Here in Oregon we get "winter" gas with 10% ethanol blended into it from November to April. Now, in my piston engined cars, this results in a drop in fuel economy. My E30 BMW 325i went from 25.5 in the summer to 21.5 in the winter, and back in the summer. My Miata did similar things, but with slightly less spread. My Honda CR-V does this as well.

Does the RX-8 exhibit this behavior?

 

of course, also, most gas in the us is now an ethanol blend at 10 to 15%

 

Most gas in the US is 10% ethanol blend all of the year. States that get winter gas, im in one of them, I think its something other than the ethanol that makes them a winter gas. I could be wrong though.

 

Doesn't seem practical.

A loss of 16% MPG with a 10% Ethenol means we actually consuming more gas than if we left it alone.

I bet alot of cars are in the same boat.

So regulation makes us consume more gas.

 

My mileage has been 11mpg in the winter and around 12mpg in the summer. I don't know if this is the gas, season (temperature) or the car just breaking in. I bought the car last Winter so I need another year under my belt. Look at some of the long term gas mileage figures. There are a few posted with dates so you can pick out the winter months and decide for your self.

The switch to a 10% alcohol fuel will only decrease mileage about 4%. Most the decrease in fuel mileage during winter could be attributed to longer warm up times when the engine is not running at peak efficiency.

 

My BMW was a wierd beast, though. Motronic 1.1 isn't without its faults.

The CRV only looses 1 mpg in the winter.

Fortunately, we still get real gasoline here in the summer, at least if you buy it from Chevron, Shell, or 76.

 

My mileage drops about 10% in the winter.