Ecu, has built in knock control, therefore it shouldn't knock. Ecu , when it detects knock reduced timing until knock stops, you can measure the CF with vagcom to see how much pull is being done at any point. Only way you should get kknock is if a sensor is faulty or you've had a bad remap where CF is more than 12 and no more timing is pulled and knock will happen. There is quite a bit of tolerance in the CF , so it's really hard to induce knock unless your timing is widely out. Fuel will help lower knock but there should be enough to compensate for crap fuel.