Optimizing 201 engine performance

[Riddle78]

Mooney Gurus,

First time posting and I've really enjoyed reading the wealth of knowledge and experience on this forum. I'm sure this is covered somewhere in the 12,000 plus posts on this website but I haven't been able to uncover a thread that speaks to this (so I apologize in advance if there is one). I've owned a '77 201 for almost two years now and I'm not sure I'm setting my cruise power effectively. For example, my last cross country took place in the following conditions:  altitude 9,500, OAT 11C/53F, hottest CHT 385, hottest EGT 1363, 2500 RPM, throttle firewalled, and consuming just shy of 12 GPH. I consistently stayed between 145 and 150 KTAS...is that what I should expect? I thought I could be squeezing a little more out of it, even at that altitude. 

I'll be honest I don't quite grasp the whole LOP and ROP discussion, and I hesitate to take the CHTs above 400 if I don't have to. At what point does the temp typically fall back off as I approach LOP? I'm a total amateur in this regard and I hope someone can make me smarter (and help my motor last longer) with any perspective or advice. Thanks very much in advance.

Chris

Edited May 29, 2017 by Riddle78

[jetdriven]

12gph sounds like a lot.  I can't make mine go over 9.5ish running LOP at that altitude.  Typically peak CHT is around 50-80 ROP, by peak they are down some and by 15-25 LOP, nice and cool. 

[carusoam]

Great first post Chris.

get ready for some discussion...

lots of questions will come regarding confirming your stated details.  Sometimes there are two ways to understand what you may have typed...  (this just happens)

It seams that you have left the mixture settings out of the discussion.  With 12gph FF, at 9k' you may have not adjusted the mixture very much at all...

four cylinder, normally aspirated (non-Turbo like yours) Mooneys only use 10gph under ordinary conditions.  That leaves you with a target of saving about 2gph while you are flying...

do you want to discuss mixture settings from take-off to landing?  How it's done, when it's done, that kind of thing?

Best regards,

-a–

Edited May 29, 2017 by carusoam

[gsxrpilot]

Hi Chris, 

Welcome aboard. Just a couple of notes. Temps won't go down as you approach LOP. They will go down as you go PAST Peak. That's leaving ROP and transitioning to LOP

A quick point of order here... it's good to be doing this as you're learning, above 8000 or 9000 ft. You really can't make enough HP up there to damage the engine even running it in the worst possible way.

First go out and find Peak. Assuming you start at full rich on the mixture, pull the mixture back (leaning). As you do so you should see EGT's all rising. EGT's are the only numbers used to find Peak. As you keep on leaning, (pulling the mixture back), the EGT's will continue to rise and then will start to fall. The point where the EGT's are at their maximum temperatures is Peak. Note your fuel flow at Peak. Note the EGT's at Peak. Peak is a bad place to run your engine for any length of time, and this is why you learn this procedure at high altitude.

If you continue to pull the mixture back, the EGT's will continue to drop and you are going LOP (Lean of Peak). At some point, the engine will start to run rough. You are now a little TOO LOP. So add a little mixture back just to smooth out the engine. Note the EGT temps now. The difference between this value and the EGT's at Peak will be how many degrees LOP you are. Note fuel flow again. And report back to us.

[carusoam]

You might also want to note...

1) which fuel flow instrument you are using...

2) which engine monitor you are using...

This can help others explain more details for your situation...

Best regards,

-a-

[Danb]

Great explanation Paul 

[Bob_Belville]

The "Peak" in the ROP (rich of peak) LOP (lean of peak) is the peak (maximum value) of the EGT for that cylinder. As you slowly lean the mixture the EGT for each cylinder will climb until it "peaks" and then it will go lower as you continue to lean. That's simply a definition.

Now, not all cylinders will peak at the same fuel flow so we refer to the leanest cylinder (first to peak as we lean) and the richest cylinder (last to peak as we lean). Again, we're only talking EGTs, not CHTs.

But we don't care at all what the absolute value of the EGT is. (Vintage Mooneys originally had a single cylinder ALCOR EGT gauge which was marked in 25 deg F segments but had no temperature numbers at all.)

We care about CHTs. Normally, as noted above, as you lean, the CHT (which reacts much slower to mixture changes) will peak and start back down ahead of the EGT. When you understand this statement you'll have about enough knowledge to be dangerous: 40 ROP (remember that's EGT) will be harder on the engine - hotter CHT - than 40 LOP. Example: say #3 cylinder's EGT peaks at 1500 F, btw, not at unusual temp, so 1460 might be ROP or LOP but the CHT might be 30 F lower when it's LOP.

A comment on Fuel flow in your example. At 9500' full throttle (about 21"?) & 2500 RPM at best power mixture is not much over 65% power. If your fuel injectors are reasonably balanced, as they usually are on our IO360s, you should be able to continue leaning mixture to under 8.5 GPH. (8.7 gph is 65% power LOP for our 200HP engine. %HP=FF*15/200.)

Communications ain't easy, you might want to read this thrice.

[Bartman]

At 9,500ft I don't think I could even force my J get up to 385 degrees even at the worst possible setting.  I know this does not answer your question and as a couple of others have stated it would be nice to have additional information regarding your instrumentation and technique.  However, I replaced the very tired, maybe even original looking baffle seals a few years ago and am very happy with my CHTs.  

Go up to 9,500 and just pull the mixture back at WOT and 2,500.  The rate of pull on the mixture should be done over about 3-5 seconds and your fuel flow should be about 8.4 to 8.7 gph when you feel that slight reduction in power.  Voila you are now running LOP without all the fuss. 

[Riddle78]

Thanks for the great explanations. For some reason I've been a little gun shy about bringing the temps up to find peak. I'll take her back up this weekend to find those values and let you know what I come back with. Regarding the engine monitor, I'm using an EDM 700 so I'll be able to cycle between EGT and FF pretty quickly. Sounds like I've been letting the cylinders bang away much harder than need be...

Chris

[carusoam]

The usual thing that makes people gunshy about leaning is the discussion about the red box and what to avoid while doing this.

The red box does exist, but can be avoided strategically...

The good news is that the redbox can be avoided by deliberately using lower power, or flying at high enough altitudes that the MP gets lowered automatically by atmospheric pressure...

get ready. Make a plan. Share your plan around here. Then take the plan flying... stay out of the red box and run your leaning experiments until your are happy...

There is a company that makes a living out of explaining the leaning techniques called APS.  They have an engine lab that you can visit to get trained on all the details. They have a web based training that is ultra interesting...

MAPA has training as well, where you can fly with a Mooney knowledgeable CFII in your plane and go through all the various leaning techniques that start on the ground, get used for T/O, another adjustment during the climb, adjusting again for cruise, more adjustments during the descent...

There are many times an experienced mooney pilot adjusts the mixture.  Thinking about a typical flight, many of us will adjust the red knob specifically for the following stages of the flight...

1) Mixture set for start-up

2) Mixture reduced for taxi

3) mixture set for run-up

4) Mixture set or adjusted for T/O, target EGT method.

5) Mixture adjustments for climb, blue box method. White box for G1000

6) Mixture adjusted for ROP or LOP cruise, peak, 10°LOP, or 50° LOP...

7) Mixture adjustments for the descent.

8) Mixture adjustment,or set for the traffic pattern/go around ready.

9) Mixture adjustments for taxi again.

10) Automatic leaning device for Mooneys. See @takair/Rob for an interesting piece of hardware...

11) when you know all of these, part of the discussion gets simplified to the Big Pull.  I think JimR described this above...

Transition training usually covers these details.  TT comes pretty hard and fast, taking good notes is going to be helpful for reference...

Have you taken any training since you got the M20J? Trying to help point you in the right direction. The money saved covers a lot of the initial training that is done by MAPA, APS, and TTers...

Going flying, get ready to write...

Best regards,

-a-

 

Edited May 29, 2017 by carusoam

[Alain B]

2 hours ago, gsxrpilot said:

Hi Chris, 

Welcome aboard. Just a couple of notes. Temps won't go down as you approach LOP. They will go down as you go PAST Peak. That's leaving ROP and transitioning to LOP

A quick point of order here... it's good to be doing this as you're learning, above 8000 or 9000 ft. You really can't make enough HP up there to damage the engine even running it in the worst possible way.

First go out and find Peak. Assuming you start at full rich on the mixture, pull the mixture back (leaning). As you do so you should see EGT's all rising. EGT's are the only numbers used to find Peak. As you keep on leaning, (pulling the mixture back), the EGT's will continue to rise and then will start to fall. The point where the EGT's are at their maximum temperatures is Peak. Note your fuel flow at Peak. Note the EGT's at Peak. Peak is a bad place to run your engine for any length of time, and this is why you learn this procedure at high altitude.

If you continue to pull the mixture back, the EGT's will continue to drop and you are going LOP (Lean of Peak). At some point, the engine will start to run rough. You are now a little TOO LOP. So add a little mixture back just to smooth out the engine. Note the EGT temps now. The difference between this value and the EGT's at Peak will be how many degrees LOP you are. Note fuel flow again. And report back to us.

A real champ ! 

[aaronk25]

Adjust your cowl flap linkage so that from the back edge of the cowl flap to the underside of the cowl there is 1/2". I could almost bet your cowl flaps are tightly closed.


Sent from my iPhone using Tapatalk

[Tommy]

There are just too many variables to consider here than just LOP and ROP. Baffles, cowl flaps, OATs, oil, spark plugs, engine hours / condition, etc etc. 

One thing is clear though, you are not flying to the true potential of your J that is equipped with an EDM-700 plus FF. At best, you are just wasting a lot of fuel making heat, at worst, you are stressing your engine with CHT of 385+ at cruise. 

MooneySpace is a great resource but there are too many cooks here that will tell you what to do based on their own experiences (ie what works for them on one or two Mooneys that they have flown), which may or may not fit your plane. 

The best approach is to learn and stick to the safest way of flying from a recognized credible expert who has flown many different planes and analysed many engine monitor data like Mike Busch (google EAA Webinar Mike Busch LOP) until you get the hang of it then modify his approach to suit your plane. Along the way, ask specific questions on MS (Question like "I don't quite grasp the whole LOP and ROP discussion" won't really get you anywhere except to confuse you even further). 

Good luck!

 

[TCC]

@carusoam, great thoughts. Care to explain the 'redbox'? I don't want to assume if you mean EGT, CHT, or something else. Thanks.

[carusoam]

The red box or red fin is an area of operation that is prone to engine ping.  An effect caused by High internal cylinder pressures and temperatures....

Try a search for, red box, using the search box in the upper right corner of your browser.

Since I'm not a mechanic, I'm going to go immediately to a resource...

@gsxrpilot gave a few details and names of people that explane this in great detail...

I hope this helps.  I have seen only one engine that ran into this challenge and it really melted a hole in the top out of the piston. I don't see many engines like some MSers do every day...

Another way to cause this challenge is to have the engine timing set to soon BTDC.

PP thoughts only, not a mechanic...

Best regards,

-a-

Edited May 30, 2017 by carusoam

[PTK]

6 hours ago, Riddle78 said:

 ...I'll be honest I don't quite grasp the whole LOP and ROP discussion, and I hesitate to take the CHTs above 400 if I don't have to...

Chris, a bit of advice as you master leaning. Develop a feel for and a habit of avoiding rich mixtures and high CHT's. (and 400°F is too high imo.) It's a deadly combination and bad for the health of your exhaust valves. Sort of like hypertension and high LDL, aka. "bad" cholesterol! 

[Bob_Belville]

You can learn a lot about the high internal engine pressure red box from John Deakin. His Pelican's Perch columns in AvWeb are very highly respected.  https://www.avweb.com/news/pelican/182583-1.html You can also ask Ms. Google for Mike Busch on mixture and leaning.

[Alain B]

27 minutes ago, TCC said:

@carusoam, great thoughts. Care to explain the 'redbox'? I don't want to assume if you mean EGT, CHT, or something else. Thanks.

http://www.eaavideo.org/video.aspx?v=2274677932001

http://www.eaavideo.org/video.aspx?v=2534345030001

 

If you watch those , you get to know most of it ! 

 

[TCC]

Thanks,[mention=7104]carusoam[/mention],[mention=8913]Bob_belville[/mention], @Alain B It's been a long, long time since I've been around a piston aircraft engine. Some jargon isn't as easy to comprehend as others.

 

 

[gsxrpilot]

Just now, TCC said:

Thanks, carusoam, Bob_belville, Alain B. It's been a long, long time since I've been around a piston aircraft engine. Some jargon isn't as easy to comprehend as others.

Just a small technical point. When referring to specific members on the forum, if you'll use the @ with their name, it will let them know you mentioned them.

@carusoam, @Bob_Belville, @Alain B

[TCC]

Just a small technical point. When referring to specific members on the forum, if you'll use the @ with their name, it will let them know you mentioned them.
[mention=7104]carusoam[/mention], [mention=8913]Bob_Belville[/mention], [mention=15239]Alain B[/mention]

Thanks and fixt, except @Alain B. Can't figure that one out. Sorry for the threes drift, too.

[Browncbr1]

15 hours ago, Riddle78 said:

Thanks for the great explanations. For some reason I've been a little gun shy about bringing the temps up to find peak. I'll take her back up this weekend to find those values and let you know what I come back with. Regarding the engine monitor, I'm using an EDM 700 so I'll be able to cycle between EGT and FF pretty quickly. Sounds like I've been letting the cylinders bang away much harder than need be...

Chris

Are your cht probes spark plug collars?   If yes, then 385 sounds ok because those probes indicate about 50 degrees hotter than actual.  But still, all the previous advice about mixture and LOP is correct.  At 10k, I run at peak, 7.8gph FF, 2500rpm and get 140ktas loaded to gross in my stock 67F.  Your J should go at least 10-20ktas faster on the same settings.  

I think you're losing power from being too rich.  

[Bug Smasher]

What is the consensus on running LOP without GAMI injectors on a fuel injected 360 Lycoming? 

[Oldguy]

1 minute ago, Bug Smasher said:

What is the consensus on running LOP without GAMI injectors on a fuel injected 360 Lycoming? 

If you have a recording engine monitor (JPI 800, 830, 900 or the like) with fuel flow, you can upload your data to www.savvyanalysis.com to a free account and run the GAMI analysis. It should give you the information to make the decision for your engine and plane.

I normally run LOP in my J as the difference in FF between the first and last cylinder peaking is 0.2 gph. From what I read, the IO-360-A3B6/A3B6D engines typically have good, even fuel flow when all is adjusted properly and maintained well. Not saying you cannot have one injector out of line with the others, but everything should line up.

[gsxrpilot]

Even if you ask GAMI, they will point you to their Lean Spread test. If your spread is close enough, they'll even tell you that you don't need GAMI's.