petrol 135 octane?HIGH octane

Discussion in '2-Stroke Engines' started by juliman, Nov 12, 2009.

  1. juliman

    juliman Member

    hey guys , my father is a pilot not jets but putt putt planes, and some times he brings home some av gas, i was wondering what if i ran 50/50 avgas petrol( with correct oil ratio) in the motor since i dont have one yet i cant tell lol this is just sort of opinions, but he said that with a rich mix raw avgas is 135-140 octane and very clean, he wont let me run straight av gas in my dirtbike (4 stroke) cuz he said it will bone the valves, but a two stroke doesnt have valves and 135 octane is like racing petrol, so if i mix 50/50 what is likely to happen, will i get slightly more performance, it is probably gunna clean the engine out too lol so yer just opions and what you guys think if you ran HIGH octane petrol ( if u can call it that at such high octane it is more like racing fuel lol) this post doesnt make much sense so ill stop writing lol thanks guys


    DJEEPER Member

    you know higher octane doesnt equal more horsepower right?
  3. juliman

    juliman Member

    yer, so what will it do then... it should give a bit more power or torque or something , well at least it is a really clean fuel
  4. Ghost0

    Ghost0 Guest

    By definition a higher octane fuel actually produces less power. A higher octane rating means the fuel has a lower propensity to predetonation or knocking. The only way to achieve this is by lowering its flash point which reduces it's energy output compared to a lower octane fuel. The purpose of high octane fuel is to allow the use of a higher compression combustion chamber which is more efficient and produces more power than a low compression engine. The other added benefit is that it tends to run cooler. So for most of our low compression bike engines low octane is the way to go. The only time I would ever consider running a higher octane fuel is if I raised my compression by installing a new head or if the ambient temperature becomes really high.