought your Bravo, did you get transition training to go with it?

Yes, I got 10 or so hours of transition training however I'm starting to realize it could have been more in depth.

When you get a chance, update your avatar data to include where you call home...

North Dakota! 

we have a couple of CFIIs on board here that are good go to guys for Bravo operations.

It is OK to experiment with in the limits of the POH.  As somebody has pointed out above.... That can get expensive pretty quickly.  Some people have the means to swap out cylinders in order to go fast.  Others, preserve the cylinders as a priority and adjust the speed that they use.

The nicer I can be to the engine the better, Thats always an opinion I've had if you take care of your equipment it'll take care of you. 

DVA has done a nice job above detailing LOP for the Bravo.  Few people have been successful enough to write about.  Often it works out to 'been there, done that, and fly ROP...'

Generally speaking temps above 380°F are tougher on cylinder life.  TIT's above 1650°F are tough on turbine and exhaust parts.

Good to know I'm going to change how I manage the engine. 

One other thing to know about Bravo engines is the exhaust clamps have strict guidelines on re-use for safety reasons.

Maybe you got all this training and information.  I'm just going to err on the excess information side for the new guy here...

Much of this I didn't hear, Including the above Exhaust clamp info. 

There is so much to know about the operations of a powerful XC Machine like the Bravo...

Want to tell us about yourself and what you were flying before the Bravo

DC-3's, Gooses, cessna's, pipers, most of the lower performance singles multis and helicopters. 

To be honest the big radial engines don't require management like this, or I was just given better instruction on their management. 

just trying to be helpful.  I'm not selling anything....

Thank you Im glad I spoke up Y'all are all very helpful! 

Best regard,

-a-

 

 

[DVA]

Greetings N350ka!

You’ll find all kinds of good advice here. One theme you will hear often is the advice to keep the CHT below 400dF. I know this contradicts the POH high limit of 500dF, but...

There is so much evidence and common metallurgy fact that heating up the cylinders and the heads past 400dF reduces their strength by nearly 50% and significantly decreases cylinder life. The folks at GAMI and their sister company Advanced Pilot have unarguably done more recent research on airplane engines than even the manufactures. If you were to take their course on engine management (online or in person) you would instantly change your habits on how you operate that bravo engine. Others may modify this slightly, but here is some common advice, especially on the AF1B engine:

1. Don’t let the CHT's go above 400dF in climb - reduce angle, power, open cowls, whatever it takes.
2. Shoot for CHT’s of less than 400dF in cruise. - Reduce power, run richer if ROP, run leaner if LOP (if able), open cowl flaps and sacrifice the few knots of air speed.
3. Install GAMI injectors and run Tempest Fine Wire plugs - just that alone will save you fuel under most any condition, help to balance out the heating of the cylinders and heads, and you might pick up a knot of two due to the more even fuel flow. If you’re careful with the tuning, you may be able to run LOP, accept the slight airspeed loss and save a lot of money. (I do)
4. Ensure that the V-clamps on the exhaust system around the turbo are in excellent shape as carusoam points out above. Replace them and the gaskets if not, torque to the proper settings and safety-wire them. Don’t be afraid of running the TIT up to the max of 1750 at the lower altitudes if you have to as long as CHT’s are below 400dF. The steel exhaust, the clamps and the turbo itself are designed to withstand these temps.  Borg-Warner did extensive research into inlet temperature and the effects on the metals and lubricating systems of turbos, and found that 970dC (1778dF) was a safe upper limit that had a reasonable amount of tolerance/spread for safety. That said, I would now add:
   1. Don’t run the AF1B at a level that produces that type of TIT for very long because you are likely either running at too high a continuous power for any kind of longevity, or your ignition timing and/or baffling is out of whack.
   2. Run at 1600-1650 all day and all night but watch where you detune to get there. In order to stay away from the high pressure, highest cylinder head temp region of the combustion cycle, you must go at least 80dF rich of ANY peak TIT at power settings above 70% or so. ( I did a post here on Bravo power settings) e.g. If you have a peak TIT of 1650df, don’t just richen a little to bring it down to say 1600, richen enough to bring it down to 1550 to stay away from the near-ROP region, known in some circles as the Red Box, Mike Busch has great article on this. 
   3. Don’t worry about empirical maximums of EGT and TIT as a first concern - Max CHT and Oil Temp trump them by a mile.
5. Last but not least - Mooney made the Bravo fast by pushing the Lycoming TIO-540-AF1A/B engine hard to make book numbers, that doesn’t mean we have to! If you back this engine down a little, fly a bit slower than the book, cool it down as a result, the 540 can make TBO and beyond, and more importantly can do it reliably.

Best of luck!
DVA

[LANCECASPER]

On the M model, the exhaust clamps which are over $500 each (Piper seems to be the least expensive source for that part number) have a maximum of two re-torques then they must be discarded. In the log books you should look to see if the exhaust was ever removed. If it was re-installed then you are on the last re-torque. If it comes off again it's time for a new one.

This is not a place to save money. When that clamp (the original ones were spot welded, the new ones are riveted) goes bad the 1600 degree exhaust consumes the firewall, the cabin and the occupants.

[Danb]

DVA beat me to the punch, treating your engines to nice temps will increase your odds on lower maintenance costs. You don't lose much by running your engine at 29-30 " max and 2400, I keep my tit close to 1600, chts generally under 380, still get good speeds on 17-18 gph. He has some good info on turbos a couple weeks ago a good read.

[N350ka]

Wow, thanks everyone for the responses! Im adding all of those to my list of things I should do to the plane. GAMI injectors Tempest Plugs and to make sure I don't get eaten by fire! Since I'm on the topic any maintenance items that would be good to keep around the hanger (spare bulbs, tires, etc.) other than oil of course. If y'all can't tell this is my first Mooney and first plane owned! Ive started running the engine much cooler since the last pictures I uploaded. Ive attached another picture, Any more tips guys? Sorry again I realize this is not the direction this thread was supposed to go! 

[carusoam]

0ka,

You ARE the reason MS exists...

Many people stumble in here looking for a single answer to find out there are questions they haven't even begun to think about...

One day you will have questions that more people will find current.

following that, you will be able answer questions based on your own experience.

Hang out long enough, you'll know more about the other Mooneys to help a new guy that arrives on board.

Speed, efficiency and safety never get old.

Even questions from the newest Mooney pilots get answers.

You are ahead of many people. Some pilots are still in the early days of having their Mooney find them...

Flying is some pretty serious business/avocation!

Keep up the learning and share some of what you know.

Post something in the today's flight thread.

Best regards,

-a-

[carusoam]

Part II...

Use the search box there are threads for tools people take with them...  

There are tools they use while flying, like portable O2 systems and related parts. Fire extinguishers, iPads and ADSB devices

Stuff they keep in the hangar for planned  Maintenance...  Tire's and oil and oil additives have gotten a lot of discussion.  Towels and drip protectors and cleaners when the protections fail...

Projects they are working on... Even books or apps they are writing....

A couple people have their own spare airframes.....

Keep in mind there are some interesting people that fly Moonies.

Best regards,

-a-

[donkaye, MCFI]

I've been flying and teaching in the M20M for nearly 24 years and am mid time on my second engine right now.  I have also taken the Advanced Pilot Course from GAMI.  I think Dave has given the best explanation and tips on how to best run the TIO540AF!B engine I have read to date.

Thanks, Dave, for your contribution.  You are a great addition to this Forum.

 

[DVA]

26 minutes ago, donkaye said:

I've been flying and teaching in the M20M for nearly 24 years and am mid time on my second engine right now.  I have also taken the Advanced Pilot Course from GAMI.  I think Dave has given the best explanation and tips on how to best run the TIO540AF!B engine I have read to date.

Thanks, Dave, for your contribution.  You are a great addition to this Forum.

 

It’s a Good Day when Don Kaye compliments you (thank goodness you’ve never seen me land the damn thing) Thank you sir!

[donkaye, MCFI]

1 hour ago, DVA said:

It’s a Good Day when Don Kaye compliments you (thank goodness you’ve never seen me land the damn thing) Thank you sir!

There's always my landing video in case you don't have it, but then again you're probably being too modest. ;-)