Originally Posted By: SecondMonkey
In Oregon now, we are allowed nothing but E10 fuel year round.
Knowing that alcohol adds octane to fuel, when they're mixing up a batch of "87" E10, do they actually start with a lower octane base fuel?
After I did a little searching, it looks like the answer to your question may be "yes"
and "no", with no way to tell which areas and station are selling the enhanced octane fuel.
Ethanol Q&A
Quote:
Q:Is E10 octane 89 sometimes the "plus" at the pump?
A:The octane rating of E10 is determined by what fuel the ethanol was blended with at the terminal. Adding 10% ethanol to gasoline adds 2.5 to 3 octane points. If the stock gasoline was 87 octane, the E10 blend would be either 89 or 90 octane.
Some markets use sub-octane gasoline that is 84, and when blended with ethanol, becomes standard 87 octane fuel. Most states require E10 to be labeled, but some do not. If you do not see ethanol labeled at the pump, ask the retailer. If they don’t carry it, tell them you would like to have that option.