It depends on how the car is set up, alot of places sell the biofuel pre mixed which people use in flex fuel cars. ( big in brazil)
E85 is an alternative fuel blend made up of 85 percent ethanol and 15 percent gasoline, hence the name “E85”
in the united states most the flexfuel cars or mix are only 10% ethanol which everyone calls "gasohol". but yes you can set the car up similar to a flexfuel car and run gas and e85, I personally know several guys on here that run aem ems in their evo with a e85 and gas tune , and have a toggle switch for on the fly map changes if they can not get to a e85 fueling station. Anything thing that I mod anymore will be e85 and gasoline. Good luck on your search and fuel build, personally ive seen alot of the big turbo inline 6 cars make crazy numbers on e85 compared to pump gas , its a win win type thing.