I feel like I can actually contribute to this thread in a meaningful manner, so I'll give it a shot.
There's a couple things to know about E85 as a fuel and as it relates to MPG:
Everyone already knows that increasing the thermal and flow efficiency of the engine will improve MPG; what most people don't realize is that Ethanol is a superior fuel for improving efficiency.
What I mean is this:
The two easiest ways to improve efficiency of a vehicle's engine is to improve airflow into and out of the cylinders; headwork, cams, larger intake and exhaust piping, etc. The other is to increase the compression ratio, leveraging more of the heat produced from burning the fuel into kinetic energy.
Ethanol has a much higher octane rating than pump gas, and will allow an engine to leverage a higher static and dynamic compression ratio, thus improving economy.
I'm currently in the process of rebuilding the engine in my car specifically to run on E85; this includes but isn't limited to cams, headwork and, of course, the highest compression ratio I can stuff in there via custom pistons and rods. With this engine, I expect to be able to easily exceed stated MPG of the stock car on full E85 fuel, while also making somewhere north of 400 horsepower to the wheels.
Questions? Comments? Let me know. I've done a TON of research on this as it pertains to direct injection and my specific car; might be helpful.
Side note:
Quote:
Originally Posted by roosterk0031
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Are you affiliated with SP63 or just using their site to pull the study from because it's convenient? Not slinging mud, just curious.
Also, keep in mind any "flex fuel" vehicle isn't optimized for either high blend ethanol fuels or straight pump gas, but are a compromise between the two.
As an example: on my almost entirely stock engine car (before I blew it up), I was getting better than stock MPG on a 50/50 mix of E85 and pump gas (about E45 or so), but that had everything to do with the tune and driving style. It was even better than most people were getting with non stock tunes/mods and straight pump gas, to the point that quite a few were astounded since they thought they got really good mileage themselves.