Corrosion: because the alcohol in ethanol corrodes aluminum, FFV components are made of stainless steel and E85 pumps must be modified or manufactured with stainless steel to prevent corrosion. Repeated exposure to E85 also corrodes the metal and rubber parts in older engines (pre-1988) designed primarily for gasoline.
Cold starts: because E85 has a higher freezing temperature than gasoline, there may be cold start problems in severe cold weather. For that reason, ethanol content is lowered to a minimum of 70 percent ethanol in freezing weather conditions.
Limited to light vehicles: due to its physical properties, ethanol is generally limited to gasoline blends for passenger vehicles and light trucks, while heavy-duty vehicles are diesel-fueled. Current researchers are experimenting with E-diesel, a blend of fuel ethanol and petroleum diesel.
Environmental Concerns
Growing corn requires a significant amount of water, fertilizer and pesticides, which can have a negative impact on the environment. On average, farmers use about 134 pounds of nitrogen fertilizer per acre of corn each year. Some potential cellulosic energy crops can be drought-tolerant and use less water than corn. Ethanol is biodegradable, so accidental spills pose few risks to the environment.
Food Versus Fuel
There is a growing "food versus fuel" debate as the cost for corn spirals upward due to high demand. High corn prices are good for farmers, but bad for livestock producers and consumers, because so many products are made from corn. Texas has a large livestock industry, and high feed prices affect it. This debate has generated increased interest in cellulosic ethanol.
Link to where the above came from and I could get hundreds more , for the engineer in here , you should know all this already and not calling the guy on so I though I would post some proof
http://www.seco.cpa.state.tx.us/re_ethanol.htm
Now to more e85 facts
Higher RON in the fuel blend would enable greater thermal efficiency in future engines through higher compression ratio (CR) and/or more aggressive turbocharging and downsizing, and in current engines on the road today through more aggressive spark timing under some driving conditions.
Using a linear molar octane blending model they had developed earlier to quantify RON potential from ethanol and blendstock, the team estimated that an increase of 4-7 points in RON are possible by blending in an additional 10–20%v ethanol above the 10% already present. Keeping the blendstock RON at 88 (which provides E10 with ∼92.5 RON), they estimated RON would be increased to 94.3 for E15 to as much as 98.6 for E30. Further RON increases may be achievable assuming changes to the blendstock RON and/or hydrocarbon composition, they suggested.
An increase in blendstock RON from 88 to 92 would increase the RON of E10 from 92.5 to 95.6, and would provide higher RON with additional ethanol content (e.g., RON of 97.1 for E15 to 100.6 for E30).
Under scenarios considered in the paper, the team estimated CR increases to be on the order of 1–3 CR-units for port fuel injection engines as well as for direct injection engines in which the greater evaporative cooling of ethanol can be fully utilized
From :
http://www.greencarcongress.com/2012/04/jea-20120406.html
No manufacture of "E" fuels will tell what octane there blending with so you can figure what fuel your using , now some states are running 85 octane fuels regularly (
http://www.ethanolproducer.com/articles/8858/octane-whats-in-your-fuel), and why they are not required to post octanes on the pumps for E85 , what makes people think there not using 78 octane to make e85 , or 72 , the lower the octane blended the cheaper to make octane fuel
The key word is the "blendstock" they wont even call it fuel any more there mixing and even stat that the "blendstock" / fuel octanes are/could be lower or higher which changes the outcome of the loosely use octane of the final product
It amazes me that people using it or educated people claiming to know a lot about it still feel its the higher octane that adds the benefits why its the greater evaporative cooling of ethanol as by cooling the charge lowers the chance of knock to the point of low quality "blendstock" is used and you get a lower octane fuel substitute
vance I 100% agree with you on your thoughts , most of your statments are spot on and I though I would post facts to back up your post and where they can read them
I have tuned many many "E" cars over the years , I have seen first hand cars go out with 100% 0 knock and come back with another tank and have 3-5 deg of knock using the knock sensors , it is an unregulated fuel and until its regulated they will use junk fuel to make it and that's not even taking into account the amount of water "E" fuels get into them , how the "E" fuel have to be belended just before shipping as the octane drops over time fast and I could go one and on but you will still get the guys that think its a "higher octane race fuel" LOL
The above link , which is a joke read and means nothing for "E85" testing talks about E100 and 91-93 octane fuels which was also paid for my Ford and AVL which are paid by the oil companys , give me E100 at the pumps and I will run it ALL DAY LONG , E100 is a regulated fuel and controlled by big brother just like 93 octane is , E85 is unregulated do the math and see where you would be if the "blendstock" was 85 or 78 or 72 , yep now your getting it
Tom