Now that I have a Gen2 Vibe, and gas prices are at or above $6 in california again, I want to see what the results are for a mix. Having learned a bit from the Gen1 trial, this will be more simple.
I am starting with a near 50/50 mix. While around 1/8 of a tank I added 5.9x gallons of 87 at 5.89 a gallon and 5.0x gallons of E85 at 3.69 a gallon. This rough math puts me at $4.90 a gallon.
After using 1/4 tank, my fuel trim add is +10 when cold and +15 driving. I have seen as high as +18 in some spots. As mentioned in the Gen1 thread, I really only do city driving, maybe 10-15% max on the highway.
Even if I only save $5 per tank, it is still a win as I fill up often. I would like to be able to get 300 per tank on the mix. The gen1 was getting 200-225 per tank on full e85.