Originally Posted by angrypengu

Yes, but it depends on how rich the engines are fun. The 1st gen FSI Audi models on the B7 as an example ran rich AF. This resulted in significant oil shearing and thus increase in oil volatility.

Newer DI engines don't have this issue, but they all run rich and can't enter ultra lean burn mode because of the sulphur content in our fuel.This is why FSI = fuel stratified injection in the EU and FSI = fuel straight injection in the US.

If our engines run ultra lean and thus reduces the issue of fuel dilution, NOX emissions go through the roof. It's also why on the new D5 A8 there is now a gpf (gasoline particulate filter). I don't know about the Q8. It's to help achieve Euro 6 emission standard