?? About octane for mowers and chain saw

[CincyFlyer]

Octane is the measure of ignition delay. The higher the octane, the more the fuel can be compressed before it ignites. For best performance and reliability, you should use the octane that the engine is designed for. Using too low and you will get pre-ignition (knock), using too high and you will have lost power (higher octane fuel actually has less energy in it). Contrary to what some believe, higher octane is not synonymous with better fuel.

Ethanol blended fuel can damage seals and gaskets on older equipment, and is generally less stable, but is not poorer quality or cheaper fuel. Ethanol also has lower energy content than petroleum-based gas: about 10% less. At 10% blend, there is about 1% less energy overall - hardly noticeable.

Actually, octane numbers indicate resistance to detonation, AKA "knock", which occurs after the ignition event. Deflagration is the normal state of affairs in the combustion chamber. Pre-ignition is an ignition event that was unplanned, usually caused by a "hot spot" in the combustion chamber, such as carbon, or a too-hot spark plug.

 

[marchanna]

Actually, octane numbers indicate resistance to detonation, AKA "knock", which occurs after the ignition event. Deflagration is the normal state of affairs in the combustion chamber. Pre-ignition is an ignition event that was unplanned, usually caused by a "hot spot" in the combustion chamber, such as carbon, or a too-hot spark plug.

Do we really need to get that technical? If that's the case, then I can make further corrections to your statements, which in turn you will make further corrections to mine. At the end we have a doctoral thesis that is so technical, that it is lost on the lay people that are viewing this thread to get practical information. I suspect that is not what we're all here for.

But yes, ignition delay was a rather poor choice of words.

 

[MossRoad]

There's about 0.56 grams of lead per liter 100LL AVGAS.
There's 3.785 liters per gallon.
3.785 X 0.56 = 2.12 grams of lead per gallon of 100LL AVGAS.

The average amount of lead in regular gas in the early 70-'s was between 2-3 grams per gallon.

So, current 100LL AVGAS has just about the same amount of lead in it that regular car gas had in the 70's.

100LL AVGAS is currently the largest source of lead emissions in the United States.

In fact, piston engine aircraft emmited more than twice the amount of lead into the atmosphere as industry in 2008. Kinda shocking.

Also, 100LL is about the equiv of 105 octane car gas. Fellas, you chainsaws don't need 105 octane. If they aren't running correctly on what the manufacturer recommends, 87 or 89, its because its broken, or you've done something to the tuning to cause it.

So give up your AVGAS. You're poisoning the kids.

https://www.scientificamerican.com/article/lead-in-aviation-fuel/

Environmental Health Perspectives – Sunset for Leaded Aviation Gasoline?

 

[Reb954]

:yawn:

 

[fried1765]

Which state is that?

The Democratic People's Republic of Taxachusetts is one.
May be others?

 

[fried1765]

There's about 0.56 grams of lead per liter 100LL AVGAS.
There's 3.785 liters per gallon.
3.785 X 0.56 = 2.12 grams of lead per gallon of 100LL AVGAS.

The average amount of lead in regular gas in the early 70-'s was between 2-3 grams per gallon.

So, current 100LL AVGAS has just about the same amount of lead in it that regular car gas had in the 70's.

100LL AVGAS is currently the largest source of lead emissions in the United States.

In fact, piston engine aircraft emmited more than twice the amount of lead into the atmosphere as industry in 2008. Kinda shocking.

Also, 100LL is about the equiv of 105 octane car gas. Fellas, you chainsaws don't need 105 octane. If they aren't running correctly on what the manufacturer recommends, 87 or 89, its because its broken, or you've done something to the tuning to cause it.

So give up your AVGAS. You're poisoning the kids.

Does the Continued Use of Lead in Aviation Fuel Endanger Public Health and the Environment? - Scientific American

Environmental Health Perspectives – Sunset for Leaded Aviation Gasoline?

I plan to give up using my 30 gal. of 100LL per year, at the exact same time that the 159,000 piston powered aircraft across the USA are permanently grounded, for using their 225 million gallons of 100LL per year.
Tell me where I can buy non ethanol gas in the extreme Eastern part of Taxachusetts though, and I will give up 100LL tomorrow!

 

[Michael Aos]

I generally use so little I've been buying the ethenol-free 92-octane engineered fuel in cans from Home Depot / Lowe's.

Works out to around $19/gal.

 

[buickanddeere]

There's about 0.56 grams of lead per liter 100LL AVGAS.
There's 3.785 liters per gallon.
3.785 X 0.56 = 2.12 grams of lead per gallon of 100LL AVGAS.

The average amount of lead in regular gas in the early 70-'s was between 2-3 grams per gallon.

So, current 100LL AVGAS has just about the same amount of lead in it that regular car gas had in the 70's.

100LL AVGAS is currently the largest source of lead emissions in the United States.

In fact, piston engine aircraft emmited more than twice the amount of lead into the atmosphere as industry in 2008. Kinda shocking.

Also, 100LL is about the equiv of 105 octane car gas. Fellas, you chainsaws don't need 105 octane. If they aren't running correctly on what the manufacturer recommends, 87 or 89, its because its broken, or you've done something to the tuning to cause it.

So give up your AVGAS. You're poisoning the kids.

Does the Continued Use of Lead in Aviation Fuel Endanger Public Health and the Environment? - Scientific American

Environmental Health Perspectives – Sunset for Leaded Aviation Gasoline?

I don't know what liberal greenie site you found your numbers from. Here is the actual accurate facts. Avgas 100LL
This grade is the low lead version of Avgas 100. Low lead is a relative term. There is still up to 0.56 g/litre of lead in Avgas 100LL. This grade is listed in the same specifications as Avgas 100, namely ASTM D 910 and UK DEF STAN 91-90.

Avgas 100LL is dyed blue.

To read more about the fuel, download its MSDS now.

Avgas | Shell Global

 

[fried1765]

I don't know what liberal greenie site you found your numbers from. Here is the actual accurate facts. Avgas 100LL
This grade is the low lead version of Avgas 100. Low lead is a relative term. There is still up to 0.56 g/litre of lead in Avgas 100LL. This grade is listed in the same specifications as Avgas 100, namely ASTM D 910 and UK DEF STAN 91-90.

Avgas 100LL is dyed blue.

To read more about the fuel, download its MSDS now.

Avgas | Shell Global

Interesting... Avgas Shell Global... information.
Back in the day, I burned perhaps 12,000,000 gallons of 115/145 Avgas.
Carried 8750 gals. most flights.

 

[goeduck]

I use 91octane non ethanol for my 5 Stihls mixed with ultra Stihl oil. That fuel source is an hour away where my main farm property is. For my 4stroke small gas engines I use 87 non ethanol which is available where I live. The 87 is much less expensive than the 91, combined with the larger fuel usage of the 4strokes are the only reasons I use it over the 91. So it all works out.

The only exception is when our power went out a few weeks ago and I ran the generator for 30hours. The station that sold 87 non ethanol pumps were down. So my generator has residual ethanol in it that I need to drain and pour into one of the cars.

To the OPs question, 90 non ethanol is fine for all your uses.