Petrol gradePetrol grade  - Petrol - Fuel and filling the tank - General maintenance - Audi S5 Owner's Manual - Audi S5

The correct grade of petrol is listed inside the fuel tank flap.

The vehicle is equipped with a catalytic converter and must only be run on unleaded petrol. Unleaded petrol must comply with the European EN 228 standard. The petrol grades have different octane ratings (RON). If, in exceptional circumstances, the correct octane rating is not available, please note the following: Your engine normally requires Super Plus unleaded petrol (98 RON) according to ⇒ Performance, weights and dimensions.

Premium unleaded fuel with 95 RON can also be used. This can, however, result in a slight loss of power under certain driving conditions.

If premium unleaded petrol is not available, the engine can be run on regular unleaded petrol with 91 RON as an emergency measure. In this case only use moderate engine speeds and a light throttle. Avoid using full throttle. Fill up with premium or Super Plus petrol as soon as possible.

Caution
Petrol complying with the EN 228 standard can contain small quantities of ethanol. However, bioethanol fuels, which are retailed under various different names such as E50 and E85, and which contain a large proportion of ethanol, must not be put into the vehicle, as this would damage the fuel system.
Even one tankful of leaded fuel would permanently impair the efficiency of the catalytic converter.
High engine speed and full throttle can damage the engine when using petrol with an octane rating lower than the correct grade for the engine.