Gas Type by Car: Regular, Premium, Diesel or E85 / Bentley / Continental Supersports ConvertibleBentley Continental Supersports Convertible Gas type by year YearGas type2018Premium2017Premium2013Premium (flex-fuel E85 engine available)2012Premium (flex-fuel E85 engine available)2011Premium (flex-fuel E85 engine available) Source: U.S. EPA / DOE fuel economy data (fueleconomy.gov).