Several weeks ago I switched from Sunoco 93 to Gulf 93 and I saw my KR go from 4.5 to 2 and I was pleased. Then after several consistent tanks like throwing a switch my KR jumped back up to 4.5 on the Gulf. Thinking maybe it's the winter gas so not expecting any magic difference I tried a tank of Mobil 93. This is my best yet with so far a KR of 0.8. I also have found a source for E85 about 6 miles away. So I brought a 5 gallon can home with me for future blending experiments. Frankly with the readings I'm getting right now with Mobil 93, I'm not going to rush into blending. For the time being I'll sit tight and keep an eye on the Knock Retard.