Audi has been introducing Americans to solid German auto engineering since 1969. Today its cars use engines that contain impressive automotive technologies such as turbochargers, gasoline direct injection and turbo-diesel technology. However, the added performance and efficiency these improvements bring require paying some close attention to your Audi's fuel requirements.
All new 2010 to 2011 Audi models sold in the United States that do not bear the marking "TDI" require premium gas. The 2001 to 2004 Audi A4 can run on regular 87 octane gas, but experts stills recommended using premium. A quick look at the inside of the fuel tank door can confirm what gas is required for older Audi models. Premium gas is usually 91 octane or higher.
Audi has produced many diesel models in the past and pioneered the modern "turbo-diesel" engine, first introducing it in 1989. In North America, owning an Audi with a diesel engine means filling it with low-sulfur diesel fuel only. Filling it with gasoline will severely damage the engine. Most modern diesel-powered Audi cars have a "TDI" badge somewhere on the rear of the car.
No recent Audi models sold in America have been able to accept regular gas without risking heavy engine knocking. Knocking is caused by fuel and air particles exploding inside an engine cylinder before they reach the proper temperature. Generally, the presence of a turbocharger in an engine means it needs premium. Many of Audi's American lineup of cars use some form of turbocharger.
