Ok so some education for the E85 masses. E10 was developed for several reasons to meet EPA mandate for motor fuels having an oxygenate, a left over rule from carburetor equipped cars days. BUT hijacked by supposed clean air/renewable fuels crowd. And they used "evidence " from other EPA reports to " support" pushing it.
THEN the money lobbyists got ahold of it, started spinning about money for farmers, which is true, then they added that no human based starch/sugar produced foods can be used unless condemned as inedible,ie rotten fruit, bad alcoholic beverages, etc. Motorfuel ethanol is solely based from residuals from food production, cattle based feed stocks.
Now the beginning rule was E85 max ethanol content per denaturing rules from prohibition days. Even though fuel based ethanol can be drank it's contaminated as there is no control over distillery construction ie they can solder materials together use thinks other than food grade tools.
So now beginning standard was max E85 out of distillery, appropriate E83 on transport(remember ethanol absorbs water, if you put ever clear out in glass it absorbs water THEN evaporates more than just evaporation.
Ok so E85 at pump USED to have to maintain E70 testing level or tank had to be adjusted to GET that output ethanol content.
Ethanol is a great fuel up to a point with both good and bad points. Ford/Holley developed a dual fuel carb back when ol Henry started building cars as in certain rural areas ethanol WAS used as fuel , distilled with drinking liquor at same time. Pull lever on carb, run gas, move back run gas. Generally in the 55 to 65% it ran good in 5 or 6 to 1 compression T engines, and many NEVER saw gasoline after leaving factory!
Now bit of gasoline info, it was called "white gas" because of how it was emitted from oil cracking column when kerosene was produced(and in much finer grade than we even get now too!) In certain areas the column collected this "white gas" in liquid form. Ever see/use Coleman camp fuel, or charcoal lighter fluid (before it started being more mineral spirits like today) as Henry Ford had developed. It was poured in drains and ditches. Said to be catalyst for great Chicago fire also but not confirmed.
So first time E10 became fully ensconced, September 05, same week as Katrina.
E85 was an offshoot of gasohol and was INTENDED to move basin area cities to a less pollution causing fuel,,,,but put in place wrong as was gasohol.
So move forward 10 or so years from Katrina, the government TEMPORARY subsidy to build production/infrastructure to handle E85 was to end, marketing never pushed E85 as it should.
So it has limited availability in certain areas as the population never embraced it fully even when buying flex fuel cars, and car manufacturers never fully equipped fleets to handle it as it does require bit more cost to add it to lines. Now we have Corvette/Camaro/performance crowd starting to convert. Heck Street Speed 717 is supposedly talking E85 in his Vette��.
Now as of the decade horizon on subsidy accross the Ethanol fuel spectrum the pump standard was dropped to E51.
Now on to Ethanol compatibility, if we have to repair fuel lines switching to plastic or Ni-Copp lines or even stainless fixes majority of issues, all relavent orings/seals have been in use since flex fuel became mainstream. Gas tanks now are mostly plastic so only issue would be ethanol level sensor, bigger injectors, proper volume pumps and software. If your cars computer was used in flex fuel cars, your programmer MIGHT be able to crossbreed the fuel scaling bins into certain pcms/tunes. It's simply modifier to fuel volume and timing curve. Kind of like MAF over SPEED DENSITY tables. SD uses air temp, MAP, rpm, engine temp, to compute air/fuel ratio, where a MAF equipped car uses those tables to FINE TUNE the A/F ratio.
I know certain Monte Carlo got flex sensor,which is basically a temp sensor, ethanol sensor and out puts a scaled reading the pcm uses in adding fuel.
Certain cars scale A/F ratio based on ethanol content, some scale fuel addition IE using sensor reading to simply add percentage higher due to engines required needs based on input, the latter also moves projected O2 scaling.
It's using one of several methods to make computer adjust for ethanol content.
All engines basic function is add X fuel for X air and adjust timing per instructions, at idle/startup your going to get static advance. After it starts and stabilizes it starts constantly adjusting timing based on load/speed/knock signal return.
Some cars the module adjust retard with ecm help some don't.
Some of older flex cars don't appreciate E51 spec, EPA is debating this foolish change.
I wish all cars had been sold as flex fuel rated, just jump in. But first badged cars manufacturer gets a credit for producing