2002 Audi TT Question Gas

Any forced induction gasoline motor should be run on premium fuel only. Additives might work but why not just use the recommended fuel, it would probably be cheaper. The knock recognition can only do so much and there is a region that the engine works in that even when using premium fuel will require the knock recognition software to retard ignition timing such as high load under boost with a large throttle setting, if you exceed the region where the knock recognition software is able to be effective by using incorrect fuel, then all the additives in the world wont save that engine, it will be damaged by the detonation of the fuel instead of burning it as it was meant to be. Hope this is what you needed. ♥