Can existing car engines be adapted for ethanol fuel?

Your car can safely run on fuel that is up to 10% ethanol. To run E85 which is 85% ethanol your car must be modified. It can be done but it would be very expensive to make all the changes necessary. Ethanol is a solvent and will destroy common rubber seals and gaskets used in cars not designed to run it. It is highly corrosive to aluminum and other parts in an engine. And besides, why would you want to burn ethanol. Ethanol has less energy than gasoline so your fuel mileage will drop around 20 to 30%. If you are getting 30 mpg with gasoline you will get around 24-25 with Ethanol. You will also have less power burning Ethanol. And it takes corn and other food sources to make Ethanol. That causes the price of corn to go up costing us more for food products containing corn.