In our region gas retailers must sell at least 7% ethanol content of all fuel they sell by volume. We can get 91 with zero ethanol, 89 octane with 5 percent ethanol and 87 octane with 10 percent ethanol. That's how they arrive at their 7 percent content, give or take.
Ethanol is a good anti-knock additive in fuel for octane purposes which is fine, but it gives less fuel economy which I don't like. I'd rather have no ethanol in order to get the best fuel economy but I'd have to go up to 91 to get that.
I'm sticking with 89 octane right now, I think the turbo will work well with this fuel , the extra cost doesn't bother me as it will be offset with some fuel economy benefits. If I can run this octane consistently the ecu will probably run more timing advance over the longer term rather than retarding to compensate for lower octane fuel. Just my opinion here.
I get just over 45 mpg's in straight highway driving conditions at 70-72 mph cruising speeds. Not too bad given the cooler temps and the onset of winter gas in our area.
2016 Coupe Touring - Blue
2002 Honda S2000 - Silver with Blue and Black custom interior. Garage Queen.
2015 Jeep daily driver workhorse.
Last edited by JS2000; 11-02-2016 at 10:49 PM.