Gas Type by Car: Regular, Premium, Diesel or E85 / Audi / TT RoadsterAudi TT Roadster Gas type by year YearGas type2018Regular2017Regular2016Regular2015Premium2014Premium2013Premium2012Premium2011Premium2010Premium2009Premium2008Premium2006Premium2005Premium2004Premium2003Premium2002Premium2001Premium Source: U.S. EPA / DOE fuel economy data (fueleconomy.gov).