Little touchy tonight? I'm just trying to establish the facts. How you word it does make a difference.
More dyno action. 100 octane vs 92 octane
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Little touchy tonight? I'm just trying to establish the facts. How you word it does make a difference.
ernurse
ArboristSite Operative
That sounds a lot like my luck. Thanks for testing the fuel. I am really interested in seeing how much the 660's got. I would like to dyno mine before I have it ported and milled. Just to see the before and after.
ernurse
ArboristSite Operative
Yeah I just kinda smile when my friends ask me for a few gallons of Sunoco maximal 116oct which I run in my 17.8:1 compression snocross sled. Then they get angry when they're persistent and I say no and inform them that their stock sled likely will not run well at all on it. They can't seem to get that the fuel doesn't make the power...it only allows me the near diesel compression and super hot timing. I'm getting almost 200hp with my factory Ski-doo mxz 600x open mod. I could actually use higher octane. When jetted where I like it my EGT's are almost 1000f if im WOT for more than about 15-20seconds. Now that motor would make one mean hotsaw.
Henry G.
ArboristSite Guru
Here on the leftist coast I found a place that sells a "sports blend" of 75% 100 LL AV gas and 25% tolulene. I mix that 50/50 with 91 octane gas and my saws seem to love it. Any try that combo yet? Tolulene I believe is an octane and BTU boost.
Another benefit is the gas lasts a year and still burns fine.
Another benefit is the gas lasts a year and still burns fine.
SomewhatStock
ArboristSite Lurker
100% Correct. Adding octane alone causes a decrease in power but allows for other actual power enhancing modifications which nets an increase in power.
Ernurse,
Check the gas cans your brother is using. A few guys have reported plastic gas "cans" deteriorating and the plastic settling in carbs. It usually looks like clear snot. The cans get old, and you would never see them "aging" other then the snot in your carbs.
Just a maybe situation.
A
SkippyKtm
The Lorax, my FIL rip...
I've seen lots of "mucus looking sludge" and its caused by ethanol contaminated with water, it normally settles at the bottom of the tank/gas can making a noxious mixture capable of destroying any two stroke. Its all part of what's called phase separation, it used to be when water got into a gas can the water would settle to the bottom of the can and not mix with anything, but E10 has changed all that...:mad2:
I'm curious to see what the results are. I have an 044 ported and advanced running 210 psi + that shows no signs of detonation on the crown or chamber, ran on 92 or so AKI(our minimum octane rating here).
Sprintcar
Chainsaw Slut
Everything you ever wanted to know about octane.
Octane rating or octane number is a standard measure of the performance of an engine or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating (igniting). In broad terms, fuels with a higher octane rating are used in high performance petrol engines that require higher compression ratios. In contrast, fuels with lower octane numbers (but higher cetane numbers) are ideal for diesel engines, because diesel engines (also referred to as compression-ignition engines) do not compress the fuel but rather compress only air and then inject the fuel into the air heated up by compression. Petrol engines (also referred to as gasoline engines) rely on ignition of air and fuel compressed together as a mixture without ignition, which is then ignited at the end of the compression stroke using spark plugs. Therefore, high compressibility of the fuel matters mainly for petrol engines. Use of petrol (gasoline) with lower octane numbers may lead to the problem of engine knocking.[1]
Octanes are a family of hydrocarbon that are typical components of gasoline. They are colourless liquids that boil around 125 °C (260 °F). One member of the octane family, isooctane, is used as a reference standard to benchmark the tendency of gasoline/petrol or LPG fuels to resist self-ignition.
Octane ratings are not indicators of the energy content of fuels. (See Effects below and Heat of combustion). They are only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. Where the octane number is raised by blending in ethanol, energy content per volume is reduced. Ethanol BTUs can be compared with gasoline BTUs in heat of combustion tables.
Gasoline used in piston aircraft common in general aviation have slightly different methods of measuring the octane of the fuel. Similar to AKI, it has two different ratings, although it is referred to only by the lower of the two. One is referred to as the "aviation lean" rating and is the same as the MON of the fuel up to 100.[6] The second is the "aviation rich" rating and corresponds to the octane rating of a test engine under forced induction operation common in high-performance and military piston aircraft. This utilizes a supercharger, and uses a significantly richer fuel/air ratio for improved detonation resistance.[4]
The most commonly used current fuel, 100LL, has an aviation lean rating of 100 octane, and an aviation rich rating of 130.[7]
Higher octane ratings correlate to higher activation energies: the amount of applied energy required to initiate combustion. Since higher octane fuels have higher activation energy requirements, it is less likely that a given compression will cause uncontrolled ignition, otherwise known as auto-ignition or detonation.
The compression ratio is directly related to power and to thermodynamic efficiency of an internal combustion engine (see Otto-cycle). Engines with higher compression ratios develop more area under the Otto-Cycle curve, thus they extract more energy from a given quantity of fuel.
Many high-performance engines are designed to operate with a high maximum compression, and thus demand fuels of higher octane. A common misconception is that power output or fuel efficiency can be improved by burning fuel of higher octane than that specified by the engine manufacturer. The power output of an engine depends in part on the energy density of the fuel being burnt. Fuels of different octane ratings may have similar densities, but because switching to a higher octane fuel does not add more hydrocarbon content or oxygen, the engine cannot develop more power.
There you go. If you really want a screamer, run it on methanol, better yet Hydrazine.
Octane rating or octane number is a standard measure of the performance of an engine or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating (igniting). In broad terms, fuels with a higher octane rating are used in high performance petrol engines that require higher compression ratios. In contrast, fuels with lower octane numbers (but higher cetane numbers) are ideal for diesel engines, because diesel engines (also referred to as compression-ignition engines) do not compress the fuel but rather compress only air and then inject the fuel into the air heated up by compression. Petrol engines (also referred to as gasoline engines) rely on ignition of air and fuel compressed together as a mixture without ignition, which is then ignited at the end of the compression stroke using spark plugs. Therefore, high compressibility of the fuel matters mainly for petrol engines. Use of petrol (gasoline) with lower octane numbers may lead to the problem of engine knocking.[1]
Octanes are a family of hydrocarbon that are typical components of gasoline. They are colourless liquids that boil around 125 °C (260 °F). One member of the octane family, isooctane, is used as a reference standard to benchmark the tendency of gasoline/petrol or LPG fuels to resist self-ignition.
Octane ratings are not indicators of the energy content of fuels. (See Effects below and Heat of combustion). They are only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. Where the octane number is raised by blending in ethanol, energy content per volume is reduced. Ethanol BTUs can be compared with gasoline BTUs in heat of combustion tables.
Gasoline used in piston aircraft common in general aviation have slightly different methods of measuring the octane of the fuel. Similar to AKI, it has two different ratings, although it is referred to only by the lower of the two. One is referred to as the "aviation lean" rating and is the same as the MON of the fuel up to 100.[6] The second is the "aviation rich" rating and corresponds to the octane rating of a test engine under forced induction operation common in high-performance and military piston aircraft. This utilizes a supercharger, and uses a significantly richer fuel/air ratio for improved detonation resistance.[4]
The most commonly used current fuel, 100LL, has an aviation lean rating of 100 octane, and an aviation rich rating of 130.[7]
Higher octane ratings correlate to higher activation energies: the amount of applied energy required to initiate combustion. Since higher octane fuels have higher activation energy requirements, it is less likely that a given compression will cause uncontrolled ignition, otherwise known as auto-ignition or detonation.
The compression ratio is directly related to power and to thermodynamic efficiency of an internal combustion engine (see Otto-cycle). Engines with higher compression ratios develop more area under the Otto-Cycle curve, thus they extract more energy from a given quantity of fuel.
Many high-performance engines are designed to operate with a high maximum compression, and thus demand fuels of higher octane. A common misconception is that power output or fuel efficiency can be improved by burning fuel of higher octane than that specified by the engine manufacturer. The power output of an engine depends in part on the energy density of the fuel being burnt. Fuels of different octane ratings may have similar densities, but because switching to a higher octane fuel does not add more hydrocarbon content or oxygen, the engine cannot develop more power.
There you go. If you really want a screamer, run it on methanol, better yet Hydrazine.
banditt007
ArboristSite Operative
In the U.S.A. we rate the octane of pump fuel as follows:
RON + MON =X
X/2 = Octane.
RON + MON =X
X/2 = Octane.
Also known as "AKI"
D
Deleted member 83629
Guest
in a stock engine running 93 octane E0 i noticed it is noticeably cooler running while using it for 3 hr than if i was running 87. so i use high test in my hand helds. im sure with them running a little cooler is gonna help extend engine life im not sure if it helps out on power and gets rid of detonation in my saws.
