I filled the tank of the 97 GT with E85 today. I had about 1/4 tank of 87 octane left and I topped it off with E85. At the same time, I turned the knob on my tweecer to a tune designed for about 50% ethanol (3/4 tank of winter blend E85 which is actually around E70). All I did was change the injector slopes and richen up the WOT fuel target a bit. The tweecer knob has 4 settings, so switching between blends will be no problem at all.
So far, so good. I will report back on gas mileage changes later on, but before the switch, I was averaging 21mpg (20mpg if I have lots of fun, 22mpg if I careful). To me, it feels like the engine runs a little smoother, especially at WOT. I had a pretty aggressive tune for 87 octane though, so I may have been getting a little inaudible detonation on the 87 octane.
In the past, I ran mixtures of up to 30% ethanol on the stock tune. In fact, about 3 years ago, I ran the whole summer on E30 and cleared up a knock problem I had (probably a dirty fuel injector that was cleaned by the E30). On that mixture, the long term fuel trims changed and I never got a CEL. The gas mileage didn't notibibly change and the WOT AF ratios were exactly the same running E30 and 87 octane, so the computer compensated perfectly. Now, I can run more ethanol using the tuner.
As for why I want to run E85: first, it is cheaper... we'll see if the fuel mileage decreases too much to break even or not. Second, for fun. I enjoy doing something different and learning along the way. Third, less dependence on oil. Yes, making ethanol from corn is just plain stupid, but with enough intrest, maybe we will use other existing methods (like sugar beets or sugar cane) and develop new methods which are even more efficient.
So far, so good. I will report back on gas mileage changes later on, but before the switch, I was averaging 21mpg (20mpg if I have lots of fun, 22mpg if I careful). To me, it feels like the engine runs a little smoother, especially at WOT. I had a pretty aggressive tune for 87 octane though, so I may have been getting a little inaudible detonation on the 87 octane.
In the past, I ran mixtures of up to 30% ethanol on the stock tune. In fact, about 3 years ago, I ran the whole summer on E30 and cleared up a knock problem I had (probably a dirty fuel injector that was cleaned by the E30). On that mixture, the long term fuel trims changed and I never got a CEL. The gas mileage didn't notibibly change and the WOT AF ratios were exactly the same running E30 and 87 octane, so the computer compensated perfectly. Now, I can run more ethanol using the tuner.
As for why I want to run E85: first, it is cheaper... we'll see if the fuel mileage decreases too much to break even or not. Second, for fun. I enjoy doing something different and learning along the way. Third, less dependence on oil. Yes, making ethanol from corn is just plain stupid, but with enough intrest, maybe we will use other existing methods (like sugar beets or sugar cane) and develop new methods which are even more efficient.