Slim -- to answer your question yes the E10 stands for 10% ethanol mixed with 90% gasoline. E33 would be 33% ethanol mixed with 67% gasoline. E85 by law can have anywhere from 70% to 85% ethanol depending on the season.
Dean -- some of your information is incorrect/outdated based on real world tests on E85 conversions and cars running high blends in unconverted cars.
All modern cars can run on at least E15 with no modification, most will run on 33% E85 (ie about 25% ethanol) In the 1970's Brazil did tests with cars of that era and ALL of them could run on 22% ethanol without modification. That is why they standardized on that level of ethanol for many years.
On carburetor cars you are correct, you need to adjust fuel flow slightly for low blends of ethanol as they will lean out slightly, but the lean out is not harmful due to ethanol's cooler burn temperatures and higher latent heat of evaporation. In Modern cars with electronic fuel injection it is not a problem as the ECU makes these corrections automatically.
My Subaru WRX was typical of modern cars. The stock ECU has plus or minus 15% mixture control built into the ECU. As a result you could run a blend of up to 33% E85 in a completely stock car with no problems of any kind! I did it for over a year. At 33% blend the ecu would throw a check engine light telling you it had used up all of its fuel trim authority but the car ran fine on up to 50% blend of E85 ( I never bothered going higher because at that blend you began to see hard cold starts in the winter and fall).
In later conversions I set the injector scaling so it was at 0 fuel trim at a 50/50 mix of E85 and gasoline and the car was essentially a FFV. I could put any blend of both fuels in the tank and it would work acceptably. I later went to an adjustable fuel pressure regulator and with a 10 second tweak to the fuel pressure I could eliminate the slight enrichment on straight gasoline and the slight lean out on E85 at wide open throttle.
Some modern cars are actually FFV's in disguise as they will adapt to over 90% E85 blends if you work up to those high blends over a few tankfuls. (some Chrysler products are known to do this)
The cars are warranteed to run on up to 5% methanol and 10% ethanol blend but in fact will handle far higher ethanol blends. Some of them get best power and fuel mileage on higher blends of ethanol. The ASTM standard for E85 also strickly limits water content (less than 1% and blenders typically will not buy it at over 0.6%) very low acid content, sulfur content and methanol content all to limit corrosion. Commercial E85 also has a corrosion inhibitor added so it is no where near as corrosive as some old timers remember the first gasahol blends back in the 1970's.
E85 actually runs just fine on exactly the same ignition advance as the gasoline fuel curve uses. My first conversion I only changed the size of the fuel injectors NO other changes. I ran the car for over a year that way, got up to 92% of my gasoline fuel economy per gallon, and better performance, and passed Colorado's IM240 dyno emissions tests with flying colors (my emissions were actually lower than on gasoline). It takes a bit longer for the cats to light off due to the 200 deg F cooler exhaust gas temp but that is trivial. The adaptive tuning used in modern electronic engine management systems make all the necessary fuel mixture adjustments at closed loop fueling. They do go slightly lean at wide open throttle but this is not an issue for stock engines and daily drivers. The cool burning characteristics and high octane of E85 protect the engine. I have (unintentionally) gone wide open throttle at 15psi boost at stoiceometric fuel air mixtures on E85 with no problems in the WRX. I know folks who have done the same thing at near 30 psi boost (briefly) without hurting the engine in DSM's.
It is desirable to fatten up the wide open fuel mixture tables for best performance, but for daily drivers it is not a serious issue as you do not spend enough time on the the highway at wide open throttle for it to be an problem. In fact most cars running high ethanol fuel blends have difficulty getting warm enough to run right.
No physical modifications are necessary to the engine to run high E85 blends or even straight E85 in modern engines. They will run better and get closer to gasoline fuel economy if you bump the compression ratio but it not necessary. The stock engines work just fine on it. In fact on tear down, they are much cleaner inside and show less wear than on gasoline.
Acid neutralizing oil is not required, the last hold out was Chrysler and they dropped that requirement years ago when they realized it was not an oil issue. The real problem is that E85 burns cooler and allows water to build up in the oil due to low operating temperatures. If you keep the oil up to normal operating temperatures so it cooks condensation out just like it does on gasoline no problems of any kind. I ran 15,000 mile oil changes on synthetic oil with no problems on my Subaru.
The cold start does need to be addressed on cars running very high E85 blends with no conversion or full conversions running E85.
On my subaru the simple solution to cold starts was to add 2 gallons of gasoline to a tank of E85 when temperatures dipped below zero. Car started just fine after 12+ hour cold soak at -15 deg F temps. Once you get the ECU fuel curve dialed in they will start cold as reliably as on gasoline, but it is less forgiving to a weak battery as it needs good cranking speed at 8:0 compression ratio in cold weather to get good starts. At higher compression ratios it is not an issue as the compression heating during the compression stroke will get the fuel vaporized properly to light off.
Corrosion issues with E85 are blown way out of proportion, comparisons with methanol are not realistic, methanol is more than 10x as corrosive as E85 and is well known to attack light metals like magnesium. I have had interaction with literally hundreds of folks who have done full E85 engine conversions and to date we have not had a single confirmed problem with corrosion that was problematic.
We even use fuel pumps that are not rated for E85 and they survive so long that the factory asked us to send them in to be analyzed as they could not understand why they lived so long in the real world. I sent in a Walbro 255 l/hr high performance pump to the factory for them to evaluate with over 30,000 miles of use on it. The only problem they could find with the pump was slight corrosion of the plating off of the electrical contacts to the pump (it stripped the plating off due to dissimilar metal electrolytic corrosion.) Once the plating was gone, the corrosion stopped, many people are getting similar service life out of these pumps in E85 that you get on gasoline.
As far as gaskets go, yes some of the very old gaskets had problems. The old cork and rubber composition gaskets in holley carburetors really did not like ethanol. Fuel lines in european cars (my 1969 VW) were not happy with it either when we changed to ethanol fuel blends here in Denver in the late 1980's. Some old fuel pump diaphrams in mechanical fuel pumps broke down due to ethanol added, but they did the same thing with gasoline but most people forget we had to replace those old pumps even when they had only seen gasoline.
All American Market cars manufactured since 1992 have fuel systems that have ethanol added fuel compatible hoses and gaskets, since that was the time period that ethanol began to be added by law in some locations. I have driven on ethanol added gasoline since the late 1970's when they first introduced it here in the Denver area with no issues other than the fuel line in my 69 VW.
That is my personal experience over 40 years of driving on ethanol added fuels and over 70,000 miles on an E85 conversion of my WRX and using high E85 blends in both my 86, and 88 subarus with no conversion changes. We have about 100 E85 conversions here in Colorado many of them high performance turbocharged with no corrosion problems, and no engine damages due the fuel.
Larry
