Diesel vs. Gas Mileage

[08flagvlite]

Hi Dave. My father in law has a 2006 Ram 2500 HD 4x4 Quad cab with the 5.9 cummins turbo diesel, and he gets 23 mpg.at 75 mph hiway, and tows a small trailer with a garden tractor 42" lawn mower, and still gets a steady 23 mpg. I'd like to trade him! He has a Coleman/Fleetwood mid sized pop up that's the biggest thing he pulls. He also said that the 06 was the last year made before the big diesel change that Dodge made, with the low sulphur gas and special fuel necessary to operate it. Randy

[Dave_Monica]

Thanks for the info, Randy. I had heard that the 5.9 Cummins got very good fuel mileage. I was wondering if the new 6.7L that replaced it is as good. I've read on other forums that the newer generation diesels are a lot cleaner and quieter but don't get near as good mileage as the older units. Hoped some of our members would be able to shed some light on that.

Dave

[michael t cayouette]

THE FORD F-250 WITH THE V-10 HAS GREAT POWER A LOWER COST THAN DIESEL, DURING THE SUMMER GAS TENDS TO BE $1.00 CHEAPER . THE V-10 DOESN't COST MUCH TO MAINTAIN. THE NEW 3VALVE SYSTEM GETS BETTER MILEAGE. IN THE END THE V-10 WILL BE CHEEPER TO OWN AND RUN

[acadianbob]

Totally agree with you Jeeper. A small diesel in a 1/2 ton would be awesome. Unfortunately, it seems that all of the domestic manufacturers have cancelled or delayed that option because of the extra cost of the motors and the higher diesel fuel prices. So, per my previous post, I'm hoping that the coming turbo gas engines will provide the torque characteristics that I am looking for. For me, torque is more important than peak horsepower. I want my torque below 2,000 not above 3,000. We'll see what the final package finally looks like but it is coming soon.

[rthrbelsewhere]

Here's my experience with my 06 dodge 5.9 TD:

First, a few facts
- 06 dodge ram 2500 quad cab automatic trani with 3.73's
- upsize tires from stock 265's to 285's running an all terrain tire.
- topper on the bed, open-faced air filter and box, amsoil full synthetic in ft and rr axle and transfer case, and quadzilla xzillaraider 2 power module
- Winter blend diesel hit the market sometime early November after the temps dropped below 30* at night consistently.
- 34 Gallon tank with fill up's being consistant (level, to the cap, blah blah blah)
- Never ever ever ever ever rely on that overhead for mpg reading, only thing that's good for is direction your driving.


I have an application on my cell called mileage monitor that helps me to track my mileage over time and here is the output from Sept 30th '09 to March 9th, '10: (NOTE: if i don't fill the tank to the top, it doesn't give me a mpg rating until the next time I do.)


Date (mpg)
3/9/10 (15.3) (Pulled the TT 65 miles round trip to a local campground, the entrance has a very steep grade 7-9%(?) and we climbed it twice. Rest of tank was to work and back, 100 mile r.t.)
2/23/10 (18.8) (work and back, 100 mile round trip, pt hwy pt city 5 days a week)
2/15/10 (17.8) "
2/2/10 (17.2) "
1/2/10 (17.8) " (Partial fills in December, so no data til now)
11/16/09 (17.5) "
11/7/09 (17.2) Winter blend diesel started somewhere in here
10/28/09 (19.3) Still summer diesel
10/16/09 (14.2) Pulled the TT 330 miles from Pagosa Springs to Greeley (via hwy 285 on the north/south) there's 3-4 passes along that way with avg speed somewhere around 65-70 in the flats. 7.5-8 hour trip.
10/4/09 (19.3) Drove to Greeley from Pagosa Spgs same@70-80 6.5hrs, empty
9/30/09 (19.6) Drove to Pagosa Spgs from Greeley same@70-80 6.5hrs, empty



With that said, the very best mpg i've ever made in a Dodge TD was in my 04.5 model, 6 speed stick, 3.73's turning 285's AT's again with an average speed around 60-65 mph empty was a trip from Durango to Greeley via Pagosa Spgs (trip consisted of travels between Bayfield, Durango, Mancos, Cortez, and then thru Pagosa back home and then to work and back a couple of times). On that trip, it turned 21.8 mpg (700 miles on a 32 gallon tank) and had enough to get back to the station on the way home. I have pics of the odometer, fuel gauge, and overhead mileage & hours because I couldn't believe it myself. But figure, on average, I was getting 16-18mpg consistently, no matter if i was traveling the interstates or driving to and from work. The mileage is always effected directly by your speed, 55mph with stock tires and empty would probably produce some nice results, but where in the heck would I be able to do that?

[rthrbelsewhere]

Originally Posted by 08flagvlite

Hi Dave. My father in law has a 2006 Ram 2500 HD 4x4 Quad cab with the 5.9 cummins turbo diesel, and he gets 23 mpg.at 75 mph hiway, and tows a small trailer with a garden tractor 42" lawn mower, and still gets a steady 23 mpg. I'd like to trade him! He has a Coleman/Fleetwood mid sized pop up that's the biggest thing he pulls. He also said that the 06 was the last year made before the big diesel change that Dodge made, with the low sulphur gas and special fuel necessary to operate it. Randy

You can buy the 5.9L engine up into the 2007.5 year release, then it switched to the 6.7L

They did the same thing in 2004.5 when they released the H.O. model (325hp/610tq) during the mid year.

[UpinAK]

A big thank you to all for this great thread. Two years ago I bought my son’s 2002 GMC 6L 2500HD Duramax with the thought of using it as our TT TV. I grossly overpaid him for it to help him out a bit. I have worked at home for 14 years now. The truck has 104K on it and I might put another 500 miles a month on it. It sits in a heated garage. I have the complete maintenance history and it has been well cared for. I took it in when I bought it and had ALL the fluids, oils and filters changed.
I’ve had a bit of buyer’s remorse over the purchase, but after reading this thread I’m coming to realize I should be grateful for it. It does not have the extended cab, but the wife and I hopefully can make do. We intend to haul a 33 ft Rockwood (or similar) with it within a year to 18 months from now. It’s rated for 12K so I shouldn’t have to worry about it hauling our TT. I’m sure it’s going to need some upgrades when we get ready to hit the road, such as new brakes, air suspension, lockable bed cover.
Thanks for all the info and the peace of mind that I made a good decision buying it from him.
Cheers,
RT & KT

[Jas]

There is a way to cheat and get the best of both worlds. If you can find an older diesel say 80's or early 90's you should be able to get it fairly cheap. The Dodge I have is a 93 cummings with 290k on the clock, got it for 2k a few years ago. The maintence cost on the older trucks is higher but if you add a 2nd tank you can burn the spent cooking oil from Mc D's to suplement the fule economey. I can lay hands to about 20 gal or so a week for free and it artifically boosts my economy from 11mpg (towing horse trailer, similar weight to a small 5th) to near the noral non-towing milage of 18mpg. The trick is to have an older diesel. The new ones don't like this setup (EPA mods and what not). You also have to either invest in a fancy automatic switching rig ($1,300 to $3,500) or build it yourself. For short trips of less than 50 miles there is no real benifit as you have to heat the oil before it can be uses (first 5-10 miles) and then purge on diesel agian for a few min at the end of the trip. On long trips it does help with sneaking past a few gas stations. Just a thought on how you can get the diesel power at the price of a gaser. You can google for Waste vegatable oil (WVO) diesel conversion and find a lot of good info.

[jay and jen]

The mileage is around 9-11 mpg when hauling a 31' TT (I had an 08 Rockwood 8296SS). I get around 16-17 mpg when empty on the highway at a reasonable speed. Otherwise it's 14-15 in town with the stop-go trafffic.

On the other hand, my father has an almost similar truck. His is also a 2007 but he has the 5.9 CTD. He has told me the mileage is about 2-3 mpg better in each situation.

I would think the emissions crap (DPF, EGR, etc....) are whats robbing me of the good mpg's

Anyhow this is my opinion.

p.s In a week the wife and I get our brand spankin' new 2010 Rockwood 8281SS 5'er.....cant't wait

[kvtaylor]

We have had both so I will jump in for what its worth. We now have a 2008 Georgetown motorhome which has the Ford V-10 gas engine. On the average, we get a solid 8 mpg at 62 mph. We chose the gas engine because of the price of diesel pushers. Since were up in the years, I figure about 12 years and we will quit traveling. Thats a short time when compairing the cost of a diesel motorhome to a gas motorhome. Now saying that, we also own a 2005 2500HD GMC crew cab(loaded). It has the duramax engine and allison trans. And yes, for a diesel engine, it was about 5-6000 more. But we needed it as I was towing a 38ft Montana 5th wheel. It replaced a 1999 Ford F-350. I have no regrets about the price, I was getting some 12-13 mpg towing the 14,000 lb 5th wheel. And with out towing, some 20 mpg on the highways. Now trying to sell it, the value has stayed high and were not going to give it away. There is very little buyers out there. We added a lot of extras such as chip, 38 gal tank, air bags, and electric brakes. So without trading it in on a top of the line gas truck, I am stuck with a diesel that I no longer need.

[TulsaSteve]

I love the 30 Valve V10. I averaged 6.8 MPG over a 450 mile stretch the other day and I can change the oil for about $25.

6.8 may not sound good, but I tow a 4000 lb Saturn and I was running hills and passes from the Grand Canyon into New Mexico with a full fresh water tank. I typically average about 70MPH when conditions are right, but on that run I hit snow, dust storms, dust / rain mix, rain, sleet, more snow, high winds... well you get the idea... So I'm guessing my average speed was between 65 and 70 to get 6.8MPG.

I just have to watch when my wife drives.. She is more aggressive and will keep it wound up to 75MPH so I need to watch the mile markers and stop for gas a little sooner. I'll take a nap and wake up looking out the passenger window at a semi driver wondering how a stupid V10 with an automatic is passing him going up hill.

Also I swear by the transmission brake on the V10. It's a little wonder. I can take 4% grades fully loaded with hardly a tap on the hydraulic brakes. My startup checklist includes tow/haul ON. 100% of the time. Wish I could reprogram the computer to turn it on for me.

Only mod I've made to the engine is a Bank's air intake kit, which just opens up the air flow into the engine. Once the computer adjusted, mileage went back to normal, but I have more power at lower RPMs and the engine has a much deeper sound, versus the high pitched whine. The engine sounds much nicer at wide open throttle and I got some super cool Banks RAM-AIR decals!