Optimal Octane?

<HTML>i was just wondering which octane grade i should be putting in my 92 tomos golden bullet ttlx. i've been putting in the highest grade i can find - 93. but is that the best choice for it? i know it's the cleanest fuel and hey it costs more so it sounds good for my ped, but i also heard that regular 87 is better. so which is it?</HTML>

RE: Optimal Octane?

<HTML>Don't know the answer technically Dave, but my friend who owns a gas station says he won't put the cheap stuff in his two stroke lawn mower! I use the high priced spread in my 11/79 PUCH and it runs just dandy.</HTML>

RE: Optimal Octane?

<HTML>According to the good people at Heeters, it's better to use the unleaded gas instead (the cheap stuff) cause it doesn't contain additives (??)...</HTML>

RE: Optimal Octane?

<HTML>Anyway you put it, the more octanes the better (specially if you have high compression ratio- new Tomos mopeds 10:1). Ignore the leaded/unladed dillema since it only makes a difference on four strokes.</HTML>

RE: Optimal Octane?

<HTML>

I would recomend not using 93 octane more than once a month. The detergents used in premium will break down the 2 stroke oil. In a four stroke this is a good thing but in a moped it can be lethal to the engine. You should try to use 87 octane as much as possible. 89 isn't too bad. Some states like Maryland allow mixed-midgrade, which is 87 and 93 mixed to get 89. This can be as bad as 93. Cam-2 can be mixed in a moped but I wouldn't do it too much and never more than 3oz. to a gallon.

john</HTML>

RE: Optimal Octane?

<HTML>hey if you won't to use the high octane i would wait a little while becouse with the gas prices are so high not many people are use the high octane gas and the high octane gas is going bad. i don't use the high octane but if you do i wait!!

bye

scott</HTML>

RE: Optimal Octane?

Man you got to find out the compression ratio your engine has. If the ratio is below 8.5 you can use 87 gas all right. If you have 9.0 and higher the 93 gas is definitely better. Some highspeed 50 cc engines have compression ratios around 12, so they run best on 95 and 98 gas. So, the compression ratio of your engine is the most important value to choose the correct fuel. Also keep in mind that feeding a low-compression engine with a high-octane fuel is a sheer waste of money and it doesn't make it run faster but is not likely to harm the engine. On the contrary, if you try to use low-octane fuel in a high-compression engine this will cause knocking (or detonation) which is going to kill the engine very soon.

Take care,

Daniel

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