I have notice alot of stations in Wexford county stating "no ethonal" I really wonder if it is true. I have not seen the detonation problems this year like last. Also I bleive if you are jetted factory jetting, which is rich anyway, this will help eliminate the possibility of detonation. It won't stop the corrosion issues of ethonal though. I have been using Sta Bil for ethonal marine formula every time we are finished for the weekend. 6 oz per tank. Al