Question for Dodge Mega-Cab 5.9 cummins owners

[sledgreg]

I have a 07 mega cab, 34 inch tires 126,000 kms
cold air intake, 4 inch turbo back mbrp exhaust, and a smarty junior set to tow mode (setting 2) and i see on the highway 23 mpg and in the city 17-19 mpg.

In the winter with my winter tires on (stock) I can see 23-25 mpg highway 18-20 city

now if i set my truck back to stock with no smarty i see about 22 on the highway and 18 in the city.

It all depends on how I drive tho, If im an idiot with the go go pedal it will drop, but speed limit and its awesome.

I love the 5.9l

 

[347strokin]

I hear those Toyota Prius' get some pretty good gas mileage! Lol

Dodge front ends suck. You'll need a good aftermarket dual steering stabilizer, adjustable Trackbar if you have it lifted, and a steering box brace wouldn't hurt.

 

[TheHardWay]

One thing to consider: Don't rely on the overhead display for your mileage. Those things are always off, usually making your mileage look better than it is. Hand calculated is the only way to go.

I'm running a '07 5.9, 6" lift with 37s/20s, 3.73 gears, 6 speed manual, Smarty TNT, MP8, AFE CAI, AirForce intake elbow, and straight 4" exhaust. I've recalculated the ABS computer with my Smarty to adjust for the change in tire size, and the overhead "lie-o-meter" says I am getting 22-23 mpg highway, not towing at 70mph in the mountains of SW Colorado. Realistically, hand calculated I am at 17-18mpg empty, and 11-12 mpg when hooked up to the rock crawler or wakeboard boat.

I had a friend with a stock Toyota Tundra. Those things aren't anything to scoff at as they are pretty powerful. I think he got around 15 mpg unloaded, but when he hooked to the boat, his mileage dropped to 7-8 mpg.

I could drive a stock gasser, but I'd much rather have a Cummins, modified to my liking, and still get decent mileage whether I am towing or just driving around. Being able to pull a loaded trailer up a long grade without having to drop out of 6th always makes me grin. The power and torque of a diesel are addicting, which is why if given the option, I will never go back to a gasser.

Forgot to mention, I have around 63xxxx miles on my 07. 62,000 of those miles I have been running the 6" lift and 37s. I have never had a problem with my front end.

 

[srt20]

05 2500 4x4 cummins qdcb 285 tires, 3.73 rear, no lift, 104,000 miles, 5" turbo back, not cat, only a resonator for muffler. Its pretty quiet.
smarty usually run it on sw 5

have gotten 23 mpg driving nice and at 55 mph, usually get 17-18 mpgs because I drive it hard. I got 11-12 towing 11,000 lbs trailer.

Never touched the front end, though the swaybar link is getting noisey. Replaced all ujoints though.

Stock the truck got about 2-3 mpg worse empty.

 

[jfox1995]

I just put all new Moog ball joints and u-joints on the front end of mine and it still wanders a bit, these are what my local shop recommended. After I did this I heard about the Carli joints. I am going to try to find one of those steering braces and see how that works.

Thanks for the info.

 

[jfox1995]

One thing to consider: Don't rely on the overhead display for your mileage. Those things are always off, usually making your mileage look better than it is. Hand calculated is the only way to go.

I always hand calculate mine, although I have it figured out how far off mine is. When empty it is off 4-5 mpg from actual and loaded it is 2-3 mpg.

Thanks,
Jim

 

[jfox1995]

What does everybody run for gauges?

If I get a smarty or some other programmer other than Banks I assume I will need to add at least and egt gauge?

Also does anyone run one of those turbo timers that keeps the truck running until the turbo is cooled to an acceptable temp? Right now I just leave my truck running all the time when towing my trailer, unless I am stopping for the night. Usually our stops for fuel are only 15 minutes.

Thanks again, lots of great info.

 

[TheHardWay]

I'm running the Isspro EV2 gauges for boost, pre-turbo egt, fuel pressure, rail pressure, oil temp, and rear axle diff temp. They match the factory gauges pretty well, and Isspro has great customer service.

I also have a Edge Juice w/ attitude hooked up. I don't use it for any added horsepower. I use it for the turbo timer feature you mentioned. It's nice to shut the truck down and let it run until the EGTs cool to the temp I set it at. I use the display to monitor the after turbo EGTs, intake temp, % load, and throttle position. These parameters aren't quite as important, but since the monitor is there, I might as well use it.

 

[Vern]

not a cummins, but in my dmax I'm also running isspros. they have a pretty good reputation and u can usually find package deals a bit cheaper than the autometers.

 

[clarson80]

The best I have ever seen is 17 mpg empty driving like a grandma and 10 mpg towing my 25 foot enclosed trailer.

Those numbers aren't out of line with a 6" lift and 35's.

 

[himarker]

http://smartypower.com/new/smartyrevo.html

Add the smarty and some isspro gauges or a edge insight cts to monitor things. The cr 5.9's run well with a smarty. I know mine sure did.

Himarker

 

[07dragonguy]

The best I have ever seen is 17 mpg empty driving like a grandma and 10 mpg towing my 25 foot enclosed trailer. The trailer weighs somewhere around 6500-7000 lbs loaded. On the highway I stay around 70-72 mph which ends up being 1700-1900 rpm. I have heard that is the sweet spot for these motors.

I am not sure what you were expecting, as that is pretty good considering your setup. As far as the mileage and the premature front end wear you have alot of things working against you:

1. 35" tires on 20" wheels
2. You mentioned that your wheels stick way out from the fenders, negative offset wheels are no good for front ends
3. 6" lift

I have a 07 5.9 manual with edge w/attitude on lower tunes and see about the same numbers you see jacked up with big tires, so i would be perfectly happy with that if i were you. The 20-24 mpgs you read about on the forums are BS, unless they drive two wheel drives at sea level with no hills, and drive 60 mph everwhere, or unless they are highly modded (then not out of the question).

If you think that mileage sucks, don't but a new truck! I recently purchased a '12 dodge and it gets 12-13 in town and 13-15 highway!!!

As far as tuner goes, i would reccomend the smarty, and get the edge cts insight for gauges. Just installed the cts on my '12 and LOVE it! It will help mileage some, but don't expect to pick up 3-4 mpgs doing that alone. If you really are after mpg increases i would look at water/methanol injection - snow performance.

Hope this helps! If not there are lots of people out there looking for the 06-07 5.9s!!

 

[turboless terry]

06 mega cab with 6 speed manual. Worst truck I ever owned. 13 mpg. Put a bullydog programmer and it might squeak 15 if drove real nice. Great power but 13 most of the time. Worst truck I ever owned. Rear windows cracked out of it. Warrantied one but wouldn't do the other one. needed new tie rods in 30000ish. Heater broke in about the same time. Supposedly checked it and nothing wrong. Cost me $750 to fix and they wouldn't cover it either. It would be dead in the morning and they told me I had to take keys out of it. Never had a truck you had to take keys out of. Took keys out of it and, sometimes, it would still be dead. The service manager who new about all this, for Lithia, quit and went to work for toyota so I was screwed. Won't ever buy anything from them again. They all have good ones and bad ones but I came out of a perfectly good 04 duramax and just wanted better mileage.Lb7 was good and I had the lly. Dodge had better power and that was it. Not going to get 20 with 35's. It is a 2-3 mpg hit over a stock truck. To sum it up, my 06 mega cab sucked and Lithia dodge sucks.

 

[clarson80]

06 mega cab with 6 speed manual. Worst truck I ever owned. 13 mpg. Put a bullydog programmer and it might squeak 15 if drove real nice. Great power but 13 most of the time.

The g56 6 speed trans wasn't made for mileage, 6th gear ratio is way too low. There is a tremendous difference in the auto. It's asking a lot to get good mileage when the engine is 600 rpm's from red line on the interstate.

 

[rhalloran]

I have an 04.5 crew cab/longbed/6sp/4wd, stock size Duramaxes, Smarty JR set on "Towing," ATS exhaust manifold, aftermarket intake elbow, big, cold air intake (AFE, I believe), I get 20-21 highway unloaded (deck in bed), 17-18 with two sleds on it, and about 14-15 with a 28'/8000# toyhauler.

I lost ~1mpg going from Michelin LTX M&S tires to the Duramax.

Overall, I'm really happy with the mileage - pretty shockingly good for such a large vehicle. The best tank was 22.5 on the Michelins (overhead display claimed ~24.x), right now, overhead says 20.9, but 240 miles of this tank were with the sleds on it & a fair bit of time in 4wd. I'd expect this tank to work out to 18.xx.

No complaints. Not sure what bits to get, the PO of my truck did all the stuff, and I'm very happy with it. The OP's numbers don't sound awful to me, big lift and giant tires considered.....

 

[jfox1995]

First off some of you can't read. I said the truck had 35's with big offset rims on it when I bought it. I took them off and went with a positive offset with tall skinny tires that are nearly stock size. If tires are the issue it isn't the major one at this point.

Second I fixed the ENTIRE problem today when I traded it off on a 2011 Ford F350 crew cab longbox with the 6.7 diesel. So far on my trip home from the dealer towing my trailer I got better mileage than I did on the way up with my Dodge. So that makes me happy. Also it drives perfect, just as a 60k pickup should so that makes me ecstatic.

So thanks for all the replys and opinions.

Good riddence Dodge...effing pile.

Problem solved....thread closed

 

[rhalloran]

First off some of you can't read. I said the truck had 35's with big offset rims on it when I bought it.

Yeah, and you replaced them with tires 1/2" shorter. IE, 2"+ taller than stock.

"I have a 2006 Dodge 2500 Mega-Cab with the 5.9 cummins. It has a 6 inch lift kit and 20 inch wheels. My tires are 275/65/20."

You later mentioned the 35s, but whatever, 275/65-20s are pretty freaking gigantic.

Glad you solved your problem, though....