spyder_xlch wrote:I'm puzzled about the dual fuel engines. Like Tom said E85 can handle more compression. You'd probably would get better mileage if the compression ratio was higher. The engine has to run richer on E85. How does the computer compensate for this? Do you flip a switch when you run E85 to make it run richer? And what about the compression ratio? You can't change that with a flip of the switch. Or does varriable valve timing help bump the compression up? I don't think you could make the engine run at it's best in a dual fuel situation. I'd think you'd have to pick what fuel you want to run and build accordingly (like Nic is doing).
Chevy and Ford use a fuel sensor, Dodge looks at the fuel map. I had the pleasant experience of diagnosing a car that had been filled with E85 and was not designed for it. Long story short, the adaptive memory went to +33%, and put the light on for "adaptive numerator at limit". Had it been one of our flex fuel vehicles, the pcm would simply have triggered an alternate fuel and spark strategy at the onset of +30% adaptives and carried on, business as usual. Lambada is the same, it just takes 9.5:1 fuel to reach the o2 sensor's switching point instead of 14.7 for gasoline, which is coincidentally around 33% more fuel.
