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Thread: high octain gas in stock wheeler

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    Default high octain gas in stock wheeler

    I got some "super" gas at tesoro last week so see what it would do, I drive it to and from work, and I know it gives cars better gas mielage, so I figgerd I'd give it a whack. I was searching on the internet, and it said it could actually produce less power than with regular 87 octain. My brother is a mechanic and learning to fly from the guys in our church, and I always hear them say "that oughta give it a little kick" when they stick Avgas in something.

    It seemed to have more power and it averaged 34 MPG. I have a little hotter spark plug in it. but other than that its stock.

    Its a 2005 honda rancher 450 (carbourated). it has almost 9000 miles on it. so, would it run better with "super" 90 octain gas, I know cars run better, expecialy old cars. if it has better gas mileage and runs better it would be worth the extra 20 cents.
    Eccleasties 8:11 Because the sentence against an evil deed is not executed quickly, There for the hearts of the sons of men among them are given fully to do evil.

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    Moderator LuJon's Avatar
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    Octane refers to the gasolines resistance to spontaneous ignition. Put another way it is a measure of the fuels resistance to detonation. Unless you increase the compression of your motor, pressurize your intake with a turbo or add an oxygenator to your intake (nitrous) then you are wasting money. If 87 octane does not cause predetonation then there is no need for a higher octane fuel.

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    Could I take the nitrus kit offa my brothers truck and put it on my wheeler? lol
    Eccleasties 8:11 Because the sentence against an evil deed is not executed quickly, There for the hearts of the sons of men among them are given fully to do evil.

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    Member Grayling Slayer's Avatar
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    Higher octane will do nothing for a stock 4 wheeler. If you want to add something I would recommend half a bottle of heet in the spring and fall.
    "I'd rather be fishing!"

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    I'll second what LuJon said--you'd be wasting your money putting higher octane gas through a stock motor.

    SOME cars designed to run high-test fuel have electronics which sense the fuel's octane/detect engine detonation, and adjust the engine's performance accordingly to take advantage of the higher octane (or, conversely, slighly detune the engine's performance when running lower octane). Your carbureted Honda doesn't have that capability.

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    Quote Originally Posted by Grayling Slayer View Post
    Higher octane will do nothing for a stock 4 wheeler. If you want to add something I would recommend half a bottle of heet in the spring and fall.
    I do that every couple months, does it add power or just clean things up a bit? The only reason I need power is we pull disks and tillers with our wheelers.
    Eccleasties 8:11 Because the sentence against an evil deed is not executed quickly, There for the hearts of the sons of men among them are given fully to do evil.

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    Member AKDoug's Avatar
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    Get a tractor

    I have taken part in dyno testing of snowmachines using various grades of fuel on a machine designed for 87 octane. Believe it or not the machine lost almost 10 hp (110 hp vs. 120hp) when using 87 octane vs. 100LL avgas.
    Bunny Boots and Bearcats: Utility Sled Mayhem

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    Moderator LuJon's Avatar
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    Efi or carbed sleds?

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    4 cy or 2 cy?

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    Member AKDoug's Avatar
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    Carbed two stroke. '98 RMK 700. Yes, we jetted it and took the best numbers of each octane available. We also tested three sources of 87 octane fuel, but only one source of 100LL.

    I realize that it isn't exactly the same as a 4 stroke, but the physics stay the same. If you don't have the compression to use high octane fuel, you won't realize a gain in HP.
    Bunny Boots and Bearcats: Utility Sled Mayhem

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    Member alaskabliss's Avatar
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    Not sure you guys are 100% correct about high octane fuel. Even if y ou don't have high compression pistons, the high octane fuel gives you a slower burn that allows all the fuel to combust, where 87 octane burns fast and explosive and not all of it is burned. Might not get much power out of high octane, but it could increase milage...

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    Too many asleep in high school physics.

    1) When you compress a gas it gets hot.

    2) The more you compress it the hotter it gets.

    3) The more you compress the air/fuel mixture (a gas) in a cylinder, the more power you get out of it (to a point) when you ignite the mixture.

    4) The higher the octane rating of the gasoline, the higer the temperature before the air/fuel mixture ignites on its own.

    So, if you want more power out of the same size engine, one of the things you do is increase the compression ratio. But then you need more expensive high octane gasoline to prevent the fuel from going off on its own and not from the spark plug (which can damage the engine). Since most people complain enough about gasoline prices as is, manufacuters design most of their engines (lower compression) to run on less expensive lower octane gasoline. Putting high octane in a low compression cylinder does nothing to increase power - you're just burning more expensive gas.

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