Winter vs summer fuel mpg
 

https://www.gasbuddy.com/go/summer-b...blend-gasoline


Gas buddy released this talking about the price drop in gas after switching. What they didn’t mention was that summer blends also have more energy and typically get higher fuel economy numbers

What I’m curious about is how much of a hit are we talking with the summer to winter mpg blends? Obviously ambient temperature has a big impact, but what about when comparing at the same ambient temperature?

If you car gets 50mpg at 60 degrees with summer blends, what will the Mpg at 60 degrees with the winter blend be?

Also will aerodynamics play a bigger roll in cold weather since the air is more dense? What eco mods can help offset the winter blend transition?

It says that winter blends heat up faster too, which I don’t know if that means your engine can get to a warmer temperature or not faster? If that’s true, that’s a benefit for hybrids

https://ecomodder.com/forum/showthre...nce-39987.html

I lost 7%, no changes to the car, oil cooler taped off and radiator partially taped off, and I noticed the bad mpg on a balmy 60F day. The difference is supposed to be around 2% before accounting for increased drag. Winter fuel runs better in a cold engine since it has higher vapor pressure, but the ECU doesn't care what fuel you put in when it runs rich on a cold start so there aren't really fuel savings.

I still can't explain the huge drop. I was using Costco fuel while the previous tank was 76, and Raley's fuel from Nevada seemed to be even worse. I still get Costco fuel when it's convenient because it's still a great deal even if something is "wrong" with it.

So Costco summer blend to Costco gas winter blend should only be 2 percent drop in theory? Hopefully that’s true. I’ve never really done any tests since winter time here in Oregon is usually full of wet roads, chillier temps, and I put on winter tires for ski resorts, which surprisingly highway mpg is barely changed between winter and summer tires. City driving is night and day though

I've never measured a drop in economy due to fuel alone. It follows temperature pretty closely.

I usually do notice the drop in mpg from winter fuel but I have never seen it drop this much, so I assume something else must have happened. I think the Raley's winter fuel might have been worse than the Costco fuel. I burned most of the Costco winter fill away driving into a 20mph headwind.

I can believe 4% variance in fuel. You can get that from more light hydrocarbons like butane/pentane/hexane and ethanol.

I have no way of properly measuring but I thought the mpg was extra bad when I was driving in freezing temps. Whether that's because the transmission fluid is more viscous, or if the engine coolant temp is low (it failed to get over 190F, so reduced timing is a possibility), I don't know. I'll probably add one more strip of tape to the grill in the winter to help it stay warm.

Yeah in winter I was thinking of closing off this one little area that still gets air flow permanently bellow the active grill shutters and was going to also insulate the hood

My real world day to day experience with the switching to 10% ethanol fuel around October, is I lost about 25 to 30 miles per tank in range. In the summer, I could go about 310 - 315 miles commuting before the fuel light came on, then in winter the fuel light comes on around 280 - 288 miles or so.
This is in my 2006 Crown Vic PI, with a 19.1 gallon tank (fuel light goes on with 16.1 gallons used), which was last year's daily driver. My Crown Vic isn't stock, I have a bunch of performance mods, run a performance tune, and use premium fuel.

So adding 10% ethanol and colder temps = more than 10% loss in gas mileage. Some of this loss is also driving in the rain, which is about 80% of the time around here after October.

That could definitely explain the range drop i get in the winter. When I drive from Portland to Boise in the summer, I can get there on a full tank of gas with a little left over. In winter, I usually have to stop near the stateline to squeeze in 5-10 extra dollars of gas at the pump to help get me to boise so I can fill up at Costco lol

Also explains why I burn clear Premium in the Superbeetle.

Raleys is a Cali based company, so default uses apcd fuel which is different from everywhere else except SOCAL. Bunches of anti-smog additives not noted for performance or efficiency, juries out on whether they improve air quality. Costco in many locales (except Reno/Washoe county) gets fuel trucked in from non apcd origins. Costco fuel from Carson City is known to be a better fuel and significantly cheaper due to lack of excessive road taxes.