Octane rating has no effect on flame speed. In fact a faster burning fuel would have a higher octane rating as detonation takes time and the faster you can complete combustion the less chance you will deotnate.
Klotz 100 octane race fuel
- Thread starter carhartt
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I don't doubt Dave's results. This is because guys use stuff like Sunoco 110 or Cam2 from the pump which sucks for two strokes. AV gas has the same problem. For a two stroke you really need to use a fuel that has a suitable distallation curve.
Magnum783
ArboristSite Guru
I hate to bring up and old thread but I must. So is the common consensus that 100octane is not needed?
It's not needed at all.
Magnum783
ArboristSite Guru
Ok I see that Brad and since one the saws it will be run in you did. I too am in an area where non ethanol fuel is hard to come by is it a better alternative than ethanol fuel.
It's not going to hurt anything. If you're running it to away from ethanol, that's fine.
Magnum783
ArboristSite Guru
Now second question Brad, 110 octane or 100? My thoughts for the higher octane is I live at 6200' and often times run saws at ~9000'
Don't go any higher in octane than necessary.
Magnum783
ArboristSite Guru
I will see if they can get 100 vs the 110 they carry. Are you still able to get no ethanol in Ohio.
Yes. There are quite a number of places. Prices vary wildly though, so I end up driving about 45 minutes each way.
this is abut as close as it get to a fuel thread....keep in mind 110 Sunoco race fuel for instance is leaded and lead is a type of poison and is bad for you....yes it does sell nice be it comes with a price. Im going in farther than I want to but....I run the 92-93 unleaded srf/brigs canned fuel and that gives me the shelf life I want reasonable octane rating and Im not huffing as much lead...for work I am around 110 leaded with historic race engines so I have wanted to limit my exposure...
good luck
good luck
Magnum783
ArboristSite Guru
I was reading all that last night, vp makes a fuel call c20 which in not leaded and not oxygenated thinking of checking with my vp
Supplier to see what they have and can get. I would really like to get away from the fuel at the pump. Even though it says no ethanol I have smelt it (so I thought) a few times. With as popular as ethanol is getting out here it hard to believe they can always get non ethanol fuel.
SEF94 is what you want.
Russ Melampy
ArboristSite Member
I thought that octane, by definition, was a fuel's resistance to ignite. The higher the octane the longer it takes to ignite, I think. Burning a higher octane fuel than required (to prevent pre-detonation or pinging) is simply a waste of money and may cause carbon build up over time, which then reduces the volume in the combustion chamber, raising the compression ratio, and then REQUIRES the use of higher octane.
If I may share some insight from many years of fine tuning MOTOX 2 stoke motors. For most part stock motors will preform well with 87 octane fuels at sea level provided they are adjusted to proper mixture levels. A super modified saw motor perhaps could come up to a 10 to 1 compression ratio. Because of intake and exhaust mods that are more efficient thus raising the compression level. The higher the octane the slower the burning of the fuel occurs. When the compression level is higher than 8 to 1 the fuel tends to ignite quickly thus causing pre ignition. The higher the altitude the less air means less compression. So less octane is needed. Most communities are at least 1500 feet above sea level so for most part 87 octane is perfect. When I was hired to tune some very exotic snow mobile engines I was shocked to see other competitors making basic errors at how this principal works. Above 6 and 7,000 I would statically advance the timing 4 to 9 degrees and be rewarded with performance close to that of sea level. I usually did not ever need fuel higher than 105 octane. When using higher octane fuel things can happen very fast thus ruing you otherwise perfect day. I would be surprised if anybody has a saw that exceeds 9 to 1 compression level so if you are concerned go buy some 92 octane premium and consistently mix it and enjoy the day. I have run all kinds of alcohol motors and have discovered that they are a real hand full. Ethanol in a small amount is a great thing to keep your fuel clean and dry. However it needs to be consistent and properly adjusted for. I use to take AV gas and mix it with other fuel to raise octane level since it does not have to meet normal EPA requirements. The lead is a great octane booster, tricking cheap fuel into thinking it is race bred nitro. The lead in AV gas coats the cylinder when mixed in just the right amount and will make rings and cylinder last almost forever, but unless you have an airplane it can be hard to get. However good 2 stoke oil coats the cylinder as well and is light years ahead of oils just a few years ago. Thanks
Is there any difference in the chemical fuel make up of the different non ethanol fuels? VP, Tru Fuel, SEF, Klotz, Stihl, Husqvarna, etc.... I don't mean octane ratings but just the qt. shelf storage fuels. I have ordered the Tru Fuel for customers but never used it myself. The customers claim to like it.
Agent Orange
Hacktastic®
Which oil do you mix with race gas?
AV gas does not have oxygenated crap and is designed for very long term storage.
Fun thing additives like ethers/MBTE react to form peroxides. Peroxides are reactive and will harm plastics/rubber, also when concentrated become explosive.
The alcohols just form scum and/or breed microrganisims that put the snot in your carbs/fuel system. It don't eat rubber as bad as ethers/peroxides.
It would be intresting to see the compostion profile of AV gas vs E-free and corn-fuel. Anybody have access to a GC/MS? Not me anymore.......
No, it's a measure of a fuels resistance to detonation aka abnormal combustion.
There isn't any truth to the rest of the statements in your post either,although many people believe these to be facts.
