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  1. #1

    can i change from av gas to premium unleaded

    hi all' im new he, so please be gentle with the newbie my Q: is can i change from av gas to premium unleaded, with changing carb set up or anything else???


  2. #2
    CHICKA WAH WAH bren's Avatar
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    Quote Originally Posted by Jetski Dog View Post
    hi all' im new he, so please be gentle with the newbie my Q: is can i change from av gas to premium unleaded, with changing carb set up or anything else???
    what are the reasons you are on av now?

    what set up do you have?

    mostly the reason for av gas is to prevent detonation

    oh and welcome to gh mate

  3. #3
    joeblo's Avatar
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    I assume if you are running avgas you are running higher compression or triple pipes with comp,it is not as easy as changing jetting on carbs,if your ski is running well do not touch anything ,my personal experience on my old triple pipe which was running 86 plus mph 1300 triple pipe porting by lowell running 150-155psi running avagas,i would not reccomend you try and change fuels as you will blow it up,list all your mods and i am sure i and others can help you out,which country do you live in

  4. #4

    please let me change my Q: about av gas

    thanks for the welcome, an replys.
    this is my reason why i was wanting to change from av gas i have been using av gas for a little while now, and i was speaking to a friend of a friend and he started tell how dangerous av gas can be cos when it is on fire it is a invisible fame. Q1: is it that true about the invisable fame when its premix ?? Q2:and how dangerous just can it be now?? Q3: and i was also told that insurance company wont cover me if i am running av gas ??


    Quote Originally Posted by Jetski Dog View Post
    hi all' im new he, so please be gentle with the newbie my Q: is can i change from av gas to premium unleaded, with changing carb set up or anything else???

  5. #5
    CHICKA WAH WAH bren's Avatar
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    insurance depends on where you are in the world and what your policy is.

    what comp ratio are you running?

    what timing?

    what pipes?

    what altitude?

    in regards to the colour of the flame, what oil are you running?

    you are not telling enough of the picture

  6. #6
    Moderator beerdart's Avatar
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    ABOUT AVIATION FUELS - Aviation gasoline (or "av gas") is blended specifically for use in small aircraft. It's also commonly used by many high performance engine owners because of it's high stated octane rating (usually 100-110) and the relatively low price compared to racing fuel. Unfortunately this fuel is not all it appears to be. Av gas octane is rated on a different scale than gasolines intended for ground level use. What is 100 octane "av", is not necessarily 100 octane "ground level". Besides this, there is also a big chemical difference. Normal ground level race fuels are made up of gas molecules that have a "light end" and a "heavy end". The light end of the molecule ignites easily and burns quickly with a low temperature flame (as a piece of thin newspaper would burn). The heavy end of the molecule is not so easily ignited, but it burns with a much more intense heat (as an oak log would). This heavy end of the gasoline molecule is responsible for the hotter, more powerful part of the combustion process.
    Small aircraft are constructed as very weight conscious vehicles. That's because their somewhat weak engines often have difficulty taking off with any extra weight. To help reduce this weight problem, av gasolines are blended with no heavy molecule end. This makes a gallon of av gas weigh substantially less than a gallon of ground level fuel. Since small plane engines turn very low rpms and produce so little power, the omission of the heavy end is not a horsepower issue. However, for high output pwc racing engines, there is defiantly a compromise in power. This, despite the fact that many pwc owners experience the desirable cooler operating temperatures that "av" gas offers. In addition, some blends of av gas will quickly separate from some oils used in premix situations. For the above reasons, we do not recommend the ongoing use of 100% av gas, and we will not prepare any "av gas" engine kits.
    Despite all this bad news, running av gas (accepting the slight power loss) is usually a better choice than
    burning down a high output engine on regular pump gas. In this situation, the best choice is usually a 50/50 mix of pump and av gas. That provides "some" heavy molecule ends for the engine.

  7. #7
    Moderator beerdart's Avatar
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    Av Gas is a common alternative to pump gas in performance applications. Because street pump gas is primarily designed to address emissions considerations rather than performance, Av Gas os iften preferred for performance applications. When choosing a fuel for such applications, here are some important things to consider.

    Av Gas is designed for low RPM engines. A typical aircraft engine does not rev much beyond 2,200 RPM. Av Gas therefore has a very slow burn speed and is typically not well-suited to high RPM engines with their much higher exhaust and cylinder temperatures.

    Since Av Gas is used in engines that typically operate at a steady RPM, acceleration and throttle response qualities are less crucial than with most racing fuels.

    Av Gas octane ratings (e.g. "100/130") are derived through different methods than octane numbers for racing and street gasolines. As an example, 100/130 octane Av Gas is generally similar in performance to a racing gasoline in the mid to high 90's octane range.

    Av Gas can work better than street gas in some performance applications because the quality of pump gas is often poor. However, in almost every case, the correct racing gasoline will provide more horsepower and torque, crisper acceleration, and cooler operation, as opposed to AV Gas. Racing gasolines are also usually less prone to vapor lock, more efficient at the atmospheric pressures and temperatures at ground level. For the ultimate performance, reliability, and maximum engine life, race gas is usually a much better choice.

  8. #8
    gp1300r ,triple pipes, 150 psi, i use yamlube.

  9. #9
    im just a bit paranoid about some of the dangers now!?, or am i just worrying about nothing?? .

  10. #10
    Moderator RX951's Avatar
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    welcome to the forum

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