O vs IO

FORANE

FORANE

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FORANE
I have never flown an IO. I am somewhat familiar with injectors in cars having changed them before in a cummins. I have read a little and know the obvious difference regarding one being subject to potential carb ice. I have read of potential for easier flooding an IO, possibly better efficiency with an IO.

So which is better and why? What do you prefer to fly behind?
 
IO, the reasons you stated, more uniform fuel burn, power, economy, carb ice, etc.

Just learn how to do a quick shutdown and restart, priming, etc, if you can operate a carbed engine you'll be more than find in a injected one.
 
IO - it's better plus you can tune your injectors for improved LOP operations. The option to run LOP is a great to have.

Injector tuning can be cheaper and easier in the experimental space.
 
The only negative, and it's a pretty minor one, is that some IO's (Lycoming) have a funky start sequence, and can be finicky on hot starts.
 
IO without a doubt, performance, efficiency, the ability to get smoothly well lean of peak. The negative is the parts are more expensive, but once it's set up it's not a big ongoing expense, it's something you can project onto TBO allowances at a couple dollars an hour which I can easily overcome in fuel savings from having it.
 
IO in an aircraft engine is not true fuel injection. Gas is not injected into the cylinder, like a diesel or newer auto FI.
 
kgruber said:
IO in an aircraft engine is not true fuel injection. Gas is not injected into the cylinder, like a diesel or newer auto FI.
Click to expand...

It is true FI, it sprays fuel into the intake stream at the intake valve. It is a continuous flow system in that the fuel flow is not interrupted when the valve is closed like electronic systems, and it does not spray into the combustion chamber under a timed pulse like direct injection, but it is true mechanical fuel injection as it as been known since the beginning. This is still the same type fuel injection found on a Top Fuel dragster.
 
My primary motivation behind choosing IO is mitigating the carb icing issue. I have no patience for that foolishness anymore.
 
IO is ever so much better for super-charging...
 
I think it depends on what you're doing. Carbs are fine if you're just going for bone simple and a leisure aircraft. Carb icing is a concern, but they're easy to start and operate, plus easier setup and less expensive to repair. Fuel injection is very reliable, but when it has a problem, the servos are expensive.

That said, I would put injection on anything, primarily because of the ability to run LOP which is a big deal for me. The starting on injected engines is really not difficult, you just have to learn whatever the "trick" is for your particular engine. Injected Lycomings are not hard, it's just a matter of getting the routine down. Once you do, no problem.

If you have a plane that already has a carb and it's working fine, I would be less likely to mess around with putting injection on unless it's something you really want.
 
Bill Watson said:
The option to run LOP is a great to have.
Click to expand...

It's better than great. It's a game changer for the cost of ownership. Compare 18 GPH rich of peak vs 13 GPH lean of peak for an IO550. Over the course of 2000 hours, that's 10,000 gallons saved, or about $60k.

$60k! You can actually pay for an engine with the fuel savings if you have fuel injectors that are balanced well enough for smooth LOP operations.
 
on a 4-banger i prefer a carb. Something i can work on myself. there's not much payback on an expensive fuel servo on an engine that only burns 9gph to start with, like mine
 
NoHeat said:
It's better than great. It's a game changer for the cost of ownership. Compare 18 GPH rich of peak vs 13 GPH lean of peak for an IO550. Over the course of 2000 hours, that's 10,000 gallons saved, or about $60k.

$60k! You can actually pay for an engine with the fuel savings if you have fuel injectors that are balanced well enough for smooth LOP operations.
Click to expand...

Plus your engine runs longer to boot. Less carbon deposition, less lead buildup, less fuel dilution of the oil on the cylinder wall....
 
NoHeat said:
It's better than great. It's a game changer for the cost of ownership. Compare 18 GPH rich of peak vs 13 GPH lean of peak for an IO550. Over the course of 2000 hours, that's 10,000 gallons saved, or about $60k.

$60k! You can actually pay for an engine with the fuel savings if you have fuel injectors that are balanced well enough for smooth LOP operations.
Click to expand...

That's some fun math..

Also not everyone with a IO runs LOP, most working planes don't, most seaplanes don't, etc.
 
JHW said:
on a 4-banger i prefer a carb. Something i can work on myself. there's not much payback on an expensive fuel servo on an engine that only burns 9gph to start with, like mine
Click to expand...


Now JW makes an interesting point, that I want more about. So based on what he said, where does the diminishing returns become valid? I mean, is it just as beneficial on a 4 cylinder with a low fuel burn?


Shane
The Squawk Shoppe
Sent from my iPad using Tapatalk
 
Archammer said:
Now JW makes an interesting point, that I want more about. So based on what he said, where does the diminishing returns become valid? I mean, is it just as beneficial on a 4 cylinder with a low fuel burn?


Shane
The Squawk Shoppe
Sent from my iPad using Tapatalk
Click to expand...

It would depend on how much you fly and what breaks over your ownership cycle. The difference in operating cost will be about 1.2 gallons of gas per hour, so figure $6 an hour. The average difference in cost of a major FI repair vs a carb is $1000. You may or may not have to deal with one of these repairs in your ownership cycle.
 
Henning said:
It would depend on how much you fly and what breaks over your ownership cycle. The difference in operating cost will be about 1.2 gallons of gas per hour, so figure $6 an hour. The average difference in cost of a major FI repair vs a carb is $1000. You may or may not have to deal with one of these repairs in your ownership cycle.
Click to expand...
...and of course there is the range thing if traveling is an issue.

When I had my MX180a Maule, I was always wishing for a constant speed prop but never really thought about fuel injection instead of the carb. Wonder how they compare in terms of value and payback.

- Only identified carb icing 2 or 3 times over 1500 hours - all seasons up and down east coast.

- Was anxious about hot starts with my first Lyc IO-540. I followed some direction from someone online who said, "just don't use the boost pump". That has worked every time unless it doesn't, in which case I do the cold start routine.
 
Regarding diminishing returns, it depends on how long you're going to keep the plane. Saving $6/hr over 2,000 hours is $12k. That's not diminishing in my opinion, even if you have to knock off some extra for purchase and repair (in 4,000 hours of injected operations I've had 0 repairs on that hardware). But if you're going to sell the plane in a year or two, then it's not worth it anyway.

I would do electronic ignition before I did fuel injection. Similar benefits on fuel consumption, but also might help a bit at altitude. Actually I want to put it on the 310 once it becomes available - I figured the payoff in about 400 hours.
 
Ted DuPuis said:
I would do electronic ignition before I did fuel injection. Similar benefits on fuel consumption, but also might help a bit at altitude. Actually I want to put it on the 310 once it becomes available - I figured the payoff in about 400 hours.
Click to expand...
Curious as to what 6 cyl ignition you are looking at or hoping to become available. I haven't really been tuned in since making the 2 mag decision on my experimental.
 
FORANE said:
I have never flown an IO. I am somewhat familiar with injectors in cars having changed them before in a cummins. I have read a little and know the obvious difference regarding one being subject to potential carb ice. I have read of potential for easier flooding an IO, possibly better efficiency with an IO.

So which is better and why? What do you prefer to fly behind?
Click to expand...

Don't care. Push handle forward, airplane go faster.
 
Bill Watson said:
Curious as to what 6 cyl ignition you are looking at or hoping to become available. I haven't really been tuned in since making the 2 mag decision on my experimental.
Click to expand...

I've been watching this one:

www.americanpropeller.com/ignition.htm

Since I have prop de-ice I need ones with the mag timing housing, but if you can put a slip ring on you can have a 6-cylinder unit today. When I talked to them about 6 months ago they said they were working through some cert hurdles and it should be a few more months. It's been more than a few now, but we all know how certification goes...
 
Definitely IO for me... even with a 200 hp 4-cyl. The fuel savings are substantial, but more important is the ability to manage CHT's and keep the engine clean internally by not dumping extra fuel through it.
 
KSMooniac said:
Definitely IO for me... even with a 200 hp 4-cyl. The fuel savings are substantial, but more important is the ability to manage CHT's and keep the engine clean internally by not dumping extra fuel through it.
Click to expand...

That's where the real savings are with running LOP, valve and cylinder costs.
 
I sometimes fly a gyroplane powered by an IO-320.
She used to be powered by an O-290 G.
I am based very near the ocean and frequently encountered carb ice during cruise with the O-290.
Because I often fly low and slow (500 AGL 60kts); encountering carburetor ice was disquieting and often cost 200 feet of altitude before it was recognized and rectified.
If I did not pull carburetor heat on approach to land carburetor ice could be a challenge.
Despite pulling carburetor heat being on my pre-landing check list I once turned a simulated engine out landing into an actual engine out landing.
The O-290 burned seven to eight gallons per hour and was older than I am.
The IO-320 burns six to seven gallons and is older than my wife.
In my opinion there can be specific challenges with particular engines that have nothing to do with O or IO so I feel it is useful to go beyond that simple question when contemplating an engine selection.
I also fly a gyroplane with a Rotax 914 with carburetors and a turbocharger and I have yet to experience carburetor ice and she often burns less than five gallons per hour.
I have flown her to a density of 11,800 feet during flight testing (she is an experimental) with no provisions for leaning.
I suspect she could fly higher without leaning but I have not had a reason.
 

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Henning said:
It would depend on how much you fly and what breaks over your ownership cycle. The difference in operating cost will be about 1.2 gallons of gas per hour, so figure $6 an hour. The average difference in cost of a major FI repair vs a carb is $1000. You may or may not have to deal with one of these repairs in your ownership cycle.
Click to expand...
It's not that big a difference in fuel rate. I used to take a lot of trips with another travel air, fuel injected. He would lean using his high end engine monitors and try to squeeze every last bit out of it. I'd lean to rough (listening to loss of prop synch) and then give the throttle a little tap toward rick. The difference was less than a gallon an hour total for both engines. Of course with both of us leaned so far we were only doing ~155kts true but were both doing that same speed.
 
JHW said:
It's not that big a difference in fuel rate. I used to take a lot of trips with another travel air, fuel injected. He would lean using his high end engine monitors and try to squeeze every last bit out of it. I'd lean to rough (listening to loss of prop synch) and then give the throttle a little tap toward rick. The difference was less than a gallon an hour total for both engines. Of course with both of us leaned so far we were only doing ~155kts true but were both doing that same speed.
Click to expand...

I flew my 58 turbo Travelair LOP at 7.7 GPH for 147kts, you were operating LOP as well doing what you did.
 
Henning said:
I flew my 58 turbo Travelair LOP at 7.7 GPH for 147kts, you were operating LOP as well doing what you did.
Click to expand...


Ya..,.sure with 60kts on the tail! That's 3.8gph per engine. Impossible....a mooney J model which is the peak of efficiency will do that speed and fuel burn but that's at 12,000ft.

Ya know it takes almost 2gph to idle a io360....
 
Aaronk25 said:
Ya..,.sure with 60kts on the tail! That's 3.8gph per engine. Impossible....a mooney J model which is the peak of efficiency will do that speed and fuel burn but that's at 12,000ft.

Ya know it takes almost 2gph to idle a io360....
Click to expand...

pretty sure captain henning meant per side
 
Aaronk25 said:
Ya..,.sure with 60kts on the tail! That's 3.8gph per engine. Impossible....a mooney J model which is the peak of efficiency will do that speed and fuel burn but that's at 12,000ft.

Ya know it takes almost 2gph to idle a io360....
Click to expand...

Sigh, 7.7 a side.:rolleyes2:
 
Sac Arrow said:
The only negative, and it's a pretty minor one, is that some IO's (Lycoming) have a funky start sequence, and can be finicky on hot starts.
Click to expand...

Don't know about the funky start sequence, but it's true that it's a pain to start hot. It loves to vapor lock if you don't shut it down with the throttle a bit open. If you don't get it fired off before the whining starts then it's no use.

Our normal start sequence is prime to 3GPH, throttle cracked and mixture off. One of our IOs almost has to be flooded to start, which is a freaking pain.
 
kgruber said:
IO in an aircraft engine is not true fuel injection. Gas is not injected into the cylinder, like a diesel or newer auto FI.
Click to expand...

Direct injection is a pretty new thing even in the car world. What really gets me about aircraft fuel injection is that the mixture is still controlled manually. That's one of the biggest benefits of having fuel injection in the first place, it's supposed to do all that automatically. Just about every car built in the last 30 years has fuel injection that compensates for altitude, yet most aircraft dont. Yeah that makes sense.
 
OK, a Lyco question.

Are there any internal build differences between say an O-360 180hp Lyco and an IO-360 200hp Lyco? Is the extra 20hp solely from the injection?
 
Bill Jennings said:
OK, a Lyco question.

Are there any internal build differences between say an O-360 180hp Lyco and an IO-360 200hp Lyco? Is the extra 20hp solely from the injection?
Click to expand...


Compression.....the 200hp has 8.7 compared to 8.5. It also angular valve design vs parallel, so the cylinder replacement cost is $2,350 vs $1,200!
 
Aaronk25 said:
Compression.....the 200hp has 8.7 compared to 8.5. It also angular valve design vs parallel, so the cylinder replacement cost is $2,350 vs $1,200!
Click to expand...


same old addage in racing....

Speed costs money...... How fast do you want to go ????:rolleyes:
 
Yep that's about it.....the unfortunate part is there is on the certified side there is no competition for Lycoming as they are the sole mfg.

Superior makes a experimental cylinder. The parallel valve has several competitors driving the price down.

I will say the io-360 200hp, with power flow exhaust does move out pretty good on my mooney J model. At 8000ft, I can file 165kts on 11gph or 155kts on 9.2gph
 
Bill Jennings said:
OK, a Lyco question.

Are there any internal build differences between say an O-360 180hp Lyco and an IO-360 200hp Lyco? Is the extra 20hp solely from the injection?
Click to expand...

Bill, all the extra power is from the angle valve heads and the slight bump in compression (the angle valve heads are 90+% of it - they flow that much better). Fuel injection does nothing for rated power.

Example: the O-540 in Ed's Comanche is 250 HP @ 2575 RPM. The IO-540s in the Aztec were... 250 HP @ 2575 RPM.
 
Ted DuPuis said:
Bill, all the extra power is from the angle valve heads and the slight bump in compression (the angle valve heads are 90+% of it - they flow that much better). Fuel injection does nothing for rated power.

Example: the O-540 in Ed's Comanche is 250 HP @ 2575 RPM. The IO-540s in the Aztec were... 250 HP @ 2575 RPM.
Click to expand...

Thanks Ted and others, ok, the heads flow better. That said, I've never heard of a 200hp O-360 Lyco, does one exist or are they all injected?
 
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