Re: What mpg are you getting when using E85?
Ethanol and methanol are solvents, where in lies some of the problem as there are gaskets through the system. They are supposed to be the chemical resistant kind but since E85 is so much EtOH it does pull more of the plastic molecules through the engine. The car was a 2011 Regal Turbo. After many device trips over the 2.5 years running EtOH and calls to GM headquarters, Buick said better to run high Octane 93, and avoid the E85 all together. Its not that much less expensive here either, though sometimes it can be, as it all depends on the station. Mobil is the one that carries E85 most often, but now some Sunoco are carrying it as well. I figured with the amount of heavy duty industrial type solvents needed there was no benefit from the E85. I did run it for much longer than 1 or 2 tanks, as I had done that multiple times on my older GMC envoy. The chromed exhaust tips on the Regal were dark black after only 2 years using the E85. It may have been the fuel portion of the blend or it may have pulled a little oil into the combustion, but I never lost any measurable oil between oil changes, so I can't really think it was oil putting out the dirtier exhaust. There was no noticeable color change in the exhaust, just the serious gunk on the exhaust tips. Never had seen that before on any other exhaust other than diesels. I have used alcohol stoves for camping and straight methanol works very nicely without to much blackening of the pans, but that is a very short amount of exposure when comparing what an internal combustion engine uses.