http://www.injectordynamics.com/AlcoholArticle.htmlInconsistent Ethanol Content
The whole point of running E85 is to take advantage of the superior properties of ethanol, right? And E85 means 85% ethanol, 15% gasoline right?
Referring to "ASTM D5798-11 Standard Specification for Ethanol Fuel Blends for Flexible-Fuel Automotive Spark-Ignition Engines" we see that the 85 in E85 signifies a maximum ethanol content of 85% with the remainder being "unleaded gasoline, gasoline blendstocks for oxygenate blending (BOB), natural gasoline, or other hydrocarbons in the gasoline boiling range."
Clear enough. 85% Ethanol and 15% WTF-ever, right?
The 85 percent doesn't refer to pure ethanol, but to denatured fuel ethanol which already contains 2% gasoline to make it "unsuitable for beverage use under a forumla approved by a regulatory agency to prevent the imposition of beverage alcohol tax."
The real meaning of that bit of lawyer-speak horseshit is that E85 has a maximum ethanol content of 83%.
And that defines our maximum, so what about our minimum?
Are you sitting down?
The original specification set the minimum ethanol content at 75% which was lowered to 68% in June of 2010, and lowered again to 51% in June of 2011. As of February 2012, this is the current specification and E85 purchased from the pump could have an ethanol content as low as 51% and still be within spec.
So now that you know the what, you're probably interested in the why. At least I hope you are. You didn't come here with a blank stare and drool running down your face expecting to see how many people "liked" E85 did you?