252 High power Lop

[Mikosch]

Hi there, 

I am a new owner of a beautiful 252 and am currently experimenting with all kinds of power settings. The engine is remarkably smooth at high power settings LOP. I can lean here to about 80 degrees LOP at WOT,  36 inches, and 2500rpm using about 13 Gal/h doing about 155kt IAS at 8000 feet and the hottest CHT 383 with closed cowl flaps.  At that power setting I am outside of the “red box”. Is there a reason why I should not use this power settings for cruise climb oder cruise as long as the CHT don’t go above 390? 

Best regards form Germany 

Mikosch 

[jlunseth]

Hi Mikosch. Welcome to the forum.  I have a 231 and did the same kind of experimenting you are doing a number of years ago. My engine is not quite the same as yours, TSIO360LB, so same displacement and probably horsepower (there are some 252’s with a 220 horsepower engine, my is 210). Let me start by saying that if you are seeking some kind of “official” blessing on your power settings, say from GAMI/APS or Mike Busch, someone who has run the TSIO360 on a test stand extensively, you aren’t going to find it.  I took the APS seminar several years ago and corresponded with the guys there about my engine. Their experience has been with “big bore” engines of the kind used in the Bonanza, and more normally aspirated than turbocharged. Their WOTLOPSOP mantra was developed for normally aspirated engines.  My point is that whatever power setting you wind up using, you are going to have to be the judge of it. Those of us with some experience can tell you what we have seen, but none of us that I know of has done the work on a test stand and come up with definitive answers.

That said, I like your approach of using high MP to make the mixture leaner, but the numbers have me scratching my head a little.  First, in my TSIO360, a fuel flow setting of 13 gal. per hour is not a lean of peak setting.  It would be pretty much at peak or a little rich of peak.  But I am not the pilot and yours is not my aircraft so it may be you are actually getting lean of peak, I just question whether that is the case.

Lean of peak is a fuel/air ratio. To get there you would make your MP and RPM setting and then pull the mixture back.  You should feel a distinct drop in power or slow down as you go into lean of peak territory.  You should see the EGT’s reach peak and determine which one is the last to peak.  You would then use that cylinder’s EGT to make your power setting.  The reason you want to do that is that if you use the first cylinder to peak, or if you use TIT, there can be a significant difference between where the first cylinder to peak and last to peak are operating, and you can have some cylinders LOP and some at peak or ROP.  I use TIT all the time to make my power settings now, but that is because I have experimented extensively using the individual cylinder EGTs and I have a really good idea what a good power setting is for my engine, so my main objective is to keep TIT at or under 1600.

The formula for determining percent power when lean of peak in the TSIO360 is fuel flow x 13.7 divided by total rated horsepower.  In your case I get 13*13.7=178 divided by 210 is 84% HP. That is a high setting for cruise power.  I use relatively high cruise power settings (many people run LOP at about 65% HP) but I always try to keep the power around 70%. There has been quite a bit of experience with flying turbo Mooneys constantly at high power settings and while they seem to work fine for a particular flight, long term durability is not good.  I also turn my MP down to 34”. I just don’t need full throttle to make 70% power, and remember that you are turning the turbo at max to RPMs to make that MP. Over time that may lead to a shorter turbo life.

My lean of peak power setting in my 231 is 11.1 GPH, 2450 RPM’s, 34” of MP.  I have a JPI 930 (good engine analyzer) and pretty much anything in the 12 GPH range is right around peak, anything in the 13’s or higher is rich of peak.

Now, that is my engine not yours, so if you have a good engine analyzer and you really are 80 lean of peak, then I am not going to tell you to do something else.  However, that power setting looks more like an 80 rich of peak power setting to me, than a lean of peak power setting.  80 rich of peak is pretty hard on the engine.

What kind of engine analyzer do you have and what instrument(s) are you using to determine what peak is and how far lean or rich of peak you are?

[aviatoreb]

2 hours ago, Mikosch said:

Hi there, 

I am a new owner of a beautiful 252 and am currently experimenting with all kinds of power settings. The engine is remarkably smooth at high power settings LOP. I can lean here to about 80 degrees LOP at WOT,  36 inches, and 2500rpm using about 13 Gal/h doing about 155kt IAS at 8000 feet and the hottest CHT 383 with closed cowl flaps.  At that power setting I am outside of the “red box”. Is there a reason why I should not use this power settings for cruise climb oder cruise as long as the CHT don’t go above 390? 

Best regards form Germany 

Mikosch 

What is your TIT showing at that setting?

My engine is quite different - its the TSIO520NB, but as for my engine, if I try higher power settings LOP then the TIT starts becoming the limiting factor.

[Mikosch]

29 minutes ago, aviatoreb said:

What is your TIT showing at that setting?

My engine is quite different - its the TSIO520NB, but as for my engine, if I try higher power settings LOP then the TIT starts becoming the limiting factor.

TIT was in the low 1500 area. My max TIT is 1650 

[LANCECASPER]

Just now, Mikosch said:

TIT was in the low 1500 area. My max TIT is 1650 

You are rich of peak

[aviatoreb]

26 minutes ago, Mikosch said:

TIT was in the low 1500 area. My max TIT is 1650 

That's not. bad at all.

I remember reading - but have not found just now - that some bonanza owners like to run LOP at 85% power as standard cruise settings with the idea the ICP's are nonetheless lower than ROP at 75%.  And that some even run at 90%.  I think I read that on pelican's perch, by Deakin, this guy but not this particular article. https://www.avweb.com/features/avweb-classics/pelicans-perch/pelicans-perch-65where-should-i-run-my-enginepart-3-cruise/

I might well run 85% LOP if it weren't that my TIT gets too hot.  

E

 

[Oldguy]

Maybe @gsxrpilot and some other 252 drivers can chime in...

[Parker_Woodruff]

3 hours ago, Mikosch said:

Hi there, 

I am a new owner of a beautiful 252 and am currently experimenting with all kinds of power settings. The engine is remarkably smooth at high power settings LOP. I can lean here to about 80 degrees LOP at WOT,  36 inches, and 2500rpm using about 13 Gal/h doing about 155kt IAS at 8000 feet and the hottest CHT 383 with closed cowl flaps.  At that power setting I am outside of the “red box”. Is there a reason why I should not use this power settings for cruise climb oder cruise as long as the CHT don’t go above 390? 

Best regards form Germany 

Mikosch 

What was the outside air temp at 8000 feet?  My only immediate concern is if this was a VERY cold day, that could mask a high power/high ICP setting which would otherwise result in very high CHTs.

[gsxrpilot]

Hi Mikosh, 

Congratulations on owning and flying the best model Mooney ever made :-).  I might be just a bit biased in that opinion, but not by much. 

As other's have said, I believe you are still ROP at that power setting. And that is actually a more common power setting for a naturally aspirated engine than a turbo.  Running a turbo at WOT and at anything other than full rich, is probably going to eating cylinders. With a NA engine, the MP drops as you climb, and so you'll also reduce the mixture accordingly to match. But with the turbo, as you see, it will maintain the full 36" MP regardless of altitude. So it's appropriate to run full rich if running full MP.

Here is how I run my 252... 

Climb - 36" MP, 2650 RPM, 26 gph. So that's WOT, full prop, full rich.
ROP Cruise - 28" MP, 2500 RPM, 14 to 15 gph - this is about 75% power at 100° ROP
LOP Cruise - 25" MP, 2500 RPM, 9.5 gph - this is about 62% power at 30° LOP

1600 hours on original cylinders and original turbo, still going strong.

I'm also happy to share all my engine data with you. Just send me a PM.

[Parker_Woodruff]

6 minutes ago, gsxrpilot said:

 

As other's have said, I believe you are still ROP at that power setting.

I don't think so at 13GPH.  He'd be getting detonation like crazy if ROP.

I experimented with a LOP climb in my M20K and the FF was about 13-13.5 GPH IIRC.

[Mikosch]

1 hour ago, jlunseth said:

Hi Mikosch. Welcome to the forum.  I have a 231 and did the same kind of experimenting you are doing a number of years ago. My engine is not quite the same as yours, TSIO360LB, so same displacement and probably horsepower (there are some 252’s with a 220 horsepower engine, my is 210). Let me start by saying that if you are seeking some kind of “official” blessing on your power settings, say from GAMI/APS or Mike Busch, someone who has run the TSIO360 on a test stand extensively, you aren’t going to find it.  I took the APS seminar several years ago and corresponded with the guys there about my engine. Their experience has been with “big bore” engines of the kind used in the Bonanza, and more normally aspirated than turbocharged. Their WOTLOPSOP mantra was developed for normally aspirated engines.  My point is that whatever power setting you wind up using, you are going to have to be the judge of it. Those of us with some experience can tell you what we have seen, but none of us that I know of has done the work on a test stand and come up with definitive answers.

That said, I like your approach of using high MP to make the mixture leaner, but the numbers have me scratching my head a little.  First, in my TSIO360, a fuel flow setting of 13 gal. per hour is not a lean of peak setting.  It would be pretty much at peak or a little rich of peak.  But I am not the pilot and yours is not my aircraft so it may be you are actually getting lean of peak, I just question whether that is the case.

Lean of peak is a fuel/air ratio. To get there you would make your MP and RPM setting and then pull the mixture back.  You should feel a distinct drop in power or slow down as you go into lean of peak territory.  You should see the EGT’s reach peak and determine which one is the last to peak.  You would then use that cylinder’s EGT to make your power setting.  The reason you want to do that is that if you use the first cylinder to peak, or if you use TIT, there can be a significant difference between where the first cylinder to peak and last to peak are operating, and you can have some cylinders LOP and some at peak or ROP.  I use TIT all the time to make my power settings now, but that is because I have experimented extensively using the individual cylinder EGTs and I have a really good idea what a good power setting is for my engine, so my main objective is to keep TIT at or under 1600.

The formula for determining percent power when lean of peak in the TSIO360 is fuel flow x 13.7 divided by total rated horsepower.  In your case I get 13*13.7=178 divided by 210 is 84% HP. That is a high setting for cruise power.  I use relatively high cruise power settings (many people run LOP at about 65% HP) but I always try to keep the power around 70%. There has been quite a bit of experience with flying turbo Mooneys constantly at high power settings and while they seem to work fine for a particular flight, long term durability is not good.  I also turn my MP down to 34”. I just don’t need full throttle to make 70% power, and remember that you are turning the turbo at max to RPMs to make that MP. Over time that may lead to a shorter turbo life.

My lean of peak power setting in my 231 is 11.1 GPH, 2450 RPM’s, 34” of MP.  I have a JPI 930 (good engine analyzer) and pretty much anything in the 12 GPH range is right around peak, anything in the 13’s or higher is rich of peak.

Now, that is my engine not yours, so if you have a good engine analyzer and you really are 80 lean of peak, then I am not going to tell you to do something else.  However, that power setting looks more like an 80 rich of peak power setting to me, than a lean of peak power setting.  80 rich of peak is pretty hard on the engine.

What kind of engine analyzer do you have and what instrument(s) are you using to determine what peak is and how far lean or rich of peak you are?

I have the TSIO-360-MB that makes full power (210hp) at 36 inches and 2700 rpm. I have a JPI 930 engine monitor. I am pretty sure that I was LOP with that power setting. At full rich I was burning about 22 Gal and then I did the big mixture pull until I felt a loss of power at about 13 Gal. Then I focused on one the EGT of one cylinder ( Nr. 3) wich stabilised at about 1510 degrees and startet enriching the mixture. All EGT rose and the Nr.3 peaked at about 1590. Also the previous owner sometimes used a 75% ROP setting of about 13 Gal and reported CHT in the 400-410 region. That why I am pretty sure that I was LOP.

Is there any hard evidence that using less MP is better for Turbocharger longevity as long as one operates within Temp. Limitations? 

OAT was 10 degrees Celsius at 8000ft. So not especially could.. 

[Mikosch]

31 minutes ago, gsxrpilot said:

Hi Mikosh, 

Congratulations on owning and flying the best model Mooney ever made :-).  I might be just a bit biased in that opinion, but not by much. 

As other's have said, I believe you are still ROP at that power setting. And that is actually a more common power setting for a naturally aspirated engine than a turbo.  Running a turbo at WOT and at anything other than full rich, is probably going to eating cylinders. With a NA engine, the MP drops as you climb, and so you'll also reduce the mixture accordingly to match. But with the turbo, as you see, it will maintain the full 36" MP regardless of altitude. So it's appropriate to run full rich if running full MP.

Here is how I run my 252... 

Climb - 36" MP, 2650 RPM, 26 gph. So that's WOT, full prop, full rich.
ROP Cruise - 28" MP, 2500 RPM, 14 to 15 gph - this is about 75% power at 100° ROP
LOP Cruise - 25" MP, 2500 RPM, 9.5 gph - this is about 62% power at 30° LOP

1600 hours on original cylinders and original turbo, still going strong.

I'm also happy to share all my engine data with you. Just send me a PM.

Thank you. So far I am very happy with my 252  How hot are your CHT at the ROP setting? I never really considered cruising ROP because as you know fuel is not quite as cheap on the other side of the pond :/ I pay around 11$/ gal at my home airport. 

[gsxrpilot]

Just now, Mikosch said:

Thank you. So far I am very happy with my 252  How hot are your CHT at the ROP setting? I never really considered cruising ROP because as you know fuel is not quite as cheap on the other side of the pond :/ I pay around 11$/ gal at my home airport. 

I can't imagine paying that much for fuel! It's a good thing you fly the most efficient airplane in the sky.

In the climb, my CHT's are all below 360. In ROP cruise, they are typically between 370 and 380. 

It sounds like you are actually LOP at 36" and 13 gph. And I can't see a problem with that as long as you don't spend too much time moving from the rich side over to the lean side. At 36" the "Red Box" is pretty big. It probably runs from 100° ROP to 50° LOP. So just don't spend too much time moving through the box.

[jlunseth]

38 minutes ago, Mikosch said:

I have the TSIO-360-MB that makes full power (210hp) at 36 inches and 2700 rpm. I have a JPI 930 engine monitor. I am pretty sure that I was LOP with that power setting. At full rich I was burning about 22 Gal and then I did the big mixture pull until I felt a loss of power at about 13 Gal. Then I focused on one the EGT of one cylinder ( Nr. 3) wich stabilised at about 1510 degrees and startet enriching the mixture. All EGT rose and the Nr.3 peaked at about 1590. Also the previous owner sometimes used a 75% ROP setting of about 13 Gal and reported CHT in the 400-410 region. That why I am pretty sure that I was LOP.

Is there any hard evidence that using less MP is better for Turbocharger longevity as long as one operates within Temp. Limitations? 

OAT was 10 degrees Celsius at 8000ft. So not especially could.. 

That's the problem right there.  If you lean until you see a peak, and then enrich the mixture, you are doing what everyone calls "leaning," but you are leaning rich of peak.  To go lean of peak, once you reach the point where the EGT of the last cylinder to peak stabilizes, you then continue leaning further.  In other words you continue screwing the vernier control out. You will then be lean of peak.

If you enrich from peak, you are rich of peak, and that is what your power setting looks like to me, it looks like a rich of peak setting with a very high manifold pressure. It looks like it is right dead center in the red box, dead center being around 50 dF rich of peak. But dead center would be somewhat higher at a manifold pressure of 36", I think that is right about where you are.

Your CHT"s are cooler than the prior owner because it is winter, wait until summer comes and you would see the 400-410 that he saw.

As far as your "hard evidence" question is concerned, it is the other way around.  There is no evidence one way or the other on what kind of longevity you will get out of a turbocharger if you operate it continuously at max.  Think of it this way.  The turbocharger spins at about 100,000 rpms.  If you require it to continuously make maximum pressure it is going to spin even faster, maybe 120,000.  If you don't mind overhauling the turbocharger a couple of times before the engine reaches TBO then go ahead, that is your choice to make as the owner.  But the whole idea of cruise speeds down in the 65-75% range is to reduce wear on the engine and to keep your maintenance and overhaul costs down. Unfortunately there have been lots of examples where marketing information caused pilots to think they could continuously run at high power settings. But then the pilot/owner would discover that meant a top overhaul and/or turbo overhaul at 400-800 hours.

The authors of the WOTLOPSOP theory of engine operation (Wide Open Throttle Lean of Peak - Standard Operating Procedure) are the guys at GAMI/APS.  That's John Deakin, Walter Atkinson and George Braley.  They have a test bed on which they have run many engines, but their primary experience is in either normally aspirated engines or turbonormalized engines.  Fully turbocharged engines like yours and mine are a different animal, and I have not ever heard the GAMI/APS guys advocate a WOTLOPSOP operation mode for fully turbocharged engines.  When I was working up the settings for my engine I corresponded with Walter a fair amount and they said they did not have experience with our particular engine (the small bore TSIO360) and could not make a firm recommendation.

Also, they do not recommend leaning in the climb.  That is a normally aspirated engine method of operation. The reason for doing it is that as the aircraft ascends, ambient pressure drops and therefore induction pressure (manifold pressure) drops.  The mixture knob needs to be leaned out to keep the fuel air ratio where it was at takeoff elevation because of the MP drop.  Again, that is the method of operation for a normally aspirated engine. Turbocharged engines make full manifold pressure all the way up to critical altitude, so there is no reason to lean the fuel flow.

The GAMI/APS guys recommend climbing a turbocharged engine at full power, full rich, which should be a fuel flow of 22.5-24 gph.

If you want to use something like your power setting for cruise, then I would say make it 13.3-.5 GPH and drop the MP to 30".  I believe the power charts actually say something like 29". But you will be operating rich of peak, not lean of peak.

If you want to experiment with lean of peak operations, then lean until the last cylinder peaks, then keep screwing the vernier out further.  The power drop will be significant.

[gsxrpilot]

1 minute ago, jlunseth said:

That's the problem right there.  If you lean until you see a peak, and then enrich the mixture, you are doing what everyone calls "leaning," but you are leaning rich of peak.  To go lean of peak, once you reach the point where the EGT of the last cylinder to peak stabilizes, you then continue leaning further.  In other words you continue screwing the vernier control out. You will then be lean of peak.

If you enrich from peak, you are rich of peak, and that is what your power setting looks like to me, it looks like a rich of peak setting with a very high manifold pressure. It looks like it is right dead center in the red box, dead center being around 50 dF rich of peak. But dead center would be somewhat higher at a manifold pressure of 36", I think that is right about where you are.

I don't think that's what @Mikosch is describing.

2 minutes ago, jlunseth said:

At full rich I was burning about 22 Gal and then I did the big mixture pull until I felt a loss of power at about 13 Gal. Then I focused on one the EGT of one cylinder ( Nr. 3) wich stabilised at about 1510 degrees and startet enriching the mixture. All EGT rose and the Nr.3 peaked at about 1590. Also the previous owner sometimes used a 75% ROP setting of about 13 Gal and reported CHT in the 400-410 region. That why I am pretty sure that I was LOP.

Is there any hard evidence that using less MP is better for Turbocharger longevity as long as one operates within Temp. Limitations? 

OAT was 10 degrees Celsius at 8000ft. So not especially could.. 

At full rich I was burning about 22 Gal and then I did the big mixture pull until I felt a loss of power at about 13 Gal. - This loss of power occurs PAST peak on the lean side of peak.

Then I focused on one the EGT of one cylinder ( Nr. 3) wich stabilised at about 1510 degrees. - That is the EGT of #3 at power loss which is definitely LOP.

startet enriching the mixture. All EGT rose and the Nr.3 peaked at about 1590. - Here he is enriching the mixture back to peak where #3 is now 1590.

Assuming #3 was the last cylinder to peak, he would be 80° LOP at 13 gph and 1510° on #3.

OAT was 10 degrees Celsius at 8000ft. So not especially could.. - That's 50° F at 8000 ft which is nearly summertime.

After further review, I'm confident he is LOP.

 

 

[Mikosch]

I think you misunderstood me Jlunseth, 

I wanted to establish how many degrees LOP I was by finding peak form the lean side. I knew I was on the lean side because when I startet to enrich the mixture all EGT rose. 

 

28 minutes ago, jlunseth said:

As far as your "hard evidence" question is concerned, it is the other way around.  There is no evidence one way or the other on what kind of longevity you will get out of a turbocharger if you operate it continuously at max.  Think of it this way.  The turbocharger spins at about 100,000 rpms.  If you require it to continuously make maximum pressure it is going to spin even faster, maybe 120,000.  If you don't mind overhauling the turbocharger a couple of times before the engine reaches TBO then go ahead, that is your choice to make as the owner.  But the whole idea of cruise speeds down in the 65-75% range is to reduce wear on the engine and to keep your maintenance and overhaul costs down. Unfortunately there have been lots of examples where marketing information caused pilots to think they could continuously run at high power settings. But then the pilot/owner would discover that meant a top overhaul and/or turbo overhaul at 400-800 hours.

The authors of the WOTLOPSOP theory of engine operation (Wide Open Throttle Lean of Peak - Standard Operating Procedure) are the guys at GAMI/APS.  That's John Deakin, Walter Atkinson and George Braley.  They have a test bed on which they have run many engines, but their primary experience is in either normally aspirated engines or turbonormalized engines.  Fully turbocharged engines like yours and mine are a different animal, and I have not ever heard the GAMI/APS guys advocate a WOTLOPSOP operation mode for fully turbocharged engines.  When I was working up the settings for my engine I corresponded with Walter a fair amount and they said they did not have experience with our particular engine (the small bore TSIO360) and could not make a firm recommendation.

Also, they do not recommend leaning in the climb.  That is a normally aspirated engine method of operation. The reason for doing it is that as the aircraft ascends, ambient pressure drops and therefore induction pressure (manifold pressure) drops.  The mixture knob needs to be leaned out to keep the fuel air ratio where it was at takeoff elevation because of the MP drop.  Again, that is the method of operation for a normally aspirated engine. Turbocharged engines make full manifold pressure all the way up to critical altitude, so there is no reason to lean the fuel flow.

Regarding the turbo I always thought that temp. is more of an enemy to longevity than boost pressure. Do the GAMI/APS guys have advice about WOT with big bore TC engine? The basic principal would apply to our small bore engine shouldn’t it?

[jlunseth]

Yes, could be Paul.  But what about the 13 GPH? Is that a LOP setting in your engine? It definitely is not in mine.  Given the high MP of 36" I am willing to entertain the idea that the fuel flow would be higher than my normal LOP setting of 11.1, but my setting is at 34", 2 more inches I don't think is enough to keep the fuel air ratio in the LOP range at 13 GPH. That's a 6% increase in MP and a 17% increase in fuel flow.  

[gsxrpilot]

I'm willing to give these power settings next time I'm in the airplane.

I have tried 31" 2450 10gph which were the power settings Brian Lloyd uses in his 231 LB engine, when flying around the world LOP. Those settings gave me nearly 100° LOP. So 13 gph at 36" seems reasonable to me to be LOP as well.

[Mikosch]

4 minutes ago, jlunseth said:

Yes, could be Paul.  But what about the 13 GPH? Is that a LOP setting in your engine? It definitely is not in mine.  Given the high MP of 36" I am willing to entertain the idea that the fuel flow would be higher than my normal LOP setting of 11.1, but my setting is at 34", 2 more inches I don't think is enough to keep the fuel air ratio in the LOP range at 13 GPH. That's a 6% increase in MP and a 17% increase in fuel flow.  

If you fly a 231 or take off power is 40 inches or? My take off power is only 36 inches for the same amount of power. The question is if your engine is lop at 40 inches and  13 gal. I would think so...

[jlunseth]

Just now, Mikosch said:

I think you misunderstood me Jlunseth, 

I wanted to establish how many degrees LOP I was by finding peak form the lean side. I knew I was on the lean side because when I startet to enrich the mixture all EGT rose. 

 

Regarding the turbo I always thought that temp. is more of an enemy to longevity than boost pressure. Do the GAMI/APS guys have advice about WOT with big bore TC engine? The basic principal would apply to our small bore engine shouldn’t it?

OK, but the fuel flow still seems high to me.  Boost pressure is not the enemy, it is the work the turbo has to do to get to that boost pressure.  

The GAMI/APS guys have done some work on big bore engines (i.e. in the range of 550 cu. in.) but when I talked to them they were unwilling to equate that to a small bore fully turbocharged.  Why don't you contact them?  I PM'd you with John Deakin's last email address, they were generally open to talking when I corresponded with them.

[jlunseth]

Just now, Mikosch said:

If you fly a 231 or take off power is 40 inches or? My take off power is only 36 inches for the same amount of power. The question is if your engine is lop at 40 inches and  13 gal. I would think so...

Not my 231.  It has an aftermarket intercooler and with that, we generally operate using the 252 charts.  Actually, I don't use any charts anymore, I use what I learned from APS and, like you, my own experiments. 40 inches would be an overboost in my engine.

[Parker_Woodruff]

54 minutes ago, Mikosch said:

 

I wanted to establish how many degrees LOP I was by finding peak form the lean side. I knew I was on the lean side because when I startet to enrich the mixture all EGT rose. 

 

 

This is the way to do it, especially on the first time you try high power LOP with your plane.

Start well-LOP at a power setting you can't hurt the engine at (60%).  Increase power and lean/enrichen mixture accordingly.

[kortopates]

@Mikosch at 13 GPH LOP you are nearly at 85% power. A couple thoughts, its really hard to believe your TIT is that low, I wonder if your TIT probe is indicating properly. (The TIT and EGT probes do eventually fail from tip erosion.) Secondly the manufacture, Continental, certifies and test their engines to a maximum% cruise power. Max cruise power isn't quite what you think but refers to that maximum power where the engine can be leaned - ROP or LOP. Your engines max cruise power is 78.6%, above this Continental is advising to keep it full rich to ensure sufficient detonation margin. Running it LOP reduces ICP which certainly helps with the detonation margin but your somewhat in untested waters. 

I can tell you that when I operate the engine above 70% power LOP I can no longer keep TIT from exceeding my max TIT limit of 1580-1600F. Therefore i don't operate above that LOP. Consequently I would be curious to see your data to get a better idea of what's going on since your numbers are well out of the ordinary.

Create a free account on SavvyAnalysis.com where we can see your data (I looked and don't see any data there yet). Suggest also flying the SavvyTest profile under help.

[Parker_Woodruff]

3 minutes ago, kortopates said:

I can tell you that when I operate the engine above 70% power LOP I can no longer keep TIT from exceeding my max TIT limit of 1580-1600F. Therefore i don't operate above that LOP. Consequently I would be curious to see your data to get a better idea of what's going on since your numbers are well out of the ordinary.

Tempest fine wire spark plugs cooled off my EGT/TIT by something like 25-40 degrees it seemed.  Do you have those yet?

[kortopates]

46 minutes ago, Parker_Woodruff said:

Tempest fine wire spark plugs cooled off my EGT/TIT by something like 25-40 degrees it seemed.  Do you have those yet?

Yes I do, (third set probably). Although possible, I'd expect the lower EGTs to be more from slightly advanced timing, don't have any actual data though. Or perhaps you had some elevated EGTs from high resistance plugs in need of replacement.