Opinion on octane and ethanol

[BiodieselNC]

Hey all, I have been thinking a lot about this lately and thought I would ask for opinions regarding octane of gasoline and ethanol vs. no ethanol.

As a preface, I will put out there that most of my saws are running tighter-than-stock squish and therefore a little higher compression. No pop-ups yet, but that may be on the way soon The reason I bring this up is for the sake of detonation, the damage that can come from that, as well as just simply running hotter. I am seeking to protect my equipment as 100 degree summer days on gonna be here soon!

In my area, I basically have two options for gasoline. At least 2 options that don't cost me an arm and a leg. I can purchase ethanol-free gasoline with an octane of 87 or 89. I get the 89. The other option would simply be the regular E10 stuff you get at the pump which I could get 93 octane. No Sunoco or other stations for at least an hour of where I am.

Am I better off buying the 89 octane ethanol-free stuff and just adding some octane booster? or should i get the 93, tune richer, in hopes that I will run cooler/less detonation?

 

[lambs]

This will be interesting

I know little about the stuff other than what I have read here. And in Raleigh, NC, you can still get ethanol free gas (Kroger of all places!) as far as I know.

My vote would be avoid ethanol at all costs. But my saw is stock, so it will be interesting to hear what others have to say. I don't know what's in octane booster, but hopefully it isn't alcohol!

By the way, Bio, did you get any tornado damage? Hope not for your sake.

 

[Anthony_Va.]

I'm no expert on it either, but I will say that bad Ethanol gas will corrode your carb. It's happened to me. It's not the ethanol, but the mixture of ethanol with water in gas that does it.
If the gas is good gas, I don't think the ethanol is too bad really. Leaving eth fuel in your saws for long periods of time can harm the rubber hoses and other rubber parts.
Theres tons of info on this forum about this. Try the search function.

 

[BiodieselNC]

Thankfully, no damage to our house, we missed the tornado carnage by about 2 miles! But it was crazy while the storm passed over. My dad had some damage to his rental houses in east Raleigh, so I've been doing a lot of cutting trying to clean up all the trees.

So do you know a source that I can get ethanol-free 93 octane? I have not bought fuel from Kroger but I assumed they are getting their fuel from the big guys just like everybody else. I go to a couple of small, privately owned gas stations that get small quantities of ethanol-free gasoline.

Its funny that I am on the biodiesel scene here in NC but I am totally against ethanol. I have been making biodiesel and running it in my truck for 6 years. But if you look at the energy balance, most will agree that ethanol takes more energy to make than you get out of it. Biodiesel from waste oil is also kind of like recycling.

Anyways, any more opinions? How well does octane booster work? I don't buy gasoline other than for my chainsaws. I understand the concept of octane but I'm not so sure its importance in high RPM, air-cooled, 2 stroke engines.

 

[Sagetown]

Don't know about the ethanol. I use 89 octane. Been thinking about going up to 93. Will that actually cause a carb re-adjustment? If it does, I ain't using it.

BiodieselNC ~ Thankfully, no damage to our house, we missed the tornado carnage by about 2 miles! But it was crazy while the storm passed over. My dad had some damage to his rental houses in east Raleigh, so I've been doing a lot of cutting trying to clean up all the trees.

It was a rough night around here too. Stuff going on all this week. Hail yesterday, and today, and who knows what tomorrow?

 

[CJ8Ted]

I'm about ready to fill my mix jug and I think I'm going to get 93 w/ ethanol from a station that sells a lot of gas (fresh) rather than non ethanol gas from the station close by that does not sell as much gas and may not be vary fresh. I use marine grade Sta-ble to fight ethanol, water, and to keep the gas fresh.

Ted

 

[eMGunslinger]

Ethanol problems-decreases shelf life, can possibly have fuel line diaphragm problems long term (person experience is whatever it works no problems here)
Octane-this is a joke. Plain and simple higher octane gas is flame retardant until compressed a certain amount. Hi-OCT less prone to premature detonation. Running Hi-OCT gas in low compression motors can actually degrade power.

 

[northwest coast]

Octane-this is a joke. Plain and simple higher octane gas is flame retardant until compressed a certain amount. Hi-OCT less prone to premature detonation. Running Hi-OCT gas in low compression motors can actually degrade power.

does everybody agree with this ?? the kid at the repair shop told me not to run 93 octane because it can cause premature detonation, i am very curious though.

 

[madhatte]

The whole point of higher-octane gasoline blends is to prevent detonation at higher compression. See, here, is a description of how the myth of "Octane = Power" is misguided. Point: if the manual says 89, run 89. If it says 92, run 92.

There is , of course, a However. If you mod the saw such that compression is increased, run it and experiment. Somewhere, there will be a balance between Big Octane Number and What You Can Afford To Run. Beyond that you will be wasting money on already-too-expensive gasoline.

 

[SkippyKtm]

Hey all, I have been thinking a lot about this lately and thought I would ask for opinions regarding octane of gasoline and ethanol vs. no ethanol.

As a preface, I will put out there that most of my saws are running tighter-than-stock squish and therefore a little higher compression. No pop-ups yet, but that may be on the way soon The reason I bring this up is for the sake of detonation, the damage that can come from that, as well as just simply running hotter. I am seeking to protect my equipment as 100 degree summer days on gonna be here soon!

In my area, I basically have two options for gasoline. At least 2 options that don't cost me an arm and a leg. I can purchase ethanol-free gasoline with an octane of 87 or 89. I get the 89. The other option would simply be the regular E10 stuff you get at the pump which I could get 93 octane. No Sunoco or other stations for at least an hour of where I am.

Am I better off buying the 89 octane ethanol-free stuff and just adding some octane booster? or should i get the 93, tune richer, in hopes that I will run cooler/less detonation?

Mang, I wish I had the same problem as you! I can't get ethanol free gas anywhere except maybe the local airport.

I would go with the 89 octane ethanol free stuff and experiment a little, all you need is enough octane to avoid detonation, you could add some octane boost, but I'd check to see first if you really need it.

This is an detonation damaged piston the yellow deposits are what to look for.
Here a LINK to the site I went to.

 

[CJ8Ted]

I was under the inpression that the higher the Octane numbers the gas has, the lower the Noctane numbers it has, and Noctane is what makes valves ping on my Jeep:msp_ohmy: The other thing is with the higher Octane numbers "as I know it" it runs cooler temp wise and that is what you want with an air cooled engine.

Ted

 

[eMGunslinger]

I was under the inpression that the higher the Octane numbers the gas has, the lower the Noctane numbers it has, and Noctane is what makes valves ping on my Jeep:msp_ohmy: The other thing is with the higher Octane numbers "as I know it" it runs cooler temp wise and that is what you want with an air cooled engine.

Ted

There have been long discussions on this and the folk lore of the amazing 93 oct...people (Bsnelling) has done tests on it and I have witnessed it as well as having no added advantage. Octane is a rating in the US generalized by the AKI (Anti-Knock-Index) which is specific to certain motors for making them knock when you try and use inferior fuel....EX-My 06 GTO can only run 91-93 due to 11:1 compression which is roughly 220psi. I have a saw that compresses at 190psi and runs 93 but that is a little different. Most work saws are in the 150psi range. Honestly you could probably run them on 80 octane if there where such a thing

Octane Rating-basic measurement of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner

 

[sachsmo]

my "opinion" is,

In hot conditions ethonol is prone to boil, it does have some cooling effects on an internal combustion engine though.
Newer saws are running on the ragged edge of lean, more so than the older designs.

If you have a saw manufatured in the last 10 or so years it probably has limiter caps on the H/L needles Some carbs don't even have a "H" needle.

EPA mandates manufacturers sell these saws with limiters to help all of us doofus' (you know, the Gov. "protecting" us from ourselves)

I may be wrong, but I use the best no Ethonol fuel I can get my hands on. With over 20 (running) saws on the shelves, it is sometimes hard to get them all into the rotation.

If I lose a bit of power, don't care, I just remember the old sayings,

"they run best right before they blow"

"lean is mean, but fat is where it's at"



E free gas gives me piece of mind.

 

[eMGunslinger]

E free gas gives me piece of mind.

Gas+E may be bad but Ethanol by itself is amazing higher octane than any other type of fuel besides Methane and Hyrdogen. Ethanol by itself being alky burns amazingly clean.

 

[sachsmo]

Gas+E may be bad but Ethanol by itself is amazing higher octane than any other type of fuel besides Methane and Hyrdogen. Ethanol by itself being alky burns amazingly clean.

Indeed it does,

Problem with e-10, and soon to be e-15 or greater is the average joe doesn't know what a lean engine even sounds like.

Or how to maintain a chain, or even where the mixture screws are.

I have an old Mac with a huge pop-up that I am experimenting with using e-85. It has some nutz. (sure idles weird though)

And if you check with the drag racers, e-85 is a boon (cheaper than swamp gas, and will handle 14:1 compression)

But the E attracts water degrades lines and diaphagms, attacks bare aluminum, and introduces o2. More o2 is a bad thing on an already "limited" engine.

Oh well run 'em til they blow, more projects for me.

 

[eMGunslinger]

But the E attracts water degrades lines and diaphagms, attacks bare aluminum, and introduces o2. More o2 is a bad thing on an already "limited" engine.

Oh well run 'em til they blow, more projects for me.

I didn't realize it had a negative effect on Al, that is interesting.

 

[sachsmo]

Meth is really bad for aluminum, eth not as bad, but still no friend.

 

[Gunther274]

In Minnesota we have access to 91 non oxygenated. Thats what i run

 

[Jim Mesthene]

Read the ingredients. Most octane boosters are alcohol.
E-10 won't cause any problems at all if you use fresh gas, or almost fresh gas that had a stabilizer added when it was fresh. The only problems with E-10 occur with old gas stored in a humid environment. In a worst-case-scenario, the alcohol absorbs enough water to separate from the Gas, and the mixture corrodes, grows stuff and doesn't burn.
Texaco claims that E-10 will keep for a year if it's kept in an airtight (metal) container. I add a dose of Sta-Bil and keep it for up to 2 years without problems.
E-10 causes no problems whatsoever if it's fresh.

 

[sachsmo]

Read the ingredients. Most octane boosters are alcohol.
E-10 won't cause any problems at all if you use fresh gas, or almost fresh gas that had a stabilizer added when it was fresh. The only problems with E-10 occur with old gas stored in a humid environment. In a worst-case-scenario, the alcohol absorbs enough water to separate from the Gas, and the mixture corrodes, grows stuff and doesn't burn.
Texaco claims that E-10 will keep for a year if it's kept in an airtight (metal) container. I add a dose of Sta-Bil and keep it for up to 2 years without problems.
E-10 causes no problems whatsoever if it's fresh.

e-10 has and will cause problems on many newer saws. to get by the EPA, manufacturers had to "limit" these saws to make a passing grade.

When they were tested in the factory they were set with an eth free fuel I would wager.

If I lose a second cuttin' a cookie with higher octane (eth free) it doesn't matter to me. As long as my saws are ready to go next time I pick 'em up.

Many have no choice and millions of saws are running e-10, since I do have a choice my saws get eth free gas.

It sure do smell good too.