i got 10 gallons of 100 octane low lead... can i reduce that to 87?
- Thread starter freezerburn
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to my (flat) engine as i believe i can get some more 100av and it could turn into long term useage.
I believe the higher octane is simply more 'knock' [pre-ignition] proof than lower octane fuel. Necessary when the compression ration is really high, which is the main contributor to 'ping' [and worse, such as 'detonation']. I'm pretty sure that using high octane fuel in an engine that does not require it [generally due to its relatively low compression ratio] there is nothing to gain and nothing to lose.
I've got a buddy who started out back in the old days in top fuel "Nitro" drag racing and now into Mototrials and the GAS GAS Tech guru - He says the higher the octane, the SLOWER the burn which is why it helps with detonation. I'm pretty sure the gain will not be noticed at all in a motor that does not have high compression or wildly advanced timing. If you were getting the AV gas cheap, run it. I pay about $7 / gal for B35 race gas (101oct) for my trials bike. I do see the need, it smoothes out the throttle response. Keep in mind, the motor on this modern competition ready trials bike is a fairly high compression 2-stroke (friggin torque monster). FYI, if you search GAS GAS USA tech and look up Jon Stoodley. He's a wealth of info on anything internal combustion...
Energy Research Corporation [in San Lorenzo] is a serious state of the art facility for fuel design. The stuff we buy can cost as much as 25 a gallon. The formula that we tend to purchase is A19-A and is in excess of 110 octane. We would use methanol but that would change the car's class and would bring on a whole new set of fuel management issues.
You cannot possibly damage a flatmotor or any other gas powered Otto cycle engine by using a fuel with a higher octane rating than necessary.
You cannot possibly damage a flatmotor or any other gas powered Otto cycle engine by using a fuel with a higher octane rating than necessary.
Well you have been misinformed as "octane rating" has nothing to do with the BTU content or the flame temperature for that matter.
You may also be surprised to learn that in the right conditions, low octane fuels typically produce more BTU per pound that higher octane fuels. The problem come in when low octane fuels detonate.
You may also be surprised to learn that in the right conditions, low octane fuels typically produce more BTU per pound that higher octane fuels. The problem come in when low octane fuels detonate.
all good points and due ly noted and appreciated.
i wont sell the AV as it is gifted to me. but good idea. also btw there is a possibility that i will be able to get more in the future.
i have heard in my research that the fuel will not get completely burned in the low comp flathead. will i lose a noticeable amount of power or is this a non issue? im not huge on power but i dont want to lose much either if i can help it.
i wont sell the AV as it is gifted to me. but good idea. also btw there is a possibility that i will be able to get more in the future.
i have heard in my research that the fuel will not get completely burned in the low comp flathead. will i lose a noticeable amount of power or is this a non issue? im not huge on power but i dont want to lose much either if i can help it.
I remember from the past that av-gas is designed for high altitudes where the air is not as dense. By itself, it's not supposed to be good to use in engines run at low altitudes (on the ground). I would think a mix of 50/50 would be fine. Being "low lead" would be a good thing for your mini bike. All of the older engines were designed for "leaded" fuel. The lead acts as a lubricant and was easier on the valve seats. Todays' "no leaded" fuels are the reason we have hardened valve seats in engines. ***I don't know if this is true, but, I've heard that the lead in the old fuels in the old engines actually hardened the valve seats, preventing the need for hardened seats from the factory.*** Now all you serious engine gurus read what I said and feel free to agree, or shoot me down on any mistakes in my info. Some of what I said could be "off" a little due to age and bad memory. Some of it may be skewed due to pain and medication. I can tell you though, if I got a good deal on some av-gas, I'd mix it, use it, and not give it a second thought. Now if you get a good deal on "jet fuel", you need to save it for your kerosene heater :smile:. Tim.