Does summer fuel give better or worse fuel economy?

[cheapybob]

With my hot air intake, I won't get better fuel economy because its warmer out like most people would, because my air wasn't cold in the winter. I guess my fuel was, though, but not sure how much effect that might have.

I'm in the Chicago metro area, so we have the low pollution fuel, whatever that is.

Has anyone tested summer blend vs winter blend under the same warm weather conditions?

How much difference was there and which was better? I'm just wondering if I've lost a little MPG due to the change to summer fuel. It seems like my numbers are maybe .5 to 1 mpg lower than they were on the previos tank which was winter fuel.

[n0rt0npr0]

I am about to start testing Winter Blend VS summer blend fuel.

My results should be comparable to where you live. Once I get the phone call from Shell, MArathon or Admiral that we've been delivered summer blend fuel I will begin testing. But usually it takes until the last week of May to begin selling summer blend here in Detroit.

[rh77]

I'm getting slightly higher mileage, probably due to the higher humidity of the warmer months (denser air for the mix). I believe we switch to standard-blend (no crapoline) here in the Spring, which also has to help.

RH77

[diamondlarry]

The crapoline seemed to go away around the first of April.