What octane is best, and why

[huskihl]

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

According to a couple guys in the know, even octane booster needs added in crazy quantities to actually raise octane for a vehicle. Like a couple ounces per gallon barely changes it.

I think the “oil reducing octane” thing is blown way out of proportion. I doubt 32:1 changes the octane by .25 of a number

 

[Rich Fife]

For our 358cid restricted race motors We seen 7-11% gains on the dyno running E85. We normally run 110-112VP... our motors range from 11:1cr to 13:1cr.

 

[Rich Fife]

Found this interesting...

The oil that is added to 2 stroke fuel lowers the octane rating of the gasoline. So a higher rating is needed to maintain the required level. Since the only difference the octane RATING makes is the fuels ability to resist detonation...

 

[pbillyi69]

According to a couple guys in the know, even octane booster needs added in crazy quantities to actually raise octane for a vehicle. Like a couple ounces per gallon barely changes it.

I think the “oil reducing octane” thing is blown way out of proportion. I doubt 32:1 changes the octane by .25 of a number

i have never believed that adding 12 oz of so called octane booster is going to change the octane of my 25 gallons of gas enough to make a difference if any at all

 

[davidwyby]

i have never believed that adding 12 oz of so called octane booster is going to change the octane of my 25 gallons of gas enough to make a difference if any at all

Get rid of the ping in my sand rail. But it’s a very small tank. Like 5 gall?

 

[davidwyby]

Found this interesting...

The oil that is added to 2 stroke fuel lowers the octane rating of the gasoline. So a higher rating is needed to maintain the required level. Since the only difference the octane RATING makes is the fuels ability to resist detonation...

2smoke oil is made to burn. I think it helps make power cuz earl makes more power than gas. Besides sealing the rings better.

 

[mainer_in_ak]

I have experienced detonation towards the end of an 18 ft milling wrip, 36" bar buried, pulling .404. Pav-ported CS1201. The saw got HOT. The detonation wiped out the spark plug. Ignition timing and squish a bit too spicy for mid-grade. Midgrade 90 octane is all we get here in Alaska.

Replaced spark plug. Fresh batch of fuel mixed 32:1, I mixed 1 oz per gallon of an mmt octane booster. Never had that issue again. It raised the octane by 7 points, so was close to 91 octane, mixed up.

 

[Maintenance Chief]

According to a couple guys in the know, even octane booster needs added in crazy quantities to actually raise octane for a vehicle. Like a couple ounces per gallon barely changes it.

I think the “oil reducing octane” thing is blown way out of proportion. I doubt 32:1 changes the octane by .25 of a number

Depends on where the decimal point is on the bottle, some octane booster are only raising a fraction of the point.
Good octane booster is not what you want to get on bare skin because of the carcinogens!
I had a bottle of pure benzene once years ago. I added an ounce of it to my push mower tank, Son of gun did pick up 200 rpms and cut 10" grass like a belly mower!

 

[Woodsman]

I have experienced detonation towards the end of an 18 ft milling wrip, 36" bar buried, pulling .404. Pav-ported CS1201. The saw got HOT. The detonation wiped out the spark plug. Ignition timing and squish a bit too spicy for mid-grade. Midgrade 90 octane is all we get here in Alaska.

Replaced spark plug. Fresh batch of fuel mixed 32:1, I mixed 1 oz per gallon of an mmt octane booster. Never had that issue again. It raised the octane by 7 points, so was close to 91 octane, mixed up.

I believe you can order canned Sunoco Optima 5 or VP Racing. They have octane ratings from 95 to 112.

 

[FederalQ]

I spoke with a member of the local fire department who said they use Tool Fuel (not to be confused with Trufuel) premixed 40:1 that has an octane rating of 95. It‘s expensive and can‘t recall cost off hand. Their equipment could be used in the next hour or sit for 6 months without use.

 

[mainer_in_ak]

I believe you can order canned Sunoco Optima 5 or VP Racing. They have octane ratings from 95 to 112.

Thanks, no canned, would be too expensive. I go through about 5-6 gallons of chainsaw gas a month. Anyhow, the mmt octane booster does help.

 

[FergusonTO35]

For the casual user a premium corn free canned fuel is probably the best. I don't even use that much 2 stroke fuel but I always mix my own so I know exactly what is in it. I can afford to shoot only factory ammo but I reload for much the same reason.

 

[FederalQ]

This is from an operator’s manual for Husqvarna 61/268/272XP saws dated 3/1996.

 

[redneckhillbilly]

This is from an operator’s manual for Husqvarna 61/268/272XP saws dated 3/1996.View attachment 476718

I've heard of the older manuals mentioning a 32:1 ratio for saws above 70cc outside of the U.S, does that manual by chance mention that? I am yet to see one, but hear it mentioned quite often.

 

[FederalQ]

No it doesn’t but says to use a good quality 2 stroke oil 1:33 to 1:25 if Husqvarna brand oil is not available. And do not mix more than 1 month’s supply of fuel.

 

[redneckhillbilly]

Thanks for posting that, I have been searching to find a picture of that, one of the employees at a local shop is hell bent on lecturing me on how bad it is for me to be running 32:1 in my saws. I am going to show him that pic.

some people are soo smart its a waste of time trying to talk to them, hes one of them.

 

[huskihl]

Thanks for posting that, I have been searching to find a picture of that, one of the employees at a local shop is hell bent on lecturing me on how bad it is for me to be running 32:1 in my saws. I am going to show him that pic.

some people are soo smart its a waste of time trying to talk to them, hes one of them.

If the saw will tune for it and it’s not building carbon, there are no drawbacks.
In fact if he knew much about strato technology, he’d know that they need about 35:1 just to make up for the lack of oil/mix going through the saw due to their efficiency.

Basically, if a saw is 25– 30% more efficient, that’s 25–30% less fuel and oil going into the engine to lubricate the bearings

 

[bwalker]

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.

Adding oil doesn't raise the Flashpoint at all.
People here need to really dig into and understand what Flashpoint measures.
It also has zero to do with the quality of a two cycle oil.

 

[bwalker]

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

Some oils actually raise octane. Most have very little or no effect.

 

[bwalker]

This thread is so full of bad information I dont know where to start...