Originally Posted by Skooterbrah
Do you have a wideband in the car? I have one, but my main concern would be running lean with E85 in the tank. I know its not a full tank, but even a blend with the 625 kit MIGHT max out the injectors/pump. I'm tempted to give this a try and see exactly how she does with 3 gals of corn in the tank. Lemme know how your AFRs read.
That is a legitimate concern. I have a non-intercooled kit, so I have more headroom than you do before I max out fueling. With an E85 blend, it would be better to run a bit on the richer side as well since E85 has less energy than E10 fuel and the fueling requirements are higher. I would take it slow; add a couple gallons and see what your AFRs are. No sense in going overboard when experimenting. Keep the ratio small to start and you'll be ok. Please do a log before you add any E85 as well.
There are plenty of examples of boosted cars benefiting from running a mild E85 blend on stock tunes, especially in the hotter summer months.