I was thinking, my moped say to run a hi octan gas. Well I heard that E85 is about 105 Octan. Any thought on this? This hi of gas will more than likely kill my motor, right?
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Story short: it can be done, jetting your carb right will be the biggest issue. Air/fuel ration for booze is much higher than for gas, around 8:1, it won't make you go any faster, alcohol is only 90% the effieciency of gas. It''l probably run alright for a while until the rings wear out and you start getting massive blow by
i doubt it'll wear your rings faster. if anything your engine will last longer. it burns cooler than gasoline. with the right tuning you can make more power on ethanol. you can run more timing.
but you'll need to jet richer and you'll see an average loss of 20-30% fuel economy. if you get 100mpg now, you'll see 70-80 on E85.
You will have to check you jetting for sure, I think that E85 actually runs something like 11:1 stoichiometric, maybe a little richer, but I could be wrong. the other thing that you'll have to check is whether or not 2-stroke oil will dissolve in it. To make it work you might have to run castor oil or somethin.
If you run that stuff you will lose economy but you will actually gain power because even though Ethanol has fewer BTU's you're burning more of it so it adds power.
you should run the lowest octane you can in ANY combusion engine without detonation. the higher the octane, the harder to burn. in a low compression this results in an incomplete burn and equivalent if not worse performance. if you really want to run it and see an improvement mill the piss out of your cylinder head until you get a compression ratio of about 16-1 and then youll have a fun ride. otherwise, dont bother.
One thing to add:
I was reading about a Briggs and Stratton alcohol conversion (for karts), and the article explained how you needed about twice as much fuel vapor exiting the carb to run properly (sounds similar to the jetting suggestions above).
The other thing that the article mentioned was that you had to run the engine dry; close off the fuel, and run the machine 'till there is no fuel in the carb or cylinder. The author also suggested that you then hook up a small bottle of normal fuel to cleanse the alcohol from the system, but that sounds like a lot of trouble (especially since you'll be pumping in twice as much as you need).
I believe that if you _don't_ do this, the alcohol will eat at the seals and gaskets. I'm considering building an alcohol engine, and part of what I'm planning is to have a small reserve tank of gasoline to use when shutting the machine down.
The above advice is for methanol. Ethanol is a little gentler to seals and metal parts.
Not much, but enough.
Indeed, kart race gas is methanol.
I'll take toehead2's gentle ethanol advice as law 'till I have a chance to tear down an engine run on alcohol.
yeah.. we are forced to buy 10% here in milwaukee and it eats the needles out of carbs like crazy, i'm sure e-85 would be a bit worse, but it wont hurt for short term.
the only way you'll make more power is more aggressive compression and higher rpm's but if done right, you can really slam it.
brandon E (soux falls)'s brother has a 50/50 stock cylinder puch that runs e85.
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