
Originally Posted by
Fivefingerdeathpunch
Unless you can tune for it, you won't want to do that.
E85 requires at a minimum of 30% more fuel flow compared to regular unleaded gasoline.
Even though E85 if it's actually 85% alcohol is roughly 105 octane there is a draw back (most winter blends are E50 or E60 right now). It requires larger fuel injectors for more fuel and should always be tuned for. Also you get roughly 30% less fuel mileage.
So even with a 50/50 mixture it's likely to be around E30 or E40 in the tank. Sure it's higher octane than regular 91 by a little bit but it's still something I wouldn't do unless you had a tuner.