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What octane is best, and why

Kiwioilboiler

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Looks to like it. That probably explains why canned fuels, designed for small engines, are often made in the low to mid 90's octane wise yet don't hinder power. At least in my seat of the pants usage. I wouldn't use cutting wood as a test median because the 1 second or less difference in cut speeds, as seen in the redbull vid, can easily come from variables in the wood and operator. Not intentional either. I'm saying that the great majority of us, if the wood was identical in every way, can't reproduce exact cut times over and over. And to me, a 1/2 a second means nothing anyway. I don't race.

And unfortunately Rogue Australia is going to be like us here in NZ soon. That is, nearly totally reliant on imported product as more and more domestic refineries suffer from the retrenchment axe.
 
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Larry B

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Silly question. Does anyone know what the compression ratio of a ms660 running 200 psi compression might be.
 

Slotracer577

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Looks to like it. That probably explains why canned fuels, designed for small engines, are often made in the low to mid 90's octane wise yet don't hinder power. At least in my seat of the pants usage. I wouldn't use cutting wood as a test median because the 1 second or less difference in cut speeds, as seen in the redbull vid, can easily come from variables in the wood and operator. Not intentional either. I'm saying that the great majority of us, if the wood was identical in every way, can't reproduce exact cut times over and over. And to me, a 1/2 a second means nothing anyway. I don't race.


I've had a stock ms660 suffer detonation the piston had like melted molten bubbles worse around the squish band area of the piston. I put pics of it up years ago I put it down to off fuel it was low octane to start with.
I don't care about cut times or any of that I struggle in summer with fuel boiling and vaper locking I think it's to do with the ethanol in it.
If I could afford to run canned fuel I'd run that here it's very pricey.
I've tried avgas it works good in my saws dare I say in my hands they feel to make more power back up to full factory spec hp running on it.
I think the problem is the cheap pump fuel here is made for new vehicles not industrial 2T's.[/QUOTE]

also as mentioned gas is essentially c7h14 and thus a blend of hydrocarbons that varies. Imho the big advantage of canned fuel, 100ll or other high end race fuels is they are consistent. They are not a blend of whatever is cheap when blending occurs. Makes it easier to keep a consistent tune and performance should be more consistent. I use 100ll simply for the storage stability. I have read it’s up to 2 years. Airplanes sit a lot and need a fuel that is stable as carb failures are deadly.
 

Bull Mountains

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I've had a stock ms660 suffer detonation the piston had like melted molten bubbles worse around the squish band area of the piston. I put pics of it up years ago I put it down to off fuel it was low octane to start with.
I don't care about cut times or any of that I struggle in summer with fuel boiling and vaper locking I think it's to do with the ethanol in it.
If I could afford to run canned fuel I'd run that here it's very pricey.
I've tried avgas it works good in my saws dare I say in my hands they feel to make more power back up to full factory spec hp running on it.
I think the problem is the cheap pump fuel here is made for new vehicles not industrial 2T's.

also as mentioned gas is essentially c7h14 and thus a blend of hydrocarbons that varies. Imho the big advantage of canned fuel, 100ll or other high end race fuels is they are consistent. They are not a blend of whatever is cheap when blending occurs. Makes it easier to keep a consistent tune and performance should be more consistent. I use 100ll simply for the storage stability. I have read it’s up to 2 years. Airplanes sit a lot and need a fuel that is stable as carb failures are deadly.[/QUOTE]
The only concern with avgas use in a saw is sucking lead fumes. And its a real concern.
 

foeke

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Lead poisoning to make your saw run better, does not sound like a sane compromise. Lead poisoning is more definitive then vapour lock.
Just don't use leaded fuels. Especially when the exhaust gasses go straight in your face.

Verstuurd vanaf mijn SM-G955F met Tapatalk
 

rogue60

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Lead poisoning to make your saw run better, does not sound like a sane compromise. Lead poisoning is more definitive then vapour lock.
Just don't use leaded fuels. Especially when the exhaust gasses go straight in your face.

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It's ok calm down I said I tried it I don't run it all the time and besides I alway cut with the wind in my face if I have a lot of cutting to do even running dirty pump fuel I don't like breathing exhaust fumes same as anybody.
 

foeke

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It's ok calm down I said I tried it I don't run it all the time and besides I alway cut with the wind in my face if I have a lot of cutting to do even running dirty pump fuel I don't like breathing exhaust fumes same as anybody.
Not meant for you personally, but for people reading your post and think, "I need that extra bit of power".

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Egg Shooter

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QUOTE="Redfin, post: 1226042, member: 159"]Found the finished car but couldnt find a vid of it running on track.

Impressive regardless.[/QUOTE]

I believe he's still working on it. There is a vid of the engine running after completion.
 
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