Turbo leaning via EGT

[donkaye]

19 minutes ago, Rick Junkin said:

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

Although I had ordered the engine previously, just before the change the density controller went out on the way back from Oshkosh.  The engine itself was running well, but I was doing a lot of instrument flying and was beginning to feel uncomfortable.  With a controller repair it probably could have gone on longer, just like Mike Bush with 5,000 hours on his engines, which I think were Lycoming TIO540s.

[Shadrach]

39 minutes ago, donkaye said:

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.

If you have a turbo that runs well on the lean side of peak, there should not be a speed reduction. Just an increase of a few inches of MP. There must be another limiting factor.

[LANCECASPER]

The Continental that I have in the Acclaim loves LOP and that engine/ prop combination is smooth as glass LOP. I prefer to fly it that way.

In three different Bravos, one of which had GAMIs, they never ran smooth enough LOP for my liking. GAMI will tell you that it is very hard to get this engine to run LOP smoothly. The intake is not as balanced which I believe is the major factor. 

[donkaye]

37 minutes ago, Shadrach said:

If you have a turbo that runs well on the lean side of peak, there should not be a speed reduction. Just an increase of a few inches of MP. There must be another limiting factor.

Yes, TIT.

[Rick Junkin]

16 minutes ago, Shadrach said:

If you have a turbo that runs well on the lean side of peak, there should not be a speed reduction. Just an increase of a few inches of MP. There must be another limiting factor.

A bit of thread creep - 

I have not taken the APS course yet, and this is something that still puzzles me about LOP ops. What I read from Savvy and hear in Mike's webinars says when operating LOP, the fuel flow solely determines the HP, and when ROP the MP and RPM determine the HP. Which I understand to mean that no matter what MP or RPM I'm running, as long as I'm lean of peak 13.2 GPH will yield 70% rated HP on my TIO-540-AF1B. And I can know I'm LOP by observing a decrease in power and airspeed when I pull the mixture back to my LOP fuel flow.

BUT, I've read other sources that say as Ross does, that I can regain that airspeed, and hence add power (increase HP) at that same 13.2 GPH, by increasing the MP after I'm LOP. That appears to be a contradiction to the "FF solely determines HP LOP" assertion. But that assertion has never fully made sense to me either.

Dang, I need to take that course.

Cheers,
Rick

[Danb]

I’m in the same camp as Lance although my Bravo ran LOP find it wasn’t worth the loss of speed nor  run with the tit above 1600, I couldn’t keep the temp under 1600 so that limited the LOP on the Bravo. I do run LOP on the Acclaim since apparently the continental runs better and supposedly lasts longer running LOP. I still have difficulty getting the settings set up properly while staying under 1600 in th Acclaim. I’m obviously not setting it up fast enough to stay out of harm’s way. Not sure of the best way to get to my cruise settings either using lean find or the big pull to the fuel flow or just guessing. 

[Shadrach]

48 minutes ago, Rick Junkin said:

A bit of thread creep - 

I have not taken the APS course yet, and this is something that still puzzles me about LOP ops. What I read from Savvy and hear in Mike's webinars says when operating LOP, the fuel flow solely determines the HP, and when ROP the MP and RPM determine the HP. Which I understand to mean that no matter what MP or RPM I'm running, as long as I'm lean of peak 13.2 GPH will yield 70% rated HP on my TIO-540-AF1B. And I can know I'm LOP by observing a decrease in power and airspeed when I pull the mixture back to my LOP fuel flow.

BUT, I've read other sources that say as Ross does, that I can regain that airspeed, and hence add power (increase HP) at that same 13.2 GPH, by increasing the MP after I'm LOP. That appears to be a contradiction to the "FF solely determines HP LOP" assertion. But that assertion has never fully made sense to me either.

Dang, I need to take that course.

Cheers,
Rick

When operating the engine at a mixture setting with a surplus of fuel (ROP), power is determined by mass air flow. This is because that surplus fuel is not being converted to power.  When operating at a mixture setting with a surplus of air, power can be determined by fuel flow because all of the fuel is being used to make power.

65% power is 65% power no matter which side of peak the engine is set. The problem is that it requires more manifold pressure to run 65% LOP than 65% ROP. That situation  is correctable  with a turbo. It is not correctable with a f normally aspirated engine once the throttle is wide open.

[kortopates]

BUT, I've read other sources that say as Ross does, that I can regain that airspeed, and hence add power (increase HP) at that same 13.2 GPH, by increasing the MP after I'm LOP

No, FF solely determines LOP power, but what Ross was referring to is with a Turbo you can lean with air, not just FF. So whatever FF you want to target too, set accodingly and then add air (MAP) without changing FF. But you will not gain airpseed by simply adding air, since power is dropping as you move further from peak and much more quickly on the LOP side than the ROP side.

[Fly Boomer]

5 hours ago, donkaye said:

With a controller repair it probably could have gone on longer, just like Mike Bush with 5,000 hours on his engines, which I think were Lycoming TIO540s.

TCM TSIO-520s.

[Fly Boomer]

4 hours ago, Rick Junkin said:

I can know I'm LOP by observing a decrease in power and airspeed when I pull the mixture back to my LOP fuel flow.

You can know you are LOP by observing that the EGT of all cylinders is on the lean side of peak.

[Rick Junkin]

2 hours ago, Fly Boomer said:

You can know you are LOP by observing that the EGT of all cylinders is on the lean side of peak.

The words I used were a paraphrased quote of Mike Busch in a webinar saying he never looks at EGT and knows he’s LOP when he feels the slight decrease in power as he pulls the mixture, and then leans more as needed to get to the CHT and fuel remaining at destination numbers he wants to see.

[Fly Boomer]

11 minutes ago, Rick Junkin said:

The words I used were a paraphrased quote of Mike Busch in a webinar saying he never looks at EGT and knows he’s LOP when he feels the slight decrease in power as he pulls the mixture, and then leans more as needed to get to the CHT and fuel remaining at destination numbers he wants to see.

I think I read that article or watched the video (whichever it was). 

Not trying to be snarky -- I just never know who has experience with LOP and who does not.

[Shadrach]

10 minutes ago, Rick Junkin said:

The words I used were a paraphrased quote of Mike Busch in a webinar saying he never looks at EGT and knows he’s LOP when he feels the slight decrease in power as he pulls the mixture, and then leans more as needed to get to the CHT and fuel remaining at destination numbers he wants to see.

I have a feeling that’s because he has verified his preferred FF settings are in his comfort zone with regards to the mixture spectrum. Sooo, it would be more fair to say he doesn’t bother to look EGT now. That does not mean that he never has.

 

[Rick Junkin]

4 hours ago, kortopates said:

7 hours ago, Rick Junkin said:

BUT, I've read other sources that say as Ross does, that I can regain that airspeed, and hence add power (increase HP) at that same 13.2 GPH, by increasing the MP after I'm LOP

No, FF solely determines LOP power, but what Ross was referring to is with a Turbo you can lean with air, not just FF. So whatever FF you want to target too, set accodingly and then add air (MAP) without changing FF. But you will not gain airpseed by simply adding air, since power is dropping as you move further from peak and much more quickly on the LOP side than the ROP side.

Ok, please bear with me for a question with a practical example. Here's how I normally cruise:

30"/2200 RPM
13.2 GPH
TIT at 1615 (40dF LOP)

Now the question -  I increase the MP to 32" and adjust the mixture to maintain 13.2 GPH. What happens to my airspeed? 

Thanks for your patience.

Cheers,
Rick

[kortopates]

You have to keep in mind Mike doesn’t fly over 65% except very rarely since he’s all about longevity and therefore has no red box to be concerned about. That’s why leaning by CHT works him as a proxy. Plus he knows his engine so well he knows how lean it is.


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[kortopates]

Ok, please bear with me for a question with a practical example. Here's how I normally cruise:
30"/2200 RPM
13.2 GPH
TIT at 1615 (40dF LOP)
Now the question -  I increase the MP to 32" and adjust the mixture to maintain 13.2 GPH. What happens to my airspeed? 
Thanks for your patience.
Cheers,
Rick

it depends are where you started relative to peak on the mixture curve.
But if per your example you started at 40F LOP, added 2”, all else the same, you’ll see a significant drop in IAS if that was 40F lop on your richest cyl. But a drop.


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[Rick Junkin]

7 minutes ago, Fly Boomer said:

I think I read that article or watched the video (whichever it was). 

Not trying to be snarky -- I just never know who has experience with LOP and who does not.

 

7 minutes ago, Shadrach said:

I have a feeling that’s because he has verified his preferred FF settings are in his comfort zone with regards to the mixture spectrum. Sooo, it would be more fair to say he doesn’t bother to look EGT now. That does not mean that he never has.

 

Understand, and agree.

I've done the same with my engine and just BMP to my desired fuel flow and crosscheck TIT and CHTs, and then look at the details occasionally inflight and always review the download data to spot any anomalies. Mike's webinar comment was in response to a question asking how many degrees LOP he runs, and his response was essentially "I honestly don't know and I don't care, and here's how I do it..."

But context is everything, so yes, anyone reading through this and looking to play with LOP needs to do the homework and understand what they're doing to the engine and how to do it safely.

Cheers,
Rick

[Jetpilot86]

9 hours ago, donkaye said:

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.

Here is an old quote of yours from 2012 that caught my eye and spawned my question quoting your post, above:

On 12/6/2023 at 12:24 PM, Jetpilot86 said:

  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%.

It's not easy, especially since it's been a few decades since I few GA, despite 12k hours since I last few GA.  At least now I know questions to ask vs my younger and dumber days.

By no means am I disputing your experience, which in the Bravo is orders of magnitude more than mine, but trying to understand where those numbers came from as a rookie with a freshly overhauled engine.  I picked it up with 10 SFOH.  It appears you've become even more conservative since your 2012 post, based on your reply here.  My question about the 2012 post is whether you were choosing the 1600-1625 TIT number as richened from a 1750, (100+ ROP), or some other peak value, or is it just a directly derived number from somewhere else?  If so please share the source.

I got out for a few short flights today, to test out my Insight G2 upgrade from the old 602 model, and setup cruise around the 5000' visor numbers.  At 30"/2200 & 13.9GPH, it just didn't want to run at 13.7gph, I was 10k under what the book said I should have been getting for TAS @ 5500'.  TIT was at 1560.  #3 was the hottest cylinder at 377 & #2 the coolest at 292.  I'm 99% sure the cowl flaps were closed, but they might have been at 1/2.  The EGT's were all at 1500.  It "felt" like I was LOP but the engine monitor wasn't giving me any indications that I'd even reached peak.  Going over at 27"/2200 and 12.3gph was also 10k under the chart with similar numbers as above.  From what I've learned about leaning so far, either something is off, or I was lean of peak today. <shrugs>  I've seen book speeds higher and tomorrow I hope to have time to make a few runs at 10k & 11k to gather those numbers out of the G2.

Thanks to everyone for the insights here, I'm not trying to re-invent the wheel, as much as I'm trying to understand how the Bravo wheel was invented since it appears the POH was never revised to reflect the updated Lycoming suggestions for engine longevity.  But I'm still reading....

Cheers,

[Shadrach]

1 hour ago, Rick Junkin said:

Ok, please bear with me for a question with a practical example. Here's how I normally cruise:

30"/2200 RPM
13.2 GPH
TIT at 1615 (40dF LOP)

Now the question -  I increase the MP to 32" and adjust the mixture to maintain 13.2 GPH. What happens to my airspeed? 

Thanks for your patience.

Cheers,
Rick

Why you do that? LOP to much leaner than peak?
We were talking about speed/power loss going from ROP to LOP.  
I don’t have a Bravo power chart in front of me but if I did, I could easily calculate the approximate LOP FF that would yield the same speed. Power would be the same, FF would be less and CHTs would likely be lower as well.  The down side is that TIT would be closer to redline.

[Shadrach]

16 minutes ago, Jetpilot86 said:

Here is an old quote of yours from 2012 that caught my eye and spawned my question quoting your post, above:

It's not easy, especially since it's been a few decades since I few GA, despite 12k hours since I last few GA.  At least now I know questions to ask vs my younger and dumber days.

By no means am I disputing your experience, which in the Bravo is orders of magnitude more than mine, but trying to understand where those numbers came from as a rookie with a freshly overhauled engine.  I picked it up with 10 SFOH.  It appears you've become even more conservative since your 2012 post, based on your reply here.  My question about the 2012 post is whether you were choosing the 1600-1625 TIT number as richened from a 1750, (100+ ROP), or some other peak value, or is it just a directly derived number from somewhere else?  If so please share the source.

I got out for a few short flights today, to test out my Insight G2 upgrade from the old 602 model, and setup cruise around the 5000' visor numbers.  At 30"/2200 & 13.9GPH, it just didn't want to run at 13.7gph, I was 10k under what the book said I should have been getting for TAS @ 5500'.  TIT was at 1560.  #3 was the hottest cylinder at 377 & #2 the coolest at 292.  I'm 99% sure the cowl flaps were closed, but they might have been at 1/2.  The EGT's were all at 1500.  It "felt" like I was LOP but the engine monitor wasn't giving me any indications that I'd even reached peak.  Going over at 27"/2200 and 12.3gph was also 10k under the chart with similar numbers as above.  From what I've learned about leaning so far, either something is off, or I was lean of peak today. <shrugs>  I've seen book speeds higher and tomorrow I hope to have time to make a few runs at 10k & 11k to gather those numbers out of the G2.

Thanks to everyone for the insights here, I'm not trying to re-invent the wheel, as much as I'm trying to understand how the Bravo wheel was invented since it appears the POH was never revised to reflect the updated Lycoming suggestions for engine longevity.  But I'm still reading....

Cheers,

That is a big CHT spread. Was it running smoothly? I have a hard time believing that an 85° delta is accounted for by cooling  airflow variance alone. Seems to me those cylinders were at significantly different power settings (FF). 

[Rick Junkin]

6 minutes ago, Shadrach said:

Why you do that? LOP to much leaner than peak?
We were talking about speed/power loss going from ROP to LOP.  
I don’t have a Bravo power chart in front of me but if I did, I could easily calculate the approximate LOP FF that would yield the same speed. Power would be the same, FF would be less and CHTs would likely be lower as well.  The down side is that TIT would be closer to redline.

Yeah I crossed the streams there, I was thinking about your previous post.

9 hours ago, Shadrach said:

If you have a turbo that runs well on the lean side of peak, there should not be a speed reduction. Just an increase of a few inches of MP. There must be another limiting factor.

I set the cruise power settings I noted in the post above, and I don't increase the MP. 30/2200, 13.2 GPH yields TIT 40d LOP at 1615d.

Cheers,
Rick

[Rick Junkin]

34 minutes ago, Jetpilot86 said:

#3 was the hottest cylinder at 377 & #2 the coolest at 292.

 

15 minutes ago, Shadrach said:

That is a big CHT spread. Was it running smoothly? I have a hard time believing that an 85° delta is accounted for by cooling  airflow variance alone. Seems to me those cylinders were at significantly different power settings (FF). 

@Jetpilot86 I'm guessing you have the OEM CHT probe with an added piggy-back or washer thermocouple going to your Insight monitor from one of those cylinders and it's giving you inaccurate data on your Insight. What were the other 4 CHTs? I had that setup with a JPI EDM 830 and #5 had the OEM CHT probe with a JPI piggy-back and never did indicate correctly on the JPI. I think I've read that some of the Bravos had the OEM CHT on #3, and if that's the case and you have a washer CHT thermocouple that could explain the majority of the difference.

Cheers,
Rick

[Shadrach]

19 minutes ago, Rick Junkin said:

Yeah I crossed the streams there, I was thinking about your previous post.

I set the cruise power settings I noted in the post above, and I don't increase the MP. 30/2200, 13.2 GPH yields TIT 40d LOP at 1615d.

Cheers,
Rick

I discussion was around @donkaye’s comment that he does not run LOP because he does not like the speed/power loss. There should not really be a speed/power loss. One just needs more manifold pressure to run a higher ff while lop to get back the extra speed.

[kortopates]

I discussion was around [mention=7354]donkaye[/mention]’s comment that he does not run LOP because he does not like the speed/power loss. There should not really be a speed/power loss. One just needs more manifold pressure to run a higher ff while lop to get back the extra speed.

Although entirely true statement, reality is because they’re flying ROP at pretty high power, they won’t be able to run LOP that high and keep TIT from exceeding 1600. Many are already running above 1600, such as 1630F, with a power reduction as it but with still too high TIT IMO. But every pilot makes the tradeoff between speed and longevity on their own terms.


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[donkaye]

On 12/7/2023 at 6:35 PM, Jetpilot86 said:

Here is an old quote of yours from 2012 that caught my eye and spawned my question quoting your post, above:

It's not easy, especially since it's been a few decades since I few GA, despite 12k hours since I last few GA.  At least now I know questions to ask vs my younger and dumber days.

By no means am I disputing your experience, which in the Bravo is orders of magnitude more than mine, but trying to understand where those numbers came from as a rookie with a freshly overhauled engine.  I picked it up with 10 SFOH.  It appears you've become even more conservative since your 2012 post, based on your reply here.  My question about the 2012 post is whether you were choosing the 1600-1625 TIT number as richened from a 1750, (100+ ROP), or some other peak value, or is it just a directly derived number from somewhere else?  If so please share the source.

 

Yes, I have gotten more conservative since the 2012 post.  I now don't want to see TIT over 1600.  Although my BS Degree was in Electrical Engineering, I accept the speeds I get, not what the POH says I should get, assuming the configurations are correct.  For the Bravo, the POH doesn't even give percent power settings.  You've got to figure it out by looking at the Red Lycoming Engine Manual.  Each Mooney is different.  They didn't come off of a mechanical assembly line.  Some are faster than others.  Unless there is a gross speed difference, a 5 knot difference doesn't concern me much.  Now a 20 knot difference invariably is a configuration issue from my teaching and flying experience.  Pitch plus power plus configuration gives performance.  For gross differences it's usually a flap issue or a speed brake issue or cowl flap issue.  In the first case the flaps not being fully retracted after climb.  In the second case I've had people not realize the speed brakes were extended.  Especially in the second case that seems inconceivable, since there is so much disturbance over the wings.  The same goes for not closing the cowl flaps after level off.  That will account for at least a 3 knot speed difference.

I took both the in person APS Course and their online course.  I have nothing against LOP.  I just haven't been successful with my engines in getting them to run smoothly enough for me to feel comfortable with it.  I have one Bravo student who insists on running his LOP, and it always seems rough to me.  He has also spent lots of shop time with problems with his engine.  I do have GAMIs on my engine, though.

Based on the Lycoming charts for the TIO540AF1B engine I'm comfortable flying cross country at 29"/2400 rpm (75% Power).  I lean to just under 1600 TIT then confirm the FF at between 17.5 and 18.5 gal/hr.  Like Mike Busch I just go there immediately without leaning to peak and then richening.  I never get in the Red Box that way.  Next time I fly I'll do a quick check on how much ROP it is.  I got the original setting from doing that many years ago, so I expect it to be about 100°.