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fishhuntcutwood said:Along with the "Dean" thread, and some 056 Kid threads, this may be one of the longest and most disputed threads ever!
It's been hashed to death!
Jeff
Amen! :bang: :spam:
fishhuntcutwood said:Along with the "Dean" thread, and some 056 Kid threads, this may be one of the longest and most disputed threads ever!
It's been hashed to death!
Jeff
jimbo1490 said:It's spelled toluene, pronounced tall-you-ween (sorry for the mis-spellings :^). You are talking about the two-stroke stone age when you mention the 60's. Purpose made two-stroke oil was uncommon back then. Mostly people used motor oil (four stroke, OK with lead) at a fairly rich ratio, like 16:1 as recommended, or castor oil. By the late 60's and into the 70's, purose-made two-stroke petroleum and synthetic oils were available, firstly to the boat insustry. At that time, Amoco developed a lead-free high octane fuel marketed primarily to the boat crowd. All the boat engine manufacturers recommended it. We used to call it 'Amoco white gas' as it had no dye color. With the exception that it's now 93 instead of 95 octane, that fuel is essentially Amoco Ultimate, which was always lead-free, even before gov't mandates.
It's worth mentioning that 100LL is rated for octane number by 'research octane' only while all auto fuels are rated by the average of research ond motor octane numbers. This makes the octane rating of 100LL 3-4 points higher than it would be if the R+M/2 method was used. So Amoco Ultimate is actually within a couple of points of 100LL, both measured by the same method.
Jimbo
Wood Butcher said:Man I don't know whether to stick my finger in the fan blades here or not!
What the heck, you only live once......
first off, I'm a commercially rated pilot (single and multi) and also a certified flight instructor (18 years now I think), as well as being a certified master auto mechanic, and also worked at a Stihl dealership, though I'm not certified by them in any way. Oh yeah, also have co authored 2 books on automotive electronics and electrical systems. I don't say that to say my opinions are worth any more than someone elses, but that I have had a rather morbid relationship with both aviation and chainsaws over the past few decades. That and a buck can get me a cup of coffee, except at starbucks.....
I see a few things not discussed yet, the main one being the purpose of an octane rating. In a cylinder we want the fuel to burn and not detonate. Detonation occurs when excessive heat and pressure in the combustion chamber cause the air/fuel mixture to autoignite. This produces multiple flame fronts within the combustion chamber instead of a single flame kernel that expands outward from the spark plug as designed. The Octane rating simply measures the resistance to detonation. In general, a lower octane fuel will have more energy than a higher octane fuel. You would not notice it in a saw but a car, everything else being equal, will get better mileage on 90 octance fuel than on 120 octane fuel.
Operating environments have nothing to do with it really, unless you either have poor design or physical blockage that allow cylinder head temp to go above design specs. If you want to get technical, the temperature drops by 4.5F every 1000 feet, so even at 10,000 feet it is only 45 degrees cooler than on the ground. (a kinda cool formula to use here, is when they give the dewpoint temperature during the weather broadcast, take the current temp, subtract the dewpoint, divide it by 4.5 and that gives you the height of the cloud bottoms outside in thousands of feet) .
Anyway, what I'm trying to say is that IMHO 100LL is one of the better fuels for 2 stroke engines, use it if you can get it. If you show up at an airport with a 5 gallon can and they don't want to sell it to you, go to the next airport because they are full of it. The ONLY objection someone can give is that since there has been no road tax applied to it, you cannot use it in a vehicle driven on the street. If you tell them it is for off road use only they cannot argue with you. As has been pointed out, a place to get it for free is from the line trucks that fuel planes, after they are done gassing up a plane they stick the fuel nozzle in a funnel, and eventually the sump fills up and they have to dispose of it. Be aware there will be water in this fuel! Let it sit in a can for a day at least, a few days is better, and either carefully decant the fuel or siphon it down to the last 6" or so. I'm a cheap bastard so I'll pour the last into glass 1 gallon jugs and always let it settle for a day at least, then you can see the water and you can carefully pour off the gas on top.
Now, the other thing to do is see if you can get the jet fuel, which is basically kerosene. The best use I have found is that it is the best fuel for salamander heaters, burns much cleaner than kero or diesel.
Anyway, my points again:
1) 100LL is good for saws
2) Will it give them "more power"? maybe, maybe not. Most likely not unless there were ignition issues with that individual saw.
3) Octane, to be blunt and crude, does not relate to "more power", it relates to "resistance to detonation". Ignition timing also relates to detonation and ignition can be advanced when using higher octane which may result in higher power output but that is not what is being discussed here.
4) You can legally buy aviation gas and use it for anything except a vehicle driven on a public road.
I think that's the end of my rant, here someone else take this dang soap box!...
Disclaimer- It is now 1am and I reserve the right to make corrections tomorrow if I read this and I look at something and wonder what the heck was I thinking when I wrote that!.......
Crofter said:My friend had an experimental plane with a rotax. there was no stipulation to use Av Gas, but they warned about any alcohol. There was a test to check for content by mixing a measured amount of gasoline with a measured amount of water and see what the net sum was. 8 0z of each adds up to less than 16 if there is alcohol presence as it has a great affinity for water and somehow slips it into the mixture which leads to separation problems with the oil premix. The previous owner deadsticked, damaged and sold it. My friend had it quit twice on approach and dead sticked it sucessfully. Apparently long approach with forced windmilling with no load with closed throttle and little charge was leading to icing. It was a flying boat type hull and not too forgiving. It didnt like cool fall weather. Aviation gas might have been better. I had a few flights in it, but I dont care too much for the reliabilty of a snow machine engine in a plane. To make a long story short, gasoline is not all the same and if you are at a critical border for icing, seizing, freezing, or vapour lock, something different might be better medicine than cornerstore generic.
caporal30 said:"jet fuel" this maybe another interresting topic if someone has ever used any in chainsaw??????
caporal30....if you are talking about "jet fuel" this maybe another interresting topic if someone has ever used any in chainsaw??????[/QUOTE said:Jet fuel, A and B is basically diesel, and there's a thread on diesel in saws floating around the board right now. If you're gonna do it, stick with avgas. Jet fuel and avgas are completely different things, and not interchangeable.
Jeff
fishhuntcutwood said:Jet fuel, A and B is basically diesel, and there's a thread on diesel in saws floating around the board right now. If you're gonna do it, stick with avgas. Jet fuel and avgas are completely different things, and not interchangeable.
Jeff
rupedoggy said:Wood butcher, I thought the description you made of the mixture auto igniting was called pre-ignition not detonation. I learned detonation was caused by an octane that was too low, for the compression of the engine. Can you explain these terms for us? Thanks. Mike
Its not. A diesel engine uses compression to ignite the fuel air mixture. The resulting combustion is not detonation.Detonation is simply diesel engine operation.
fishhuntcutwood said:Jet fuel, A and B is basically diesel, and there's a thread on diesel in saws floating around the board right now. If you're gonna do it, stick with avgas. Jet fuel and avgas are completely different things, and not interchangeable.
Jeff
bwalker said:I do not think that Kerosene and Jet "A" are identical. I base this on the fact that they smell and look differant from what I have seen.
Jet A, Kero, and #1 diesel are all simular, but not the same.
Joseph said:"The most common fuel worldwide is a kerosene-based fuel classified as JET A-1.
Exactly.The fact that is says "kerosene-based" and not just "kerosene" would be indicative that they're not identical.
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