RV.Net Open Roads Forum: Tow Vehicles: Dodge 5.9 vs 6.7 Mileage

Print | Close

Topic: Dodge 5.9 vs 6.7 Mileage

Posted By: The LeRoys on 11/14/10 07:15pm

I have once again found myself looking at Diesel trucks. And I think I've stumbled upon what i think is a decent deal. But its on a 2007.5 Dodge truck. I had been looking for 2007 or newer, not wanting a 2007.5.

I know in Jan 2007 they changed from the 5.9L to the 6.7L engine for the emissions laws.

There seems to be a wide variety of opinions on how much worse the new engines are on fuel than the old ones. Does anyone know if there is a good site to compare these? Or have a quantitative comparison of the 2 engines?

I'm not looking for comparison on gas vs diesel, or dodge vs chevy vs ford. I'm just trying to compare these 2 engines.

Brian & Evie LeRoy and our 4 kids.
2013 KZ Spree 329IK
2006 Ford F250 6.0L
2008 Ford E350 v10

Posted By: trop-a-cal on 11/14/10 07:23pm

Since the ULSD is the only product sold now. The older vehicle is not designed to run on it and therefore will get worse MPG's. Then you don't know what rear end final drive ratio's are from one to the other, which also determines towing capacity and MPG's.

Posted By: troll3193 on 11/14/10 07:27pm

You will find owners of every general of Dodge/Cummins trucks at these sites and they will have all the thoughts and opinions you could possibly want..

http://www.cumminsforum.com/forum/

http://www.dieseltruckresource.com/dev/

The big difference I see in mileage is not so much from the 5.9l 04.5-07 to the 07.5 and on 6.7l, as the 5.9l 04 and earlier...

My neighbor has an 03 (305hp) Dodge/Cummins and it gets much better mileage than my 06 or my 04.5 did...

Bryan

2006 RAM 3500 MegaCab w/Cummins Turbo Diesel
Mopar Exhaust Brake
2004 Dutchemen 31BK

Posted By: tx racer 67 on 11/14/10 07:32pm

From what i have seen 5.9=18 to 21 mpg 6.7=13 to 16 mpg.Hwy

03 chevy
05 cruiser
67 camaro

Posted By: Maintcpo on 11/14/10 07:45pm

Just this week I got 17.6 towing my 28 ft 5er about 125 miles each way to the beach and back with about 200 miles around the local area. I have been averaging 20 mpg on my daily 30 mile each way commute to work.
No mods no nothin! 72K

Dan, Ret Navy CPO
Minnie The Wife Extraordinaire
2015 Sundance 245RL
2012 GMC Sierra 2500 4X4 DSL

Posted By: ALBE on 11/14/10 07:49pm

5.9 pulling approx 23000 lbs GCW srw 10-12 us .Never pull under 60 mph, mostly 65/68 mph.

Posted By: ScottG on 11/14/10 08:16pm

I get 10-12 pulling 8k TT. You Dodge guys shouldn't believe your overhead ~ it exagerates wildy sometimes.
Mileage has a lot to do with how well the injectors are matched for flow. It's hit or miss with the stockers but some honed aftermarket injectors are matched very close and actually get better mileage even though they flow more.

Posted By: Tom/Barb on 11/14/10 08:26pm

Maintcpo wrote:

That was about the norm with my 02 5.9er

2000 Newmar mountain aire 4081 DP, ISC/350 Allison 6 speed, Wrangler JL toad.

Posted By: MadMav on 11/14/10 08:27pm

tx racer 67 wrote:

From what i have seen 5.9=18 to 21 mpg 6.7=13 to 16 mpg.Hwy

Bit low on the 6.7l. I get 16.1 at 80mph with the big Ranchhand bumper on the front. This is stock, 8100lbs and dual rear wheels.

2500 quad cabs are getting up to 19mpg, but closer to 18 on average. Never hear of a 6.7l getting lower than 15mpg highway.

Mav

"A fifth wheel trailer is a bi-level towable mobile home."

Posted By: dodgebob08 on 11/14/10 08:33pm

calculated by hand:
i got 18 to 20 with my '04 5.9, with my '08 i get 16 to 18. towing, i get 8 to 10 mpg, that's driving the speed limit or a little better.

2008 Dodge 2500 MegaCab CTD
2006 Copper Canyon 295RLS
camping info

Posted By: handysam1 on 11/14/10 08:36pm

MadMav wrote:

tx racer 67 wrote:

From what i have seen 5.9=18 to 21 mpg 6.7=13 to 16 mpg.Hwy

I agree with Mav, I've never gotten below 18 on highway. I get about 11 towing 11,500 #'s

2007 Dodge Mega cab 2500 6.7 CTD
2011 327RES Cougar Fifth Wheel

Posted By: thomasmnile on 11/14/10 08:43pm

The LeRoys wrote:

If anything, the DPF (when needed) decreases the fuel economy since more fuel is dispensed when the DPF has to be cleaned (burned off). Dodge owners on this forum note the harder the truck is run, the less frequent the DPF needs "cleaning". If the engine sees low speed grocery getter service, the owners manual recommends driving it at highway speeds for specified time interval to minimize DPF regeneration cycles.

I own an '05 3500 with the Cummins. Mileage runs like this: 13mpg (city), 18-20 (highway unloaded), & 10-12 mpg towing the trailer, usually around 60mph on the open road. The truck has the 48RE auto. and 4:10 rear axle.

If given the choice, I would buy the 2007.5 for the VGT exhaust brake & the 6 speed automatic if that's how it's equipped.

Posted By: C Schomer on 11/14/10 09:40pm

My empty driving is always mostly city. I get 19.8 in the winter and down to 18.3 summer (AC always on). 12.9 towing. Craig

2012 Dodge 3500 DRW CCLB 4wd, custom hauler bed.
2008 Sunnybrook Titan 30 RKFS Morryde and Disc brakes
WILL ROGERS NEVER MET JOE BIDEN!

Posted By: Turtle n Peeps on 11/15/10 12:06am

Quote:

Since the ULSD is the only product sold now. The older vehicle is not designed to run on it and therefore will get worse MPG's.

What???

~ Too many freaks & not enough circuses ~

"Life is not tried ~ it is merely survived ~ if you're standing
outside the fire"

"The best way to get a bad law repealed is to enforce it strictly."- Abraham Lincoln

Posted By: RVnRobin on 11/15/10 06:24am

trop-a-cal wrote:

Since the ULSD is the only product sold now. The older vehicle is not designed to run on it and therefore will get worse MPG's.

Not true with my 1994 Dodge 2500. I get the same mileage before as after.

trop-a-cal wrote:

Then you don't know what rear end final drive ratio's are from one to the other, which also determines towing capacity and MPG's.

5.9L, auto trans, 3.something ratio... 11-13 towing and 18-20 w/o TT.

I plan on keeping it forever. [emoticon]

So much to experience, so little time.

Posted By: Turbo Diesel Dude on 11/15/10 07:26am

2005 2500 QC 4X4 48RE got 10.5-11 mpg towing 9500lb TT. 15-16 empty (hand calculated) with an occassional foray into 17ish. Overhead is an astute total liar!!JMHO. My 2008 6.7 six speed auto..........................10 ish towing same TT @ 62 mph. Empty 15-16 on a great day from 55-75 mph same deal. This THE TRUTH,ACTUAL, NO BS!!! Believe what you want.JMHO

charles weidman

Posted By: RRUGG on 11/15/10 09:28am

With my 5.9 I got up to 23 empty highway and 11-12 towing. It had 3.54 axle. With my 6.7 I get up to 19+ (but never hit 20) highway empty and 11-14+ (but never 15) towing. It has 3.73 axle. All results hand calculated and speeds RARELY over 60. Both trucks with auto trans.

RRUGG
2009 Chevrolet Silverado LTZ 1500 4x4 5.3L
2011 Kodiak 281RLGS travel trailer
2011 Egg Camper
2010 Chrysler Town & Country
Good Sam life members
Bob & Grace professional retirees

Camped in 49 states. Missing Hawaii.

Posted By: windellmc on 11/15/10 09:28am

04.5 to '11 should all be very similar in mileage unless you run a very light duty cycle where the DPF takes a lot of fuel to regenerate. The 2 OD gears on the 6.7L helps the 6.7L keep up on the highway mileage.

'03-'04 (305 or 245hp) engines should be 10-15% better than the 325hp 5.9. Engines older than 2003 seem to do even a little bit better. The body was more aerodynamic but the engine was probably just a little less efficient than the '03. 2wd is worth at least 1 mpg compared to 4wd on the highway when not towing.

Posted By: Arcamper on 11/15/10 09:44am

My 08 only does 10 mpg when towing our 10k lb 5th wheel and about 12 when not towing. Guess I should quit driving it like a sports car and see what happens.

2016 Montana 3100RL Legacy(LT's,Joy Rider 2's,disc brakes)
2014 Ram 3500 DRW Laramie Cummins/Aisin 14,000 GVWR
2014 Ford Expedition Limited, HD tow pkg
2016 Honda Civic EX-T
1999 Stingray 240LS
1994 Chevy 1500 5.7 PU
2018 John Deere 1025R
B&W RVK3600 Hitch

Posted By: NavyDood on 11/15/10 10:21am

ScottG wrote:

Sorry, but that mileage is not that good for an 03 towing that low of weight. Are your injectors aftermarket? If they are, then that is just the opposite of what you are trying to say.

windellmc wrote:

04.5 to 07 yes. 07.5 and newer reduced drastically. If you can be your own warranty, drop the DPF and EGR system and the mileage jumps right back up equivalent to the 04.5 - 07 trucks.

* This post was last edited 11/15/10 04:12pm by NavyDood *

- Retired Navy Chief
- Vanilla 04 2500 QCSB, 4x4, 48RE w/MagHytec DD, Smarty Jr, 4" Exh, Modded Air Box, Isspro Gauges, Quadzilla RPG w/fuel pressure, DynaTrac front, Coolant By-Pass Filter
- 06 Pilgrim 30RE2SLF-5 13,300lbs loaded. B&W Companion

Posted By: ib516 on 11/15/10 11:17am

The 6.7L mpg will be 20 to 30% less than the 5.9L overall.

From what I've read:
Towing - 6.7L will be only slightly worse (1 mpg or less)
City - 6.7L will be quite a bit worse (3-5 mpg worse)
Highway - 6.7L will be about 2-3 mpg worse.

Prev: 2010 Cougar 322QBS (junk)
02 Dodge 2500 4x4 5.9L CTD 3.55
07 Dodge 3500 4x4 SRW Mega 5.9L CTD 3.73
14 Ram 2500 4x4 Crew 6.4L Hemi 4.10
06 Chevy 1500 4x4 E-Cab 3.73 5.3L
All above are sold
Current: 07 Dodge 1500 5.7L Hemi 3.55 / 2010 Jayco 17z

Posted By: Madhatter1 on 11/15/10 07:08pm

Heres my 2 cents. I have an 05 5.9 and an 08 6.7 IN THE DRIVEWAY. I drive both. Thay are the same truck except the 08 is a dually. Both are longbed 4x4. What I am stating for mileage is longterm averages.

05 unloaded 78 mph- 18.5
Pulling a 16' cargo trailer 72 mph- 11
Pulling 39' 14K toyhauler 68 mph- 10

08 unloaded 78 mph- 15-16.5
pulling an overloaded 10 cargo trailer 75 mph- 11
Pulling 39' 14K toyhauler 64 mph- 10

The 08 unloaded varies a lot under the same highways at the same speeds. You would think that both would be higher with the smaller trailers. They are close enough to call the same on the heavy loads. The reason we drive a little slower with the camper on the 08 has to do with the camers tires. we no longer use the non dually for the camper. The 05 is at 200K and the 08 is at 100k.

Some more good info on earlier 5.9's. Mt 97 2wd extended cab auto long bed got as high as 21 mpg highway. My 98 was the same as the 05. My 01 with a manual was a solid 19-20 highway. The only towing info on any of those was 12mpg on the 98 pulling a 10K boat from FL to CT at 72 mph.

And in case anyone is wondering I can divide the miles I drove by the gallons I pump.

Posted By: LITEPHIL on 11/16/10 07:22pm

My 06 gets around 18-19 unloaded hiway. But I did 450 miles towing 10,000 lb receiver pull toyhauler with my buddy and his 11,500 fifth wheel and his 09 6.7 Mega cab and we got the exact mileage. Both are 4x4 and we did 65-70 the whole time. SAME EXACT.Both are perfectly maintained and we got around 10.5 mpg.
I do think the 5th wheel has less wind resistance.

2022 Chevy Silverado RST Duramax NHT
1954 Chevy 3100 Carryall 4x4
2008 Salem T23FBL
04 FXDL Harley

Posted By: Perrysburg Dodgeboy on 11/16/10 07:36pm

The best two years for the Ram with the CTD was 2003-2004, both have no emissions garbage.
The 2004.5 was the beginning of the emissions and the lowering of your fuel economy. Before I was laid off last Friday I was driving 128 miles a day and would tuck in behind a big truck and could run 32 MPG @ 60 MPH. Without a big truck to draft I was getting 27 MPG @ 65 MPH. Not to shabby for a 7200# truck!

Don

2015 Ram 1500 Laramie Crew Cab SWB 4X4 Ecodiesel GDE Tune.

Posted By: drc5900 on 11/25/10 11:26am

I get approx 14 MPG w/camper @ 60-65MPG, 13MPG @ 70-75.
Without camper: Avg 17MPG, city/hwy combined. Pls see truck info in sig. MPG calculated on paper.

@ Robsouth: While I basically agree with you (I prefer to just load up and go whereever...): Some of us like to budget and see where the money goes & how far the available $$ will get them, rather than staying home. I think a thread like this one can help people decide with the choice of a next vehicle.

* This post was edited 11/30/10 08:16am by drc5900 *

1997 Dodge Ram Cummins 3500 Dually 5.9L Turbo Diesel, Billeted Goerend Auto Tranny & Triple Disk Torque Converter w/Manual Lockup, 3.5 axle ratio.
1992 Jayco Jay Hunter 950, w/Homemade: tiedowns/dually jack adapters/long hitch, Hott-Rod, 700W inverter.

Posted By: boatms03 on 11/29/10 03:39pm

I have an '09 6.7 4x4 crew cab short bed, I bought it used with 35000 miles on. I get around 16.5-17 on avg around town and hwy mixture going to and from work. and a recent 200 mile trip one way and approx 75 mile in town miles, avgeraged 20.1 mpg for the entire trip (approx 500 miles total). all is figured on paper, not on computer. all mileage confirmed by gps as well.

2009 Dodge Ram 2500 diesel
2017 Sierra 381 RBOK

Posted By: jdubya on 12/16/10 08:17am

We have a 2003 Dodge 2500 4x4 - every time I verified the overhead mpg it has been right-on. We get 20 - 22 mpg on the highway empty but as soon as I put a small trailer behind it drops to 15. We towed a 39' 13000# 5er for three years averaging about 10.5 - 11 (very pleased) I traded for a 35' 10,500# Open Range and now we get 11 - 12 mpg (lowest was 9.6 highest 13.5 depending on the wind)

Posted By: steelpony5555 on 12/16/10 08:46am

Alot will depend on the rear end and if it is a 4x4 or 4x2. My over head is also pretty darn close to calculations. I know both my son and neighbor who have 6.7's wish they had my truck. My son has done all the deletes and now gets about the same as I do. My truck is a 4x2 short bed 4:10 rears. I tow a 12500 lb 5er at 65-70 mph and get 10-13 mpg depending on the wind. Empty doing 70 I get around 18 give or take a mpg. Here's my sons truck and as I said it has had all the deletes done and a few other things but still get 18 mpg hwy----Fast Diesel

14 Cedar Creek Silverback 29IK
10 Dodge 3500 Dually Laramie 6.7 Diesel
14 Chrysler 300
07 Pearl White Ultra Classic (My new Baby)

Texas Boomers---Stop by for a Margie some time!

Posted By: SWMO on 11/15/10 12:43pm

I don't push my '09 3500 hard and I get slightly under 17 on the highway consistently. That does include a fair share of grades.

2009 Dodge 3500 Laramie, DRW, 4X4, auto, 6.7L, B & W Companion.
Jayco Designer 34RLQS, Mor/Ryde

Posted By: robsouth on 11/15/10 07:07pm

I must be a real dummy... I have never thought about the fuel mileage as I am going "wherever" anyway and it don't really matter to me what the mileage was to get there and back home, as I would have gone anyway. Is it really that big of a deal as to 1 or 2 miles per gallon difference? If so, stay home.

"Sometimes I just sit and think. Sometimes I just sit." "Great minds like a think."

Print | Close