Originally Posted by 94rangeron35s
I call bs on that everything metal because I know that no auto manufacture is going to put stainless pistons or a stainless block in everything that can run e85
Well, you're giving it good thought, but there's something going on in the engine that helps it fight the downside of ethanol: Combustion.
OEM fuel systems were upgraded to ethanol-proof o-rings / plastics (for the solvent nature) and stainless in the metal parts because ethanol is like brake fluid - hydroscopic. Biggest difference why tour brake system doesn't need to be stainless is because it's not normally open to the air to pull moisture out of it. A fuel system, however, is open to the atmosphere (through a vented carbon canister and every time you take the gas cap off) and the in-ground fuel tanks at the station are as well.
E100 will tend to pull the humidity around the atmosphere until it reaches "E95" with 5% (by volume) water. This is also why you never see any alcohol for sale more than 190 proof - it's too damn hard to keep the water outta the mix, so the don't. It gets distilled to 100% or so and let it reach an equilibrium with the water volume.
So...the water that ethanol attracts and holds in suspension can be pretty tough on fuel system parts that are not rust-resistant. Once in the combustion chamber, however, there's not enough time for the water to harm anything because it gets vaporized during combustion and leaves the engine as steam.