Originally Posted By: Vikas
E15 means 15% Ethanol and 85% gas.
What does E85 mean?
Well, the first thing you must keep in mind is that the numbers refer to maximum content levels. That is, E10 can contain a maximum of 10% ethanol. Likewise, E15 can contain 15% and E85 can contain 85% ethanol.
As was pointed out in another post, in colder weather, E85 will typically contain only 70% ethanol. This is to improve the cold starting performance of the flex-fuel engine, as ethanol has poor low-temperature properties. The E85 markings are retained year 'round simply to prevent possible confusion among the general public.