Tried this just last week during refilling for full tank. Used up 200ml for 90ml for 90 liters. Have not researched correct ratio yet that is why. But knowing that it burns with gasoline and it has decarbonizer (Shell 2T), I assume that it will help clean the exhaust parts. have not really checked whether it improved the engine noise. Will check next time when I refill again.

based on my research, ratio is .8ml for every 1 liter.