I just started blending E85 with regular 87 E10 over the last couple tanks in my 96 non-flex-fuel car. The first tank was a blend of around 20% ethanol. MPG was only 1 MPG lower than the previous tank on reg 87, and this could have been due to other factors.
The first thing I noticed was the overall drop in mid-range horsepower, it takes more pedal now to get the same acceleration power as before on reg 87. This is great for my car because I only normally use about 35% throttle max to achieve a 75% engine load while accelerating (max load before knock sensor starts retarding timing on 87). I found that I can now run up to about 25" Hg man. press. without knock at 2500 RPM and 23" at 1500 RPM. This is a slight increase from the 24" at 2500 and 22" at 1500 running reg 87, meaning that I can use more throttle now resulting in less pumping losses, although 22" seems to be the sweet spot for acceleration.
The funny thing is that low-end torque seems to be quite improved by the ethanol blend. This might just be due to warmer weather, but it feels like I use much less pedal at cruise to maintain speed.
Scangauge reports similar or higher real-time MPG than when running reg 87 at cruise. I'm not sure if this is simply due to the way that SG calculates MPG or not, though I did have to bump up the fuel correction from about +7% to +9% for the first fillup. I have also been watching the fuel trim. Before, it ran at about -6 to -8 at cruise. With E20 it is about -3 to -4, and with E30 it runs between 0 and +6 for city driving so far. This indicates that I should be able to further increase the percentage of ethanol without compromising fuel delivery.
The only thing I really worry about is the rumored corrosiveness that ethanol supposedly has on fuel system components. I watched
this video in which a couple of mechanics tore apart a non-flex-fuel vehicle that had been run on E85 and showed no signs of degradation. However this video is sponsored by a pro-ethanol organization, so I'm not sure how much credibility it actually deserves. Although I haven't yet seen any videos in which they have torn apart engines and actually FOUND premature damage from ethanol fuel.
I will be making the 180 mile trip across the state again today, and I should have some results of how the E30 performs.