Ever since the temperatures started rising I am seeing better and better economy. I know gasoline changes at some point to summer blends, but over the last 3 months, as temps started hitting the 70's and now 100's, I am creeping up to 17mpg despite no change in drive or driving habits, and now running the ac more and more. Been a gradual uptick with every tank.

Does this motor just like the heat? Or do all modern motors run more efficiently in the heat?

 

It's not so much that engine like the heat, but they certainly hate the cold. Also, the summer blend gas will do it too.

 

I bet your tires have alot more air in them to, due to the heat...!!!
Tires running under inflated robs ALOTTA mpg...!!!

Colder engine also requires more fuel.
(remember the days when you needed a "choke" on the carb, it needed MORE fuel to start/run..!)

Gutty96 is right though... summer blend gas does help alot.

 

I believe that the engines run richer during the winter to prevent them from overheating from lean running. (Yah, I know that sounds odd). On a recent trip to Hawaii, I was driving a turbocharged Ford Escape DOWN Mauna Kea at about 12000' altitude. The temperature was in the low 40's and I was given a driver alert that "power has been reduced to prevent overheating". I was using engine braking at the time to try and save the brakes on the long 17% downhill run. I'm guessing this had something to do with the engine spooling up to 4000 rpm's with zero load (and therefore fuel) going to the injectors. In some way, this might be similar to what happens in our Hemi's during the winter.

 

Mine will drop to around 12 mpg's or slightly less during the subzero days of winter. Come summer/spring, my mpg's will run back up to around 15/16 mpg's daily.

 

Mine definitely changes. I've got a 28 mile commute to work, and will get around 16.5 MPG (according to computer) in the winter. It jumps to around 18.5 MPG when the temps get above 75 degrees or so.

 

Funny, because I would naturally assume hot weather would make things worse, but clearly I am wrong. If I can average 17 through the hot months I will be very happy.

 

Hot temps make the molecules in the air expand and there is less oxygen molecules per air volume. Our rams are set to mix gas to air at somewhere about 12.5:1 or 13:1. The way gen4 rams know how much gasoline to mix in when it's cold or hot, is by measuring the air density and air flow. So making this long story short, hot air means less fuel needed to get the air fuel ratio. This is magnified at high elevations where the air is thinner to begin with. This is another reason high elevation states sell low grade gas of 85 octane, no need for higher octane since the air is thin.

For those of us old enough to remember carburated cars, remember you had to retune the carb at high altitudes or you would foul the plugs? Also I used to rejet my motorcycle carburators to the elevation of the tracks I ran. Always carried a set of jets in the tool kit.

 

Last tank: 18.8 MPG (miles driven / gallons) and that's with the AC running full time. No complaints.

 

Absolutely AD, thats dam good bro...!!!