When it comes to fuel for our motorcycles we discovered that a lot of myths cloud the truth. Gasoline companies like to pretend that their gasoline is better than the fuel from the station down the street. It isn't necessarily true. Your local petrol station may sell fuel refined by Shell, PTT, Chevron,BCP, Esso or Petronas. Actually most fuel in Thailand regardless with petrol station you stop is using petrol that was refined by Thaioil Group, which produces about 275,000 barrels per day. Suppliers also share pipelines, storage and other resources so they all use the same fuel. The only difference between one brand and another is the additives that they put in the refined gas – and there additives are mostly cleaners that reduce engine deposits.
There are different blends of gasoline. The typical fuels that people are familiar with are regular and premium-grade, but there are many ofter different blends – of which E10 or gasohol, E20 and E85 are the most controversial. E10 or gasohol is a blend of 10 percent ethanol and 90 percent gasoline that is sold everywhere in the country. All motorcycle manufacturers approve the use of blends of 10 percent ethanol or less in their new motorcycles. However, motorcycles will typically go 3 to 4 percent fewer kilometers per liter on E10 / Gasohol than on straight gasoline. The regular gasoline, known as benzine in Thailand is a blend of 5 percent ethanol and 95 percent, therefore the difference between gasohol E10 and Benzine is in reality about 1 or 2 percent fewer kilometers. E20 is a newly approved gasoline blend that contains up to 20 percent ethanol. Fewer than 5 percent of the motorcycles on the road are approved by their manufacturers to use E20 fuel.
E85 is a blend of 85 percent ethanol and 15 percent gasoline and can be used with flexible fuel engines, which can run on gasoline, E10, E20 and E85 or any mixture of them. Honda Thailand is the scientific leader in this area.
The current problem with using the 85 percent ethanol fuel in motorcycle engines is that ethanol this highly concentrated tends to corrode aluminum, plastic and rubber components of the fuel system. Even if the parts are manufactured by using the current available ethanol corrosion inhibitors... Honda Thailand has a PGM-FI prototype fuel injection system that has been designed and make with stainless steel parts and rubber hoses and seals that are not as sensitive to ethanol corrosion, the downside is that a complete stainless steel fuel-injection systems is about twice as heavy and a good amount more expensive.
The different grades of fuel are measured on a system of RVP, or Reid Vapor Pressure. The higher the RVP number of a particular fuel blend, the easier it is to vaporize and the worse it is for the environment. All gasoline blends have to be below 14.7 psi, which is average atmospheric pressure. Any number higher and gasoline would become a gas (vapor).
Additional not all fuel in the world is the same, E10/gasohol in north Europe will probably have more butane as an additive than the fuel you find in Thailand. Fuel in Thailand my still contain butane, but only in low quantities – of 1 or 2 percent. The environmental properties of where you live is important to what additives are added to the fuel. Thailand is a tropical country and therefore fuel companies are forced to use different fuel additives than they would use in countries in North America or Europe.