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Are GAMI Useful for M20J IO-360 Engines?


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If your 70% or lower, although I’ve read 75% I accept 70, heck I use 65% to be safe, you can’t hurt the motor doing anything you want to with mixture. I think we accept that.

So set up cruise at 65% power ROP, then using your single probe EGT find peak, then keep leaning until one mark lower than peak, enjoy your day. You will be close enough to best BSFC, a little over lean, but close enough for most.

I don’t have it handy but back in WWII the P-38’s economy cruise was to set up normal long range cruise settings, flip the switch that disabled the prop governor, lean until there was a 50 RPM drop, turn the governor back on, repeat for the other engine. That put them LOP and at about the best BSFC, they didn’t know they were LOP, didn’t care, just knew they were extending their range. There were problems with new pilots forgetting to go back to auto rich when the enemy was spotted.

Now if you choose to do the LOP thing above I’ll accept 70% then you do need at least an engine monitor, preferably one with settable alarms.

Personally I fly LOP to save $$, and I understand that to really save fuel you both slow down AND run LOP, so I use 65% ROP power settings, of course LOP power will be less than best power if MP and RPM are the same.

Is the accepted number of power production per fuel flow 14? Meaning when LOP you get 14 HP per gl of fuel flow per hour?

If so then 65% of 200 is 130, 130 div by 14 = 9.25, so if your LOP and fuel flow is less than 9.25, your below 65% and safe

70% works out to a nice even 10 GPH.

Check my math, I’ve been wrong before, and I may be wrong about the 14 thing too.

Another way to ensure your in the safe zone, personally I’m never close to 9 GPH when LOP, much less 10.

At higher altitudes you’ll experience that even wide open that LOP may not give you enough power, if so start running richer, gradually increasing until your at best power, when you get there at 2700, well that’s all there is :)

Whats the average labor for an engine monitor install?

Then Lycoming has published for max engine longevity, operate the engine at 65% or less power, so there’s another reason to stay below 65% power.

LOP isn’t for those who desire speed above other considerations, but it’s another tool.

 

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I think it’s good to review how GAMIjectors work. An engine gets rough when all cylinders are not making the same horsepower. If the cylinders and ignition meet specs, the power balance will be determined by the uniformity of mixture admitted to the cylinders.

The Lycoming IO-360 has separate intake tubes of equal length going to each cylinder so the airflow is quite even. The intake air passes through the engine sump which heats it. While this reduces volumetric efficiency somewhat, it aids in vaporizing the fuel just before the intake valve opens making the mixture more uniform. The RSA fuel injector nozzles are pretty well matched, so the fuel flow is even. There is not a lot to improve here. In fact, a carbureted O-320 will run LOP - Piper published a procedure for doing so in the PA28-161 POH back in the 1970s.

Many Continentals have a much less efficient intake design. It works well enough ROP, where they were designed to run, because power output is much less sensitive to mixture strength ROP than LOP. Compared to the Lycoming design, the Continental intake does not do as good a job of distributing air equally to the cylinders, it doesn’t warm the air, and turbulence within the plumbing allows mixture intended for some cylinders to backflow through the intake manifold and end up at other cylinders. Improving all this requires tailoring the amount of fuel flow through each injector nozzle to even out the mixture between the cylinders.

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1) The nice thing about adjusting fuel flow in an injector…. Select the next drill size up… drill larger hole.  The noncompressible nature of gasoline keeps the variance to a minimum… liquids have difficulty following rules… this is why we need straight lengths before and after FF sensors…

2) Adjusting airflow… porting, polishing and flow benching until finished…. And this only covers the cylinders, it leaves out balancing the intake tubes… intake tubes and six cylinder engines get more complex… air doesn’t like to follow any rules…

3) four barrel carbs start to sound interesting… :)

4) Single Jet carbs get all kinds of variations spread amongst the four cylinders….  Mostly balanced near WOT only…. (Single point of design)

5) Log style intakes work OK… curvy equi-length tubes are balanced over a wider range of CFMs….


PP thoughts only, not an engine mechanic…

Best regards,

-a-

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11 hours ago, Philip France 13 said:

Good help : I will definitively try LOP at my next cross coutry trip when 80k or above. If i got it right  : full throttle, 2500rpm, and mixture LOP just passing the peak. Philip

You don’t have to be full throttle or higher altitude.  i regularly run LOP at 22 squared at 1000 MSL and 6.5 gls an hour. just stay below say 70% power and any altitude is fine. Altitude below a certain point is irrelevant, I’d say altitude is irrelevant but higher altitudes LOP just may not give you enough power.

That’s excessively lean, but what the heck you can’t hurt it. Lately if memory serves I’ve bumped it up to 24 /23 and about 8 GPH, but I’m not certain of thise numbers. Every Sunday I fly the identical route and both ways which sort of evens out the winds. Been watching total fuel used at different settings just out of curiosity. Something to do I guess. 

I’ll bet lunch she will run LOP just fine, these motors are the poster child for LOP.

At 8,000 MSL 21 MP and 2500 RPM your pretty close to 70% I think, but check

 

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23 hours ago, PT20J said:

I think it’s good to review how GAMIjectors work. An engine gets rough when all cylinders are not making the same horsepower. If the cylinders and ignition meet specs, the power balance will be determined by the uniformity of mixture admitted to the cylinders.

The Lycoming IO-360 has separate intake tubes of equal length going to each cylinder so the airflow is quite even. The intake air passes through the engine sump which heats it. While this reduces volumetric efficiency somewhat, it aids in vaporizing the fuel just before the intake valve opens making the mixture more uniform. The RSA fuel injector nozzles are pretty well matched, so the fuel flow is even. There is not a lot to improve here. In fact, a carbureted O-320 will run LOP - Piper published a procedure for doing so in the PA28-161 POH back in the 1970s.

Many Continentals have a much less efficient intake design. It works well enough ROP, where they were designed to run, because power output is much less sensitive to mixture strength ROP than LOP. Compared to the Lycoming design, the Continental intake does not do as good a job of distributing air equally to the cylinders, it doesn’t warm the air, and turbulence within the plumbing allows mixture intended for some cylinders to backflow through the intake manifold and end up at other cylinders. Improving all this requires tailoring the amount of fuel flow through each injector nozzle to even out the mixture between the cylinders.

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Walt Atkinson told me years ago that they found that Continental “log runner” intakes were actually quite good at delivering equal amounts of air to each cylinder and that the fuel migrating through the intake was the problem real problem

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35 minutes ago, Shadrach said:

Walt Atkinson told me years ago that they found that Continental “log runner” intakes were actually quite good at delivering equal amounts of air to each cylinder and that the fuel migrating through the intake was the problem real problem

I believe that, because there is no way you could fix air distribution with the injectors. The best you could do would be to get the mixture strengths equalized, but unequal mixture quantities between cylinders would still give unequal powers and the engine would still run rough.

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But would you feel it?

1) It would be nice if all cylinders got the same Fuel/air ratio… EGTs would peek at the same FF.

2) It would also be nice if all cylinders received the same amount of air… flow balancing helps…

3) What happens when a cylinder gets ground a few thousandths over?  Not quite the same volume in each cylinder…
 

4) The log style distribution is really good… at one throttle setting… WOT.  And not too bad at other throttle settings… not good enough to run a Bravo LOP and meet everyone’s expectations….

5) The equilength intake tubes are as good as it gets…

6) The O can run deep LOP until the engine gets quiet… no roughness involved…. Sort of weird when it occurs… :)

7) A Gami spread of 0.0 to 0.1 is possible…

8) +1 when your airflow to each cylinder is different…  we match the FF to each cylinder to it, so they all peak as close together….

9) Matching the ratios is most likely beneficial for TIT control… reproducibility to book numbers….

10) Lycoming builds a curvy tube intake for their IO540…  that would make for a great STC project for Bravo owners…

11) Might get a few more HP with an intake system clean-up….  :)

PP surmising and have gone off the track….

Best regards,

-a-

 

PP thoughts only

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To get a smoother running engine your not going to get there with just injectors, you need to “blueprint” the engine. Not saying injectors don’t help, but for example you don’t make an average grocery getter into a track car by just putting on good tires. 

The closest to that that I’m aware of is Carlos Gann’s “performance” engines. He balances all rotating assemblies to less than 1 gram, then the cylinders are ported and polished to match the ports, I’m sure though as a former NASCR engine builder some port shaping to increase flow probably sneaks in. Add in a seven angle valve job and honing valve guides to very exact tolerances and you get an engine that’s perfectly balanced and about as matched as is possible. Be nice if he CC’d the heads to perfectly match compression ratios but I assume CC’ing an aircraft head may not be practicable. It’s easy on removable heads but don’t know about aircraft heads.

Of course Lycoming could do this, heck they could probably tighten up tolerences with modern manufacturing machining and produce identical cylinders, but the old specs are considered good enough and tightening things up would cost money to fix something that’s not really broken.

There has always been an industry in taking factory spec motors and making them “better”

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1 hour ago, Fly Boomer said:

And then you have formula cars.  It’s amazing how much can be done while staying within strict dimensional specifications.

Not to be argumentative, but they are severely constrained now, what’s amazing is what they could do if allowed, years ago they were making turbine power levels with recip engines.

Rather than all the continuing development of changing rules (they have to change, the Engineer's and mechanics find ways to beat them). I’d like them to go to a few rules like min car weight etc. but to give them x liters of x Octane fuel, perhaps pump gas, and let them build any kind of engine they want to, if they start getting too fast, reduce the fuel quantity to slow them down.

I bet if we did that, there would be some significant new technologies on how to squeeze more power out of less fuel, fuel efficiency would become exceedingly important, and that just might trickle down to the cars you and I drive.

But, would people buy the fuel efficient cars? I think not.

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15 hours ago, carusoam said:

But would you feel it?

Yes you do. Last two airplanes were six cylinders with three blade props, a 540 and a 520, the 520 maybe airframe had something to do with it, but it was smoooth.

I wasn’t looking forward to flying a lawnmower again, not to be unkind, but on average a four cyl swinging a two blade prop isn’t known for smoothness and reminds me of a lawnmower. But the efficiency (MPG) was appealing, plus a big motor Mooney was likely out of my budget.

But this Gann performance motor seems honestly about as smooth as those sixes were, the sound isn’t as smooth, it does have a more of a VW sound as opposed to a 911 sound, but laying your hand on the glare shield with your social finger raised its smooth. May sound silly but that’s always been my vibe sensor, one other way is to lay my head on the window.

I know it sounds like BS and yes prop balancing has a tremendous amount to do with it, but this thing is abnormally smooth

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58 minutes ago, A64Pilot said:

Yes you do. Last two airplanes were six cylinders with three blade props, a 540 and a 520, the 520 maybe airframe had something to do with it, but it was smoooth.

I wasn’t looking forward to flying a lawnmower again, not to be unkind, but on average a four cyl swinging a two blade prop isn’t known for smoothness and reminds me of a lawnmower. But the efficiency (MPG) was appealing, plus a big motor Mooney was likely out of my budget.

But this Gann performance motor seems honestly about as smooth as those sixes were, the sound isn’t as smooth, it does have a more of a VW sound as opposed to a 911 sound, but laying your hand on the glare shield with your social finger raised its smooth. May sound silly but that’s always been my vibe sensor, one other way is to lay my head on the window.

I know it sounds like BS and yes prop balancing has a tremendous amount to do with it, but this thing is abnormally smooth

I think motor mount condition is also big factor. Sixes are inherently smoother but fresh mounts help a lot to dampen out 4cyl vibrations. When I rented 172s I was happy to take the only O300 powered bird in the rental fleet because it felt so much nicer even though it had the least amount of power.  However, when we got a fresh lyc O360 180hp conversion, it transmitted very little vibration to the airframe. The IO320 decathlon I fly is also very smooth. My F model is OK but has not been as smooth since the prop was overhauled 4 years ago. I’ve no doubt that replacing the mounts and balancing the prop would make a big difference.

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39 minutes ago, Fly Boomer said:

People mostly prefer the cheapest goods and services.

In 2010 Toyota brought out I think it was the third generation of Prius, the previous Prius got 50 MPG, with the newer tech they could easily have pushed that number beyond 60 MPG, and the newer car could have been cheaper as it was easier to build.

But instead they bumped the motor size from 1.5L to 1.8 and it produced more power and built a bigger heavier car, and maintained the 50 MPG.

Toyota knew what they were doing, people wanted a bigger, heavier car over fuel efficiency, even in the model that existed for fuel efficiency.

Remember not too many years ago everybody had a small truck in their lineup and several small cars? Most were imports, Fords small truck I think was actually a Mazda for example. But small efficient inexpensive cars and trucks were plentiful.

The reason they are gone is / was politics, but most people don’t want small efficient less expensive vehicles, they have been sold into believing that they want the biggest least efficient things they can finance, and of course that’s where the profits are for the automakers, they didn’t make money on the little trucks and cars like they do full size trucks and SUV’s.

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3 minutes ago, A64Pilot said:

In 2010 Toyota brought out I think it was the third generation of Prius, the previous Prius got 50 MPG, with the newer tech they could easily have pushed that number beyond 60 MPG, and the newer car could have been cheaper as it was easier to build.

But instead they bumped the motor size from 1.5L to 1.8 and it produced more power and built a bigger heavier car, and maintained the 50 MPG.

Toyota knew what they were doing, people wanted a bigger, heavier car over fuel efficiency, even in the model that existed for fuel efficiency.

Remember not too many years ago everybody had a small truck in their lineup and several small cars? Most were imports, Fords small truck I think was actually a Mazda for example. But small efficient inexpensive cars and trucks were plentiful.

The reason they are gone is / was politics, but most people don’t want small efficient less expensive vehicles, they have been sold into believing that they want the biggest least efficient things they can finance, and of course that’s where the profits are for the automakers, they didn’t make money on the little trucks and cars like they do full size trucks and SUV’s.

Yeah, I guess my “cheapest” comment isn’t always true.  But In addition to the Ford “Excessive” or whatever their latest behemoth is called, I see tons of Kias on the street, and I’m pretty sure people are buying on price, not frequency of repair and build quality.

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7 hours ago, A64Pilot said:

Not to be argumentative, but they are severely constrained now, what’s amazing is what they could do if allowed, years ago they were making turbine power levels with recip engines.

Rather than all the continuing development of changing rules (they have to change, the Engineer's and mechanics find ways to beat them). I’d like them to go to a few rules like min car weight etc. but to give them x liters of x Octane fuel, perhaps pump gas, and let them build any kind of engine they want to, if they start getting too fast, reduce the fuel quantity to slow them down.

I bet if we did that, there would be some significant new technologies on how to squeeze more power out of less fuel, fuel efficiency would become exceedingly important, and that just might trickle down to the cars you and I drive.

But, would people buy the fuel efficient cars? I think not.

I remember reading that F1 engines were around 85% efficient in converting fuel to usable power.  That is pretty darn good.

EDIT ------------

They are currently over 50% efficiency.

This as of 2021.  In 2014 they were at 44%.

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30 minutes ago, Shadrach said:

If true, that would make them far more efficient than any EV on the market. 

I don’t know about F1, but LI-Ion battery is over 99% efficient, if charged at home, fast charging is much less efficient

https://batteryuniversity.com/article/bu-808c-coulombic-and-energy-efficiency-with-the-battery

The model 3’s motor efficiency is variable of course, pick its most efficient load and RPM and its 96%, but it operates usually in the low to mid 90’s %

https://insideevs.com/news/348504/tesla-improves-motor-efficiency-increase-range/

So with an over 99% efficient battery and a motor in the mid 90’s, you have a power train that’s at least low 90’s% efficient

Thats the “trick” of an EV, at least an efficient one, it’s not the fact that it’s electric, it’s that it can be over 90% efficient.

I suspect however that some of the newer EV’s aren’t nearly as efficient.

I have a 50KWH battery and a range of 270 miles. There are 33 KWH of energy in a gallon of gas, so my battery has the same energy as 1.5 gl of gasoline.

https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent

To equal the model 3’s efficiency with ICE you would have to get 180 MPG.

 

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5 minutes ago, A64Pilot said:

I don’t know about F1, but LI-Ion battery is over 99% efficient, if charged at home, fast charging is much less efficient

https://batteryuniversity.com/article/bu-808c-coulombic-and-energy-efficiency-with-the-battery

The model 3’s motor efficiency is variable of course, pick its most efficient load and RPM and its 96%, but it operates usually in the low to mid 90’s %

https://insideevs.com/news/348504/tesla-improves-motor-efficiency-increase-range/

So with an over 99% efficient battery and a motor in the mid 90’s, you have a power train that’s at least low 90’s% efficient

Thats the “trick” of an EV, at least an efficient one, it’s not the fact that it’s electric, it’s that it can be over 90% efficient.

I suspect however that some of the newer EV’s aren’t nearly as efficient.

I have a 50KWH battery and a range of 270 miles. There are 33 KWH of energy in a gallon of gas, so my battery has the same energy as 1.5 gl of gasoline.

To equal the model 3’s efficiency with ICE you would have to get 180 MPG.

 

But what is the efficiency in making that electricity?

You need to look at fuel to useable power.

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1 minute ago, A64Pilot said:

I don’t know about F1, but LI-Ion battery is over 99% efficient, if charged at home, fast charging is much less efficient

https://batteryuniversity.com/article/bu-808c-coulombic-and-energy-efficiency-with-the-battery

The model 3’s motor efficiency is variable of course, pick its most efficient load and RPM and its 96%, but it operates usually in the low to mid 90’s %

https://insideevs.com/news/348504/tesla-improves-motor-efficiency-increase-range/

So with an over 99% efficient battery and a motor in the mid 90’s, you have a power train that’s at least low 90’s% efficient

Thats the “trick” of an EV, at least an efficient one, it’s not the fact that it’s electric, it’s that it can be over 90% efficient.

I suspect however that some of the newer EV’s aren’t nearly as efficient.

I have a 50KWH battery and a range of 270 miles. There are 33 KWH of energy in a gallon of gas, so my battery has the same energy as 1.5 gl of gasoline.

To equal the model 3’s efficiency with ICE you would have to get 180 MPG.

 

A lithium ion battery is merely a storage device. We’re talking about power generation. Coal fired power plants are far more efficient than most road vehicles at extracting energy from hydrocarbons. It’s why I cringe when people think they’ve made a stinging rebuke of EVs for being powered by coal. However, 85% efficiency is far beyond what we’re getting out of coal fired power plants.

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16 minutes ago, Shadrach said:

A lithium ion battery is merely a storage device. We’re talking about power generation. Coal fired power plants are far more efficient than most road vehicles at extracting energy from hydrocarbons. It’s why I cringe when people think they’ve made a stinging rebuke of EVs for being powered by coal. However, 85% efficiency is far beyond what we’re getting out of coal fired power plants.

Understood, but if your determining the operating efficiency of an EV, you have to add in any inefficiency of the battery too. it’s not correct to just state motor efficiency.

Generating plant wise I believe the GE natural gas turbine with co-generation is the efficiency leader at 60% 62% apparently

https://www.ge.com/gas-power/resources/articles/2016/power-plant-efficiency-record

Coal plants are way down there about 33%, I think some ship Diesels are there. seems ships are as much as 50% efficient https://gcaptain.com/wartsila-introduces-gas-fueled-version-of-worlds-most-efficient-4-stroke-diesel-engine/

https://www.energy.gov/fecm/science-innovation/office-clean-coal-and-carbon-management/advanced-energy-systems/transformative

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You know when I think about a coal plant being 33% efficient, maybe by the time you subtract transmission and distribution losses and charger losses and your charging what I strongly suspect are relatively inefficient EV’s, it’s not a big stretch that you could get just as good an efficiency from an efficient Hybrid.

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