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AlisoBob
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Post by AlisoBob »

britincali wrote: Never did understand this, 2 x the fuel = 2 x the oil so shouldnt it be something like 70 : 1 ?
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Kuma
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Post by Kuma »

A little off topic on the Alcohol but here's my $.02 on what I know.
Al uses 2X as much as gas but doesn't burn all that. an alcohol motor should be able to run cooler because of that, much of the alcohol goes unburned out the exhaust taking heat out of the motor with it.
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AlisoBob
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Post by AlisoBob »

When a liquid evaporates, its molecules convert from the liquid phase to the vapor phase and escape from the surface. What drives this process is heat. In order for the molecule to leave the liquid surface and escape as a vapor, it must take heat energy with it. The heat that it takes with it comes from the surface from which it evaporated.

Now Alcohol has a higher cooling effect than gasoline by volume, and now multiply that by two times as you need twice as much alcohol to have the correct air / fuel ratio. These two reasons combined is why alcohol motors run "cooler" than gasoline motors.

The BTU of alcohol is less than gasoline by volume, but again, you burn twice as much of it so the effective BTU is greater than gas.

Nitromethane has a BTU less than gasoline too, but you can burn a shitload of it as its almost 50% oxygen by volume.
100hp honda
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Post by 100hp honda »

for curiousity sake i figured better see what cylinder pressure is before i take everything apart. aint had much ambition so this was far as i got :woot: . not bad for having stuck rings about noon and still rip up the hill until 7pm.

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Roostius_Maximus
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Post by Roostius_Maximus »

that means nothing. If you could kick it more than 3000 rpm you'd see that it likely doesnt need a ring at all. :wink:
100hp honda
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Post by 100hp honda »

fo sho gonna tear into it this weekend with a 6pak of monster at hand. hoping just relieve the bridge more and new rings. hell maybe the rings aint fuked like i first though. lost alot of cylinder pressure though so i dont know. gonna put 4 lube holes this time. extra vibes got me worried. wonder if crank wheels twisted ? crank bearings was almost new so i dont see how that could be the problem
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2strokeforever
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Post by 2strokeforever »

fo sho gonna tear into it this weekend with a 6pak of monster at hand
dont forget your anodised gas cap...
the 450 will have less power and will be harder to start, and will be heavier, but to make up for it it will require more maintenance.
4stroke=dead fish
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