Almost all gasoline now has some ethanol in it. Our Exxon and Mobil branded gasoline currently contains up to 10%. Gasoline with 10% ethanol content is known as E10, and with 15% ethanol it’s known as E15. Ethanol flex fuel (formerly known as E85) has between 51 and 83% ethanol with the remainder being gasoline.Click to see full answer. Hereof, what gas is ethanol free?The short answer is, no, ethanol-free gasoline is not bad for your car. Most cars today can run on ethanol gas blends up to E15 (15% ethanol) and on non-ethanol gasoline. And flex fuel vehicles can handle up to E85 (85% ethanol) without a problem.Likewise, does premium gas have ethanol in it? Premium gas doesn’t provide any more power or contain better additives than regular gas, and it contains the same amount of ethanol as other grades. Likewise, what percent ethanol is regular gas? 10%Does 87 octane gas have ethanol?Also, almost all gasoline in the US contains 10 percent ethanol. When you mix 10 percent 113 octane ethanol with 85 octane gasoline it increases the octane two points to the normal 87 octane most consumers use. The octane rating for E15 (15% ethanol) is 88 octane and E85 (85% ethanol) is 108 octane.