Mileage Observations, LOVES hot air.

[jwalz1]

So I still have only 6000 miles on the odometer and I have a love/hate relationship with the gas mileage in this car.

First, it is a 2010 V6 AWD model that is primarily used as a winter vehicle and rain beater in the summer because I drive a summer car when the weather is nice.

In Minnesota, we do not have winter blend fuel, we have 10% ethanol mandate year round.

When I first got the car we were having a warm fall and my very first tank was 23.5 mpg. Pretty pleased given it was not broken in. Shortly after the first tank it got cold here and stayed that way for a long time. The colder it was the worse the milage became. I struggled to get 19 per tank in the really cold stuff, averaged about 20mpg most of the time.

I realize that the major difference in cold weather is "time to full operating temp" and that modern cars run very rich as a protective measure until they are at full operating temp. The colder it is, the longer the run rich. This is only part of the story. I drove over the Christmas holiday two stretches of 300 hundred miles pretty much at a non-stop highway clip each way in about 20 degrees. Even though 99 percent of the trip was at a 65-69 mph cruise at full operating temp, the car never pulled above 21.5 per tank.

Flash forward to this week, I filled up, started a new tank, drove 100 miles on my normal commute (a twelve miles run with a mile of city on either end of a ten mile 65 mph highway cruise). For that hundred miles, it has been in the nineties here and the mpg on the tank read 26.4 mpg. Now today it is much cooler, about 59, and I took a nice long freeway jaunt and it has dropped steadily to 25.2 in 30 miles. Relatively flat terrain, no real wind, steady cruise. The only difference is the air temp. My mileage indicator usually is a bit optimistic, but I find it is pretty close when I fill up and do the calculation manually.

When my driving patterns are the same, a steady cruise in warmer temps always yields significantly better mileage. In my short time with the car, the difference between very cold and very hot get me over 30% difference in mileage. Whatever the computer does, it compensates for cool temps with a much richer mixture, and almost to an exaggerated fashion.

I am very pleased with its warm weather mileage and actually fairly impressed given the size of the vehicle. Unfortunately for me, I bought it for the winter and was hoping the difference would not be so drastic.

I also don't have any real proof, but I seem to notice the actual current mileage readout to show better efficiency at around 72 than 65. I don't know why this would be, given increased drag at higher speed, but perhaps a throttle more open and gearing keep the vehicle from lugging or something. I need to experiment on a long trip to see if that is true.

Anywho, just thinking aloud and wondering if anyone notices the same.

[sirwm]

thanks for the details.

You will notice other threads where people basically have the
same info as you...

The MPG matches the temperature...
High temp, high mpg - low temp , low mpg

[dball711]

Those numbers dont seem too bad?

[wasabi21]

Your observations mirror mine. Driving in temperatures below 25° yields around vehicle rating of 22mpg for highway driving. Progressivley warmer temperatures yields progressively better highway mpg. Anything over 24 mpg seems pretty good for this size of vehicle. However, as you state, the instantaneous fuel consumption display does appear to be somewhat optimistic.

[jwalz1]

I was expecting SOME difference due to temp as you would in any vehicle, just not as much as 30%.

I think in all my searches the highest I have seen anyone claim was a tank at 27mpg. On a long drive on a hot day, I certainly believe it is possible, which is impressive. But I am still disappointed, again since this is primarily a winter vehicle for me, at the cold temp mileage.

Maybe if I am board I will rig up a ghetto snorkel to have the air box suck air right from off of the exhaust manifold and run that from October through March just for giggles.

[Dman1]

In the winter, with winter tires, I usually get around 14-16MPG, but most of my travel is in the City. In the summer, I am typically get 17-19 MPG with the same travel (mostly city travel).

Just looking at highway travel, without hypermiling and traveling between the speed limit and 10km/hr over the speed limit, I can get around 16-18mpg in the winter (with winter tires...i.e. more drag) and 23-26 MPG in the summer.

This, as well as what you are getting, are very acceptable for a mid-sized SUV, IMO. If you are not satisfied with this, there are a lot of other options for winter driving. I had a 2005 Camry with winter tires that performed amazing in the snow. I cannot recall my mileage, but I am sure that it would have been in the 30s (MPG) on the highway.