Sorry to be picking up thiis old thread, I have a Lifan 250B which the dealer told me to use 91 fuel, well after running in it would not do more than 60mph and lumpy with it.
Now i'm using 95 gasohol, what a difference 70+mph and much , much smoother and livelier. English manual(which i have now) says minimum 93 fuel.

Cheers

Quote by: Radnoc

Sorry to be picking up thiis old thread, I have a Lifan 250B which the dealer told me to use 91 fuel, well after running in it would not do more than 60mph and lumpy with it.
Now i'm using 95 gasohol, what a difference 70+mph and much , much smoother and livelier. English manual(which i have now) says minimum 93 fuel.

Cheers

Research Octane Number (RON) is a world wide grading system and RQ-93 (as described in the Lifan LF250-B manual) doesn't necessarily have to mean 93 Octane.

As you increase your altitude the octane requirement decreases 1 to 2 octane per 1000 meters elevation. This is because the density of the air is reduced or there is less air available for your engine to burn.

The higher the altitude, the richer your engine will run, making it necessary to re-jet the engine or adjust the throttle needle in order to lean it out. The fuel volume remains the same and the air volume goes down. The engine makes less vacuum at the carburetor too and the air fuel ratio becomes richer due to the decreasing air to fuel volume.

When the temperature goes up, the air density decreases, thus you have less air available for combustion and your air fuel ratio becomes richer. The same works in reverse. As the temperature gets colder, you end up with more air per cubic foot, the engine will run leaner.

As the air density increases, your engine will lean out. As the air density goes down, the engine runs richer.

When the humidity increases like on a hot tropical Isan day in the raining season or at sea level, octane requirements decrease.

The formula goes like this...for every one gram of water increase per one kilogram of dry air the octane decreases by 0.25 to 0.35

Gasohol is bad for your engine DON'T use it.

Quote by: ISO

Gasohol is bad for your engine DON'T use it.

With gasohol your mileage also sucks

Actually you can get the same performance out of 91 Gasohol as you get from 91 Gasoline, or you can get the same performance from 95 Gasohol as you get from 95 Gasoline.

The solution is to adjust the ignition timing, ethanol is more flammable and burns much faster than benzine. For that reason the ignition timing should happen a fraction of a second later. With some combustion engines 'especially the older one' the combustion spark happens before the piston fully completed its compression cycle. When you run benzine/gasoline this is no problem because before the whole mixture of air and fuel is lighted the piston is ready to travel down in the power cycle... with ethanol added to the fuel (the more ethanol you add to the fuel the faster the air-fuel mixture will explode).

Because gasohol explodes faster and more violent, it can damage some engines... theocratically with some engines the combustion could happen when the piston is not ready to travel down.

With regular gasohol in Thailand the added ethanol is only 10% which will not effect the engine that much, still if you decide to only run gasohol you could start tuning the carburetor and your ignition to get it really right and start saving a good amount on fuel cost.

For the people who know a thing or two about the flammable range (explosive range) of gas or vapor.

Benzine has a 6.65 UEL/UFL rating.
Ethanol has a 19 UEL/UFL rating.
“UEL/UFL = Upper Explosive or Flammable Limit”

People who say that Ethanol fuel is more difficult to ignite are right....
Benzine has a 1.35 LEL/LFL rating,
Ethanol has a 3.3 LEL/LFL rating.
“LEL/LFL = Lower Explosive or Flammable Limit”

But we not burn 100% benzine engines, the fuel gets a few additives, one well known added substance is octane... which is added to lowers the moment the fuel ignites. So basically when we compare gasohol and gasoline together the differences between the two fuels is very very small.

Maybe the question about E10 soon will be obsolet, because when I follow the discussion in Europe and the USA then it looks like that E10 will become to an end.
Now in Germany the asked question is: One time a fill up the gastank or have food for one year?