I'd be happy with the 13.8. But I'm talking real city driving where you rarely see above 40mph. If I have the money to use it for work its about 20 to 40 miles a day on Long Island in and around JFK airport. Worse roads in the country and stop signs and traffic lights every other block. Not to mention the occasional noisy riceburner that thinks he can take you at the stoplight because he has a real big plastic wing and a polished muffler to make him go faster. If I gas it real easy and I'm also in the habit of coasting in neutral a lot, I can just make 13mpg. When wifey goes out shopping with a lot of shutting off and restarting added in the car actually came back one time in the 9 range. We had a talk after that one. I have mannaged to get it up to 25 on the highway so I dont think there is a problem.

 

My site has a relatively detailed real-world fuel economy survey. Results for the Charger and Magnum here:

Dodge Charger / Magnum fuel economy

 

I have had mine 06 Magnum AWD R/T since Sept 2005.When it was first new and getting broke in I was avg around 14 to 14.5 MPG City driving and highway was 19 to 21 MPG. However, when the car broke over 25,000 km approx. 16,000 miles the fuelmileage started to increase. Even the Dealers and mechanics say to give the Hemiat least 20,000 km before she is broke in. I now have 40,000 km on the car and I get a consistent 16.0 to 17.0 MPG city driving and highway driving if it is fairly flat and speeds around 100 to 120km/hr (60 to 75MPH)I get on avg. 23.5 to 24.5 MPG.

When I had thefuel economy issuesat the start, I tried recalibrate MDS procedureif the battery is ever disconnected and that seemed to help. Also, ensure you ONLY use 5W20 oil as any thicker it will disable your MDS. The only additions I have done to my Magnum was add 20 inch Eagle Alloy Series 25 rims with Toyo Proxes ST's and a MOPAR CAI. The CAI really made the Hemi growl more than the stocker filter box. However, I don't think I gained anything in HP or MPG....if I did it was minor.


BBM99

 

Just turned 5500 on my 06 5.7, with factory oil change at 2500.

Stock, taking it easy at 65 MPH was 24.7 highway.
I flashed with SC 91 tune, and have hit 27 MPG highway.
Changing to a 4128 thermo, running 190 instead of 205, gave me 1 MPG.

Staying at 16-17 around town, taking it easy.

This thing bogs down till I hit >3000RPM, but liking the MPG right now.