It is funny how people get crazy about ratios. When you say 90 or 100:1 it always creates all sorts of comments. They fail to understand about concentrate. When Amsoil mixes 7.4 oz for 5 gallons and and most others are twice that for the same gallonage. It is wierd to put so little in and have it lube and protect the same and the others. This is always a fun debate. Try it all! and judge for yourself. That will require a lot of seat time, but, that is OK too.