New to the diesel engine scene. Wondering what I can expect for fuel economy with a 2006 Dodge Ram cummins 5.9 regular cab manual transmission. Is 15-16 city, 20 highway realistic when not pulling a load and driving reasonably? I don't want to mod the truck, want stock performance expectations.

Thanks for your help.

hoaf

 

Yep, if not better!

 

I have a 06444 6 speed and can speak from experience you can expect about 16 period unless you baby it big time and dont break 55mph. I would reccomend some taller tiresat a minimum. I can get about 18 now at 65 on the hwy.

 

That's realistic. I was getting that mileage with my truck in stock format.

 

Do not expect 20 MPG unless you drive like Miss Daisy, not gonna happen. If you drive 70 on the highway, expect 16-18MPG. You hit the head on the in town estimates.

 

I've got the same truck. I get about 17.5 everywhere I go. That’s either city driving, or 75-80mph on the highway. I haven't gotten the opportunity to test all highway miles at 55-60mph yet. The worst mileage on a tank was pulling an overloaded 24' enclosed trailer at 75mph which worked out to be 11.75mpg. The best tank was mixed city/highway at 19.8mpg.

Mike

 

The killer for your highway mileage is the low gear ratios in the manual 6 speed. That is why the auto trans usually gets higher mpg than the manual. The 5.9 is much more economical if kept below 2000 RPM. That doesn't give you a very high cruising speed with the manual trans. An ideal solution is either a Gear Vendor (nicer) or a US Gear (less expensive) overdrive. These will bring you cruising speed up 20% (60 mph to 72 mph) at the same rpm. Taller tires might help, but they also work against your mpg by increasing drag.

 

Yeah,with fuel bound to keep going up I wish the manufacturers' would crank out a tall narrower tire without us having to go to 19.5's.

 

Not true! I run 70 and get 20+ on trips! I average 18+ combined 60/40 (hwy/town) The worst I've seen is 16 and that was towing my PT Cruiser, about 6k.

 

You guys are seeing way better mileage than me than, I get an average combined mileage of about 15.8 MPG. A lot of that is highway and secondary roads travelling at about 70 mph. The low 6'th gear ratio kills the mileage, I miss the mileage I got in the 99.

 

Well not a manual but my auto reg cab with 3.73 gets 20 mpg on highway and with city and highways i usualy get 18-18.5 cruising between 65-70 on highway. I bet it might get alittle bit better when i get my truck broken in only got 6K miles on her now

 

I average 18.5 hand calcs with my mpg mods. You should expect 15-16 mpg from a stock truck that's what mine was running. Also US Gear is not an option for G56 equipped rigs.

 

Yeah, I get +20 around town (I live in the sticks so it's not stop & go) but highway, unless you drive 65, you'll drop under 20mpg. I've noticed it going up (25k miles now) so occasionally with the right conditions I'll get 20+ highway but that's only < 70mph. It's just not geared for highway travel.