Ardent wrote:I’m one of the few it seems who will cheer lead being removed from avgas. Yes, it is bad for us. No, it’s not killing us tomorrow.

We won’t be without alternatives, a 10:1 motor is nothing new in internal combustion. I just installed a new IO520 myself and am not worried about the fuel of the future.

There are already formulations in testing lead free that can match 100LL in octane lean. I suspect 94UL (avgas without lead) STC leaning charts will become available for high compression motors too, and likely approvals at richer fuel settings will follow if we don’t get an immediate higher octane lead free option.

It’s not rocket science, and there is enough demand. Yes we’ll pay more, that’s the nature of everything these days.

The i0-520 is only 8.5-1. There's a few guys out there that have run them on premium mogas.

so, some ethanol blend is what we will have to use. And just how does that ethanol blend do with fuel selector O rings, fuel tank drain O rings, fuel lines, carburetor parts? What happens to your fuel system when the plane is getting a new panel for 8 weeks?
I run 100LL in my chainsaws, and all small engines I have. Sure, I can run lower octane pump gas, but if they sit for a while, like a dirt bike over the winter, they always start and run great if I use 100LL, not so much with pump gas.

Most of us would be just as happy with widely available ethanol free mogas. Our low compression, normally aspirated engines will do just fine if they ban 100LL. The other 10% of the planes that apparently use the majority of the 100LL can bump down the HP at the next overhaul, or bump up to a kerosene smoker. JetA is cheaper anyway.

So put me down in the camp of I hope they ban 100LL. We already have alternatives. 'Course by the time somebody actually does something, I'll prolly be flying an electric motor powered glider. I just won't be hauling the kitchen sink.

Fraser Farmer wrote:

Ardent wrote:I’m one of the few it seems who will cheer lead being removed from avgas. Yes, it is bad for us. No, it’s not killing us tomorrow.

We won’t be without alternatives, a 10:1 motor is nothing new in internal combustion. I just installed a new IO520 myself and am not worried about the fuel of the future.

There are already formulations in testing lead free that can match 100LL in octane lean. I suspect 94UL (avgas without lead) STC leaning charts will become available for high compression motors too, and likely approvals at richer fuel settings will follow if we don’t get an immediate higher octane lead free option.

It’s not rocket science, and there is enough demand. Yes we’ll pay more, that’s the nature of everything these days.

The i0-520 is only 8.5-1. There's a few guys out there that have run them on premium mogas.

Good point and that’s a mild compression ratio in the grand scheme of engines, I think we’ll just have to adapt to higher burn rates. I don’t think the price is going anywhere avgas wouldn’t have anyway.

.

Ardent wrote:

Fraser Farmer wrote:

Ardent wrote:I’m one of the few it seems who will cheer lead being removed from avgas. Yes, it is bad for us. No, it’s not killing us tomorrow.

We won’t be without alternatives, a 10:1 motor is nothing new in internal combustion. I just installed a new IO520 myself and am not worried about the fuel of the future.

There are already formulations in testing lead free that can match 100LL in octane lean. I suspect 94UL (avgas without lead) STC leaning charts will become available for high compression motors too, and likely approvals at richer fuel settings will follow if we don’t get an immediate higher octane lead free option.

It’s not rocket science, and there is enough demand. Yes we’ll pay more, that’s the nature of everything these days.

The i0-520 is only 8.5-1. There's a few guys out there that have run them on premium mogas.

Good point and that’s a mild compression ratio in the grand scheme of engines, I think we’ll just have to adapt to higher burn rates. I don’t think the price is going anywhere avgas wouldn’t have anyway.

.

Why are higher fuel burns needed? Whenever I've ran Mogas I run it at the same settings as when I run AvGas. The trouble is with duel injection you will probably run into vapor lock issues at some point with MoGas. That's something they haven't been able to figure out yet.

A1Skinner wrote:Why are higher fuel burns needed? Whenever I've ran Mogas I run it at the same settings as when I run AvGas. The trouble is with duel injection you will probably run into vapor lock issues at some point with MoGas. That's something they haven't been able to figure out yet.

Vapor lock isn’t an issue with Continental fuel injection but it is with the Bendix fuel injection used on Lycomings. There has been mogas STCs available for fuel injected Continentals for quite a while.

Preaching to those more informed than myself but saying for the discussion 100LL is actually 130 octane, that is 100 octane at lean. With 94UL we’ll be leaning from a much lower starting point octane wise. This isn’t a big problem, and there will be benefits like far less plug fouling and cleaner oil.

We’ll probably just have to accept richer fuel settings if 94UL (avgas without lead) is the next fuel. 8.5:1 on 94 octane is very mild stuff, we’ll still be able to lean. My motorcycles, albeit with more tech, are 11:1 or higher.

There are other lead free fuels in development too, and it’s very likely a higher octane option will come out of it. The last issue is soft valve seats that lead protects, but that can be engineered out of the fleet with hardened seats, or additives that already exist to protect the seats added to the fuel in the interim.

soyAnarchisto wrote: Most of us would be just as happy with widely available ethanol free mogas. Our low compression, normally aspirated engines will do just fine if they ban 100LL......
So put me down in the camp of I hope they ban 100LL. We already have alternatives. .....

I don't agree about hoping they ban 100LL,
but I do agree about making E-zero mogas more widely available.
I think a lot of the GA fleet now burning 100LL could be operated on mogas if it was a practical option.

whee wrote:

A1Skinner wrote:Why are higher fuel burns needed? Whenever I've ran Mogas I run it at the same settings as when I run AvGas. The trouble is with duel injection you will probably run into vapor lock issues at some point with MoGas. That's something they haven't been able to figure out yet.

Vapor lock isn’t an issue with Continental fuel injection but it is with the Bendix fuel injection used on Lycomings. There has been mogas STCs available for fuel injected Continentals for quite a while.

Who had the STC?

Ardent wrote:Preaching to those more informed than myself but saying for the discussion 100LL is actually 130 octane, that is 100 octane at lean. With 94UL we’ll be leaning from a much lower starting point octane wise. This isn’t a big problem, and there will be benefits like far less plug fouling and cleaner oil.

We’ll probably just have to accept richer fuel settings if 94UL (avgas without lead) is the next fuel. 8.5:1 on 94 octane is very mild stuff, we’ll still be able to lean. My motorcycles, albeit with more tech, are 11:1 or higher.

There are other lead free fuels in development too, and it’s very likely a higher octane option will come out of it. The last issue is soft valve seats that lead protects, but that can be engineered out of the fleet with hardened seats, or additives that already exist to protect the seats added to the fuel in the interim.

How big an issue do you think the soft valve seats are? I know my 0-470 digested Mogas just fine, I'd be surprised if they switched to a softer alloy for the i0-520s and i0-550s. Maybe they are softer though.

A1Skinner wrote:

whee wrote:

A1Skinner wrote:Why are higher fuel burns needed? Whenever I've ran Mogas I run it at the same settings as when I run AvGas. The trouble is with duel injection you will probably run into vapor lock issues at some point with MoGas. That's something they haven't been able to figure out yet.

Vapor lock isn’t an issue with Continental fuel injection but it is with the Bendix fuel injection used on Lycomings. There has been mogas STCs available for fuel injected Continentals for quite a while.

Who had the STC?

Peterson - you can get the STC for a Continental IO-470J in a Cessna 180 at least. See their web site.

https://www.autofuelstc.com/order_online.phtml

Higher octane does not change how you lean an engine. It is only a measure of ability to withstand detonation with higher compression. It doesn't make much of a difference in how lean or rich you can run the engine. It doesn't really change your fuel efficiency or burn rates.

Leaded fuel is 4x more lead than the old "leaded" gas available in the 40's and 50's, and caused me stuck valves and a much dirtier running engine. I try to run a 3:1 ratio of mogas to 100LL when I can. Fortunately, we have mogas available at the next field over. There really is no reason why ethanol free mogas could not be more widely distributed - other than the politics of corn.

Running cleaner and cheaper fuel is a good thing for all of us.

Ardent wrote:Preaching to those more informed than myself but saying for the discussion 100LL is actually 130 octane, that is 100 octane at lean. With 94UL we’ll be leaning from a much lower starting point octane wise. This isn’t a big problem, and there will be benefits like far less plug fouling and cleaner oil.

We’ll probably just have to accept richer fuel settings if 94UL (avgas without lead) is the next fuel. 8.5:1 on 94 octane is very mild stuff, we’ll still be able to lean. My motorcycles, albeit with more tech, are 11:1 or higher.

soyAnarchisto wrote:

A1Skinner wrote:

whee wrote:

A1Skinner wrote:Why are higher fuel burns needed? Whenever I've ran Mogas I run it at the same settings as when I run AvGas. The trouble is with duel injection you will probably run into vapor lock issues at some point with MoGas. That's something they haven't been able to figure out yet.

Vapor lock isn’t an issue with Continental fuel injection but it is with the Bendix fuel injection used on Lycomings. There has been mogas STCs available for fuel injected Continentals for quite a while.

Who had the STC?

Peterson - you can get the STC for a Continental IO-470J in a Cessna 180 at least. See their web site.

https://www.autofuelstc.com/order_online.phtml

So it's available for 2 engine models. Impulse has one available for the 210 and Bonanza series with the IO-520 and requires a fairly pricy water injection system install. That's pretty limited...

Fraser Farmer wrote:How big an issue do you think the soft valve seats are? I know my 0-470 digested Mogas just fine, I'd be surprised if they switched to a softer alloy for the i0-520s and i0-550s. Maybe they are softer though.

Yea I’m not sure. That’s a question I’ll have to bring to Pro Aero.

The issue with the soft seats isn’t that they pound out, rather that they stick and tear. The lead prevents the valve tearing little pieces out of the seat progressively. It provides a film barrier that prevents the adhesion and “plucking” of soft material out of the seats by the valve. There are already very good fuel additives on the market that prevent this, and one would presume they’ll be added to future lead free avgas. At least until all the old soft seats are out or circulation.

soyAnarchisto wrote:Higher octane does not change how you lean an engine. It is only a measure of ability to withstand detonation with higher compression. It doesn't make much of a difference in how lean or rich you can run the engine. It doesn't really change your fuel efficiency or burn rates.

Leaded fuel is 4x more lead than the old "leaded" gas available in the 40's and 50's, and caused me stuck valves and a much dirtier running engine. I try to run a 3:1 ratio of mogas to 100LL when I can. Fortunately, we have mogas available at the next field over. There really is no reason why ethanol free mogas could not be more widely distributed - other than the politics of corn.

Running cleaner and cheaper fuel is a good thing for all of us.

Except, and I’m always learning, a leaner mixture of the same fuel has a much lower resistance to detonation than a richer one. At lean burn, 100LL is 100 octane and very resistant to detonation. At rich measurement, it’s 130 octane.

Mogas at lean burn will be much lower octane and more prone to detonation earlier in leaning, as its octane / detonation resistance is measured differently than avgas. Its rating is much closer to the “rich” method of rating avgas at 130 octane.

This is where my richer fuel settings thoughts come from, in that I think it likely we may need to richen the mixture to increase knock resistance. And as always, the major asterisk applies to my thoughts that I’m always learning. If you know more on the subject I’m very much open to it!

I’m like you it sounds like and prefer to see the lead out.

Mogas is fine and dandy, but I can't recall ever being at an airport that had it. Around here non-ethanol gas is only available 2 places within 45 minutes by car, and its 88 octane. It would have to be pretty darn cheap for me to drive 45 minutes to fill up 6 or 8 CLEAN gas cans put them in my car, then drive 45 minutes back, then deal with the hassle of dumping 5 gallon cans into the tank while on a ladder. I'd have more time in fueling and related hassles than I would in flying!
Good luck even finding a gas can that doesn't suck due to government regulations!

If you don't run 100LL, good for you. But why would you hope the government gets more involved with anything we do?

There are a lot of reasons to be happy about lead leaving fuel.

This said, this isn’t a discussion about the 100LL pump running dry and making you drive to the other field with jerries. It’s simply a talk about the inevitable, a different formulation or avgas coming out of the same pump without lead in it.

The cheapest thing we put into our airplanes is gas/fuel

As of 10 seconds ago, Avgas at my airport is $6.30

Not far from $7 already

$4.45 @ kcii