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high octane

Post in 'The Gear' started by shawn6596, Oct 10, 2013.

  1. shawn6596

    shawn6596 New Member

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    I still have 8 gallons of 110 octane left over from race season(the purple stuff). I was thinking of mixing some up for my 850 promac. Anyone have any thoughts on this?

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  2. pen

    pen There are some who call me...mod. Staff Member

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    In my experience, if an engine isn't high enough compression to take advantage of the octane, you aren't gaining anything other than using it up.

    pen
    jharkin and BrotherBart like this.
  3. Jags

    Jags Moderate Moderator Staff Member

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    I wouldn't use it in the saw. It was never designed to run that stuff. Mix it a couple gallons at a time with an 87 octane fuel up for your vehicles. You will end up with a 90-93 octane mix (depending on size of tank).

    It ain't worth knocking a hole in the top of your piston.
  4. JOHN BOY

    JOHN BOY Minister of Fire

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    I even doubt you'd really gain anything at all ..
  5. rowerwet

    rowerwet Minister of Fire

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    I run 100LL in all my small engines. I don't think it makes them any more powerfull.
    It does completely avoid the ethanol garbage, cost me nothing, and smell awsome!
    cwill likes this.
  6. pen

    pen There are some who call me...mod. Staff Member

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    I do miss the smell of good gas. When at a car show, and notice it, I've had good luck asking the driver what sort of plane he flies, and have been told several times if I wanted any aviation gas for the generator or similar, to just stop by! In the other cases, I've heard, "naw, my buddy flies"

    pen
    rowerwet likes this.
  7. dznam

    dznam Member

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    I did the same thing last season with my leftover 110. Used it in my 372xp, 5100s, Husky brush saws and without exception they all ran like crap on race gas. Started very hard, wouldn't idle and poor acceleration. Mixed it down with 87 (around 4:1 87 to 110) and everything ran fine and I still got some of that "race gas exhaust" smell. Since octane essentially controls the burn rate of the gas, my theory was that the race gas simply wasn't "explosive enough" for the 2 stroke motors. Just my experience.
    pen likes this.
  8. rowerwet

    rowerwet Minister of Fire

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    the lead in avgas slows down the flame front, without lead high octane isn't what the motor is designed for.
  9. Mykayel

    Mykayel New Member

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    From a pure 'technical' standpoint, the higher the octane, the less energy the fuel contains per gallon. Theoretically, if you run higher octane gas in your car you will get worse gas mileage than if you would have run 87 octane. And the higher octane fuel is less prone to detonation (i.e. it doesn't burn as well) which is why it is required for higher compression ratios (think about diesel engines, they have 30:1 or so compression ratios and make a lot of power/torque but lighting diesel fuel with a match isn't like with gasoline). So it really isn't a surprise that running 110 octane gas in an engine designed for 89 octane would be hard to start and run like crap. We just associate higher octane gas as the "premium" gas and therefore think it should have more power and somehow make our normal engines run better which is not the case.
    BrotherBart likes this.
  10. shawn6596

    shawn6596 New Member

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    I just wondered what it would do. Also I love the smell.
  11. Bigg_Redd

    Bigg_Redd Minister of Fire

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    Same here. While higher octane in and of itself may do little for the average low compression 2 stroke engine, it has other advantages that make it worthwhile IMO. In addition to the aforementioned, the other advantages include - quicker revving, easier starting, zero carb-gumming, and indefinite shelf life.
  12. Bigg_Redd

    Bigg_Redd Minister of Fire

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    What manual are you reading?
  13. cwill

    cwill Member

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    Same here. Have had zero issues with it and love the fact that i can mix it up and forget about it till I need it. When I need more I just run down to the local small airport and get more, It's pay at the pump and usually nobody is there.
  14. CenterTree

    CenterTree Feeling the Heat

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    How do you get free fuel???
  15. rowerwet

    rowerwet Minister of Fire

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    work for a company that sells it, per faa regs the trucks and tanks must be sumped daily, the guys who sump it leave the buckets for me. I share it with anybody I know who wants it.
  16. shawn6596

    shawn6596 New Member

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    If I were you I would be figuring out a way to run it in my truck

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