Thinking about converting to E85. Excuse me for a minute while I kinda think out loud here.
E85 is 104-105 octane and therefore it´s more knock-resistent and can tolerate more boost or a higher CR. It cools the intake charge better and therefore makes it more knock-resistent and it also makes the engine run cooler and to some degree, even safer. In most cases it's at least 5% more effícient than gasoline at the same lambda value (up to 25% more efficient on some cars optimized soley for E85). Since E85 has very good cleaning properties as well as leaving behind a by-product of water, it is cleaning the fuel system and it will keep the injectors nice and clean. The combustion chambers, valves, ports and the exhaust will also be cleaner, almost like the car had water injection. In most cases it will cost less $/mile to run on E85.
The down side of E85 is moisture and is a little harder to start in cold weather. It also requires about 42% more fuel to reach stoichiometric, or ideal air fuel ratio.
The good thing is the O2 sensor doesn't care what fuel its running. It doesn't even know. It will make adjustments to run a 14.7:1 AFR, or Lambda 1. E85 is 9.765 stoich, or Lambda 1. So your O2 just looks for Lambda, not AFR. So my wideband would read 9.76 at stoichiometric.
I started thinking about this after talking to a guy at work that is thinking about buying a '66 389 engine for his '65 GTO. It was an original 389 tripower with a 4 speed and currently has a 400 4 barrel 4 speed. We were discussing the 389 that has 670 heads and isn't converted for unleaded fuel. The 670 heads combined with 10.5:1 CR is not pump gas friendly even if he changed the seats in the heads for unleaded fuel. He was thinking just adding additives to the fuel instead of doing head work and running 100 octane. I told him he could change valve seats and also do guides and valves with new seals and run E85 for the 104 octane which got me thinking about doing this to my engine.
For right now I'm going to stay on course and run what I have to get used to tuning and get the trans and rear diff changed before I go to E85. But I will start collecting parts for it. I don't know for sure that my fuel lines will be good for E85 but I can change them and also put in a dual or bigger fuel pump. Should be able to make changes to fuel and spark mapping and get better safer power with boost. Anyone do this? Besides you guys with flex fuel. You guys have a sensor in fuel line which switches programs in your computer. I'll have a saved tune for gasoline which would allow me to go back and forth between E85 and gas with just a simple load of the tune.
