Is e10 gas the same like 91 supreme gas? I use 94 supreme?

Apples and Orangutans, Octane is essentially a measure of how much pressure it can handle without exploding too fast. Ethanol content is percentage of the fuel made from vegetables. The vegetable fuel is a strong solvent that can be corrosive to some gasket materials, and ethanol absorbs moisture with can cause corrosion to iron containing engine parts. The solvent can also clean deposits in the fuel system, if the vehicle is not being used much the fuel system can become contaminated from previous build up.

Almost all fuels in the US are now e10, some States require it, most refiners ship the same blend to multiple States, so they blend it all to simplify ditribution. Only a few States specify that high octane fuel can be ethanol free.

E10 is 10% Ethanol blended fuel. It's not 'normal' gasoline

E10 means it's 90% gasoline, 10% ethanol. E10 does not tell you the octane rating of the fuel.

Where I live, E10 is only used on 87 and 89 octane fuels. 91 and higher octane fuels are straight gasoline, not blended fuels. Where you live may be different.

No, not at all. Both 91 and 94 are probably different types of E10 gas.

When you see gas described with the letter E followed by a 2 digit number its a blend of gasoline and ethanol. The E stands for Ethanol , and the number stands for the percentage. So E10 is simply a fuel blend consisting of 90% gasoline and 10% ethanol.

In the USA, almost all automotive gas sold at stations to the general public is E10. If you look at the pump next time you fill up, you'll probably see a sign saying that the fuel contains up to 10% ethanol.

There is some push toward using higher percentages of ethanol (and thus less gasoline). Some people want to move the standard to E15 which would simply be 85% gasoline and 15% ethanol.

Many new vehicles are designated as "Flex Fuel vehicles " - these vehicles have sensors which detect the ethanol percentages, and then the engine computer automatically optimize the fuel/air ratios and spark plug timing for any gas/ethanol mixture up to E85.

Octane rating (87/89/91/94 etc) is something entirely different - its the ability of the fuel to resist premature ignition. In a high compression ratio engine, the fuel can actually ignite too early - caused simply by the heat and pressure instead of the spark plug. This is incredibility inefficient and can actually damage the engine. Engines with higher compression ratios require fuel with a higher octane rating to prevent this. If you are using an octane rating higher than what your car's manufacturer recommends then you are wasting money.

e10 is 10% ethanol and can be 87, 89 or 91 octane. Avoid higher ethanol content than 10%. Read the label on the gas pump. Read the fuel requirement stated in your owner's manual. If you follow the manufacturer's requirements, you don't need to understand the chemistry of the fuel.

e10 simply refers to the gas being 10% ethanol and is not equated with octane grade.

It's none of those things. The E (number) means how much ethanol is mixed into the gas. Every car can use e10 which is 90% gas and 10% alcohol. The octane rating is the number from 87 to 93. Most cars run on regular 87 octane. Premium is NOT better but some engines require it.

Ten per cent of the gasoline is ethanol.

e10 means fuel with 10% alcohol (ethanol). It may mean "Up to 10%" as the crossed out numbers mean do not use fuel with higher alcohol 20 - 85%.

The 91 / 94 octane is another thing, use which you want but 91 is fine.