Does octane matter that much?

[sb47]

Octane is a measure of resistance to detonation. Which occurs after the spark plug fires. Pre ignition happens because something in the combustion chamber is glowing red hot and acts as a glow plug. High Octane fuel prevents pre ignition to a degree, by not allowing detonation to happen and the resulting high combustion chamber temps that cause pre ignition.

I agree hot embers can pre ignite fuel but gas can ignite from compression alone without a hot ember. Same with diesel can be ignited from compression alone. The hot embers are usually carbon buildup in the chamber but they are not needed to ignite fuel under high compression.

 

[sb47]

That particular fuel is optimized for four cycle engines. Better results can be had with a two cycle specific fuel.
And I am not surprised it felt more powerful as that particular fuel has a decent o2 content.

I agree but thats all I had on hand. I run that in my 4 stroke motorcycles and ATV's. All my scoots have at least 12.5 to 1 with one being 14. to 1.
Anything lower then 105 causes knocks and overheating.

 

[sb47]

Octane rating has zero to with Flashpoint, period...

Ok flash point was the wrong analogy.

 

[Bob Hedgecutter]

It's the "power" of octane, baby.

They cannot resist.....

But what is the flash point of flatulence versus the flash point of hot oral air debating flash point?

 

[OM617YOTA]

Flash point as it pertains to oil and fuel is relevant only for shipping purposes.

Maybe for engine use.

I'm a kerosene lantern collector. Try burning gasoline in a kerosene lantern and you'll learn why flash point matters on a practical level.

 

[drumbum]

Maybe for engine use.

I'm a kerosene lantern collector. Try burning gasoline in a kerosene lantern and you'll learn why flash point matters on a practical level.

Wickies or pressure?

 

[bwalker]

Wickies or pressure?

The only lantern I have burns coleman fuel or gasoline. Lanterns are out of my wheelhouse and really not germain to what's being discussed here.

 

[drumbum]

The only lantern I have burns coleman fuel or gasoline. Lanterns are out of my wheelhouse and really not germain to what's being discussed here.

Thank for letting me know your opinion. I've been wondering all day.

 

[bwalker]

Thank for letting me know your opinion. I've been wondering all day.

I didn't provide an opinion. I made two statements.

 

[Slotracer577]

I'll say it again octane is not as important as the quality of the fuel. Every brand has there own additives and quality control that have much more to do with how a fuel preforms. Octane ratings are posted to give you an idea to what application you need it for, if you take the time to read and understand what octane is. Octane is the flash point, period.

Octane is not the flash point. Have you ever watched or done an octane test? The octane number is the % of pure octane that has equal knock resistance to the fuel In question.
To determine the octane of a fuel, you run your test fuel in a test motor, research or motor style depending on which number you are testing. adjust to find where it knocks, then change the fuel from the test fuel to a mix of octane and another hydrocarbon. When the mix of octane starts to knock, that % of octane is the octane number.

flash point is the temperature that a fuel will support burning. Low flash point hydrocarbons are dangerous because they will burn at room temperatures. High flash points mean it won’t burn unless heated. Flashpoint is useful to compare oils and how well they burn, thus leaving spooge.

 

[GeorgiaVol]

So what effect does the different oil ratios have on octane and what is the ideal octane/fuel/oil mix?

 

[bwalker]

Octane is not the flash point. Have you ever watched or done an octane test? The octane number is the % of pure octane that has equal knock resistance to the fuel In question.
To determine the octane of a fuel, you run your test fuel in a test motor, research or motor style depending on which number you are testing. adjust to find where it knocks, then change the fuel from the test fuel to a mix of octane and another hydrocarbon. When the mix of octane starts to knock, that % of octane is the octane number.

flash point is the temperature that a fuel will support burning. Low flash point hydrocarbons are dangerous because they will burn at room temperatures. High flash points mean it won’t burn unless heated. Flashpoint is useful to compare oils and how well they burn, thus leaving spooge.

Actually flash point is useless when comparing oils. The only thing it will tell you is if the oil has a diluent or not and what temp that diluent will ignite.
Flash point gives zero insite as to the quality of the actual lubricant.

 

[bwalker]

So what effect does the different oil ratios have on octane and what is the ideal octane/fuel/oil mix?

That depends. Same oils my decrease and some may increase octane. Honda HP2 actually has cumene in it which has a R+M/2 octane of 107.

 

[Huskybill]

When I purchased my Husqvarna saws my dealer told me to use nothing but high test( life before corn gas) in all my power equipment.
My saws at 38-1.

 

[bwalker]

When I purchased my Husqvarna saws my dealer told me to use nothing but high test( life before corn gas) in all my power equipment.
My saws at 38-1.

You certainly won't hurt anything following that advice.
Honestly I use only premium in O PE because of it being ethanol free in my area. The actual engines don't build enough compression to need it. Even ported ones.

 

[OM617YOTA]

Wickies or pressure?

Both. Wickies especially, but old school pressure lamps that vent pressure to shut down can be a firebomb if run on gasoline. An old school NRV failure will be spectacular with gasoline as well.

 

[trains]

Both. Wickies especially, but old school pressure lamps that vent pressure to shut down can be a firebomb if run on gasoline. An old school NRV failure will be spectacular with gasoline as well.

ive got a few old petrol soldering irons, the flame causes the heat that makes pressure for them to run.
Few old lanterns, both pet and kero too, nothing like the old alladin no12 to warm and light a room, or the hiss of the tilly or coleman.
Oh, and yeah, a few stoves in pet and kero, some self pressurising, others pump.
Fun to restore those old things too.
Much more civilised conversation that worrying about octane, lets not introduce them to cetane ratings .

 

[Jed1124]

As such, many refineries are moving away from BTEX. Just like Methyl tertiary-butyl ether (MTBE) has been removed from transportation fuels in the USA, BTEX is on its way out.

Great informative post.
My uncle worked in the MTBE plant for Exon. He made 60 and cancer took over his body. From what I heard a lot of guys that worked in that plant suffered the same.
I have a friend who’s father worked in the same plant but doesn’t seem to have been effected. He must be in his late 70’s by now.

 

[ozziechainsaw]

I have runs the same saws on normal and then high octane fuel with little difference. A high octane fuel will burn cleaner and if running higher amounts of oil in fuel it might also help to keep the plug clean as well. If and when you are chasing that last 1-5% extra HP and your chainsaw is under extreme loads and RPM , then it might make a difference.
But in saying all that if you run the wrong or incorect oil to fuel ratio it won't matter what fuel you are runnning the saw will most likely fail.

Cheers

Justin

 

[Canyon Angler]

A high octane fuel will burn cleaner

So...you're an advertising copywriter for one of the oil companies?
Or just gullible?

I want to "gorge myself skinny." Isn't that called "the Oprah diet"?