This is how it went down tonight.
For those interested here is some of the more technical info of what I did.
Because of the different stoich mixture for e85 I had to change my global fuel settings and to figure out exactly what to change it to I ran a few simple calculations.
First up was I needed to guesstimate exactly what percentage of ethanol was in my tank from the amount of e85 I put in and how much 91 was still in there. I filled with e85 and it was 12.717 gallons meaning that I had roughly 3.183 gallons of 91 left.
Gasoline has a stoich ratio of 14.7:1 while e85 has a stoich ratio of 9.8526:1 If you divide 9.8526/14.7 you get a gas ratio of 0.67. The gas ratio of regular gasoline is 1.
Breaking down what is in my tank into percentages gives 80% e85 and 20% gasoline and taking each percentage and multiplying it by the gas ratio for that portion gives me the injector correction factor.
0.80 * 0.67 + 0.20 * 1 = 0.736
Then I multiplied this correction factor by the size of my injectors which are 720s.
720 * 0.736 = 529.92
And then using the standard equation for calculating global fuel setting
450 / 529.92 - 1 = -0.151
This seems very complicated but there is a excel spreadsheet that does this automatically available on the ECMlink wiki site.
As for how it runs I didn't have any time to dial in the tune yet but my injector duty cycles went from about 73% to 97% and I am running a B16G at 19psi so for all you guys that want to run e85 out there even if you are on a 16G you need bigger than 720s to do it right.
I did a pull on the way to the gas station with 91 still and I got about 3* of timing pulled from knock and with changing only the global and putting in e85 I was beating on it with no knock. I need to find some time to crank up the timing and see what I can get out if it.