What octane is best, and why

[huskihl]

That’s what I run now most of the time. It’s not readily available so if I’m doing a bigger project I run local eth and put the non in before I store it.

I’m sure you realize this by now but maybe others don’t. Ethanol contains oxygen. So if you go from being tuned to run non-ethanol and then switch to E10, the added oxygen in the ethanol needs to be compensated for by adding some more fuel.
Basically, you need 14.6 parts of oxygen to burn one part gas. If you add oxygen into your fuel (like running ethanol), now you may have 15 or 16 parts of oxygen to 1 part gas. Need to adjust the H screw to allow more in

 

[pbillyi69]

I’m sure you realize this by now but maybe others don’t. Ethanol contains oxygen. So if you go from being tuned to run non-ethanol and then switch to E10, the added oxygen in the ethanol needs to be compensated for by adding some more fuel.
Basically, you need 14.6 parts of oxygen to burn one part gas. If you add oxygen into your fuel (like running ethanol), now you may have 15 or 16 parts of oxygen to 1 part gas. Need to adjust the H screw to allow more in

kevin you are loaded with lots of good information. i appreciate that you share it freely.

 

[pbillyi69]

thank you

 

[Woodsman]

That’s what I run now most of the time. It’s not readily available so if I’m doing a bigger project I run local eth and put the non in before I store it.

How does your saw run between the higher octane non-ethanol fuel vs the 87 ethanol? Have you noticed any differences in temperature of the saw?

 

[davidwyby]

How does your saw run between the higher octane non-ethanol fuel vs the 87 ethanol? Have you noticed any differences in temperature of the saw?

Haven’t checked temps, only how it runs. The way it runs on 87 eth indicates hotter.

 

[pbillyi69]

im sure it is hotter the saw companies state octane of 89 minimum for heat reasons in all of the owners manuals that i have. for years after they added ethanol to the gas we could only get 92 in efree gas. i ran lots of it and my equipment didnt seem to be lacking any power. i can now get 87, 92, 101 and 110 efree gas at one of the local stations. they wont pump the 87 into your car but they have it.

 

[Powerstroke Cowboy]

I’m sure you realize this by now but maybe others don’t. Ethanol contains oxygen. So if you go from being tuned to run non-ethanol and then switch to E10, the added oxygen in the ethanol needs to be compensated for by adding some more fuel.
Basically, you need 14.6 parts of oxygen to burn one part gas. If you add oxygen into your fuel (like running ethanol), now you may have 15 or 16 parts of oxygen to 1 part gas. Need to adjust the H screw to allow more in

Quick question. Being there's more oxygen in ethanol blends, there should also be more power to be had with ethanol gas. Would that be right? It'll just take more gas to do it, so a tank would not last as long? I wonder if Joe @Red97 has tested different octane ratings and ethanol vs no ethanol gas?

 

[pbillyi69]

if adding oil to the gas lowers the octane by what some say is two points at 50:1 and you start with 87 that means that if you mix it to 32:1 that the end result would be gas with octane of about 80 or 81ish. so start with 95 and add oil at 32:1 to get 87 octane. i didnt math it out exactly but if its true that oil drops the octane of the gas that much there should be more big end failures especially in strato saws, right?

 

[Rich Fife]

I run the "higher grade" pump gas with vp oil 40:1... and I honestly can't tell the difference besides what I pay at the pump for the fuel. And chances are, if someone pumped 87 prior youre still getting the residual 87 in the line... sooooo idk.
My buddies swear by 87 with kinetix full synthetic at 50:1

 

[Rich Fife]

if adding oil to the gas lowers the octane by what some say is two points at 50:1 and you start with 87 that means that if you mix it to 32:1 that the end result would be gas with octane of about 80 or 81ish. so start with 95 and add oil at 32:1 to get 87 octane. i didnt math it out exactly but if its true that oil drops the octane of the gas that much there should be more big end failures especially in strato saws, right?

Does it make it easier to ignite or harder to ignite? It's about the Flash points. I'd assume adding oil raises the flash point. But, idk.

 

[FergusonTO35]

All I can say is that my machines start and run great with name brand corn gas and a healthy dose of Sta-Bil marine fuel treatment. Nearest place I know of that sells straight gas, or at least advertises that they do, is a Sunoco station 40 minutes away. If you are not using stabilizer, then yes e-free is the way to fly. Ethanol gas is nothing new around here, I remember alot of pumps had the contains ethanol signage when I was a kid in the 80's.

 

[pbillyi69]

Does it make it easier to ignite or harder to ignite? It's about the Flash points. I'd assume adding oil raises the flash point. But, idk.

i don't know either. i dont even know if the oil actually does drop the octane level. there isnt that much oil in there even at 32:1. it doesnt seem like 4oz of oil in a gallon would make that much of a change to me.

 

[Powerstroke Cowboy]

if adding oil to the gas lowers the octane by what some say is two points at 50:1 and you start with 87 that means that if you mix it to 32:1 that the end result would be gas with octane of about 80 or 81ish. so start with 95 and add oil at 32:1 to get 87 octane. i didnt math it out exactly but if its true that oil drops the octane of the gas that much there should be more big end failures especially in strato saws, right?

When you say big end, your refering to the big end of the rod, right? How would lower octane due to more oil cause big end failures? I would think the extra oil in the gas would protect the big end even more. Am I missing something?

 

[pbillyi69]

yes i was referring to the rod on a strato saw getting less charge to the bottom but also being hotter from the change in octane. its a question to me. there was discussion on the other oil thread about strato saws having more of the charge directed up or out. making less to the bottom of the case.

 

[jblnut]

Quick question. Being there's more oxygen in ethanol blends, there should also be more power to be had with ethanol gas. Would that be right? It'll just take more gas to do it, so a tank would not last as long? I wonder if Joe @Red97 has tested different octane ratings and ethanol vs no ethanol gas?

I can’t speak to power in chainsaws but I had an ‘01 Grand Prix GTP with a TON of goodies and it made 512whp on E85 and 485whp on Non-oxy 92. Just couldn’t get the power out of “regular” gas until we got well over 100 octane, which makes sense as E85 is in that 105 octane area.

I’ve run 87-92 both ethanol and non in saws and even some E85 in a cheap Holzforma saw once to see what it did. It loved it but took some tuning to make it happy. Doubt the rubber stuff would last long but it ran like a champ.

 

[huskihl]

Quick question. Being there's more oxygen in ethanol blends, there should also be more power to be had with ethanol gas. Would that be right? It'll just take more gas to do it, so a tank would not last as long? I wonder if Joe @Red97 has tested different octane ratings and ethanol vs no ethanol gas?

Sure, it’s a form of alcohol and that’s what they run in race saws

 

[huskihl]

if adding oil to the gas lowers the octane by what some say is two points at 50:1 and you start with 87 that means that if you mix it to 32:1 that the end result would be gas with octane of about 80 or 81ish. so start with 95 and add oil at 32:1 to get 87 octane. i didnt math it out exactly but if its true that oil drops the octane of the gas that much there should be more big end failures especially in strato saws, right?

It can’t drop octane that much or there would be burned up saws everywhere

 

[Khntr85]

an 8 pack of 12oz plastice bottles went from 4.55 to 9.50

Beer healthier than pop…

 

[pbillyi69]

It can’t drop octane that much or there would be burned up saws everywhere

that's what i thought. but i have nothing but common sense to back me up.... lol

 

[pbillyi69]

Beer healthier than pop…

i agree but i dont drink anymore...