I have a question on octane. I was at the local sheets the other day and I was looking at all the options they have the flex fuel (e85) they have a E 15 then the normal three fuels 87 89 91. The e15 is rated at 90 and is for use only in 2001 newer vehicles. So it has a higher ethanol level but a higher octane than regular 87. What does the 5% extra ethanol do that you cant use it in older than 2001 vehicles? It is somewhat cheaper than 87 regular gas but i have always been scared to run it. Even tho my truck is a 2001.
