What's the Audi S4 oil type?

All Audi S4s aren't created equal: You have different engines through the various model years, so I'll give You some general advice on these cars. First, You'll typically want to use a synthetic over a conventional for them; You can use a blend if You wish, but from a performance standpoint, synthetic's going to really work out better for these engines. Now, typically, You're going to find SAE 5W-40 installed out of the factory, and that's going to be what You should keep using most the time. However, You can go with 5W-30 in a pinch, and You can also go from 0W-30 to 10-40W, varying for the climate You're driving Your Audi in.