Fuel economy on full sized US diesel trucks - PeachParts Mercedes-Benz Forum

kerry · #1 02-28-2013, 10:13 AM

Anyone have general figures on what is normal? I talked to a guy driving a Chevy 4wd 2500 Duramax diesel yesterday as I was filling with fuel. He said he got 15 mpg but drove a lot in the mountains. I thought he would have gotten better than that. A former neighbor told me he got 21 or 22mpg from his late 90's Dodge Cummins pickup with a 5 spd standard transmission.

raysorenson · #2 02-28-2013, 10:22 AM

This is pretty subjective territory. Considering my driving habits and the local terrain, I will never crack 20mpg on any full size diesel ever sold in the U.S. market. The only ones I've heard of getting close to that were single rear wheel, 4x2 2 door cab manual trans vehicles. The new 6 and 8 speed auto trans equipped trucks allegedly can get better fuel economy than the manual trans trucks.
Expect 15mpg on all of them unless you're a "hypermiler".

capflya · #3 02-28-2013, 10:37 AM

I can get 20-22mpg easy if it's all highway. I have 33" mud tires and 20" wheels (heavy) so it's not as good as it could be. Before I got these wheels/tires I had some all-terrain tires on 17's wheels and one time when I was reeeally babying it on the highway I got 26mpg.

With that being said, my fuel is cheap now so I have paid much less attention to how I drive. I usually get 16-18mpg mixed and I'm not careful with the right foot. I have a 5" turbo back exhaust and I like to listen to it

Truck is a 2007.5 Chevy 2500HD Duramax 4x4. Tuned with exhaust but thats pretty much it for engine mods.

snookwhaler · #4 02-28-2013, 10:40 AM

I owned a 2002 Dodge 3500 Quad Cab Diesel 6 spd. Dually for years. It had the High Output Cummins and the NV5600 trans. Super Heavy Duty. I used it to pull a VERY heavy 5th wheel camper around. The camper was 15,800 on the CAT scale empty and around 17,000 full of gear and rolling down the road.

That truck returned 17 to 21 MPG in regular driving. Interstate driving at speeds over 70 MPH would knock it down to 16 MPG because of the gearing, width and extra rotating mass. Pulling that camper down the road returned 11 to 13 MPG at 70 MPH.

I did install 90 HP injectors, fuel pressure gauge and low fuel pressure warning system, Pyrometer, the improved fuel pump with the bypass circuit, turbo back 5 inch exhaust, BHAF air filter mod and several other things. It was a great truck. I should have kept it. Not sure what I was thinking when I got rid of it....

cornemuse · #5 02-28-2013, 10:46 AM

I had an '82 Chev w/ 6.2 & got 15-17 around town & 23 honest mpg on sustained freeway trips. '84 Suburban 6.2 about 3mpg less & my '84 Blazer (the hog) gets about 12 in town & I got about 17 + on a 250 mile trip (freeway) (lotta iron in that blazer 4x4) -corne-

JimFreeh · #6 02-28-2013, 10:52 AM

I've got an 89 Power Ram 250, single rear wheel, 4 wd, 5 speed Getrag manual, std cab, 8 foot bed. Slight oversize on the tires (265 vice 245/75), other wise pretty stock.

In the almost fifteen years I've owned it,I can expect 21-23 unloaded, 17-18 with a car and trailer, and 14-15 with the 27' Airstream.

Not sure how the newer trucks compare to mine, my brother hasn't gotten better than 17 with his 2009 F-350 quad cab 4wd.

It's not just the mileage, it's the torque that makes the diesel so great when towing.

Jim

rs899 · #7 02-28-2013, 10:52 AM

A good source of info is :

Fuelly | Share and Compare Your MPG

...taken with a large dose of salt.

DieselPaul · #8 02-28-2013, 11:35 AM

06 F250 8' bed crew cab 4x4 automatic.

18 avg unloaded. Seen as high as 21.

With an unloaded trailer 14-16, with a loaded trailer 14-16. It seems to be once you take the aerodynamic hit the weight doesn't seem to matter since I'm never pulling more than like 7000lbs.

Edited to ad, I like to run 75-80mph. People hate on the 6.0 but I've been very happy with it, keeping it stock seems to be the key.

daw_two · #9 02-28-2013, 11:41 AM

I use to own a 2000 Dodge Ram 2500 Cummins with the terrible 47RE automatic transmission. I learned anything over 69 MPH, and the fuel economy decreased. The 5.9liter Cummins sweet spot is about 1800-1850 RPMs; incidently, the 3.9 liter, 4BT Cummins sweet spot is about the same. Anyway, really babying the driving I could get 20-21 mpg, running stock tires and empty bed. I had the LONG bed; greater than 8feet --- yes, you can put a full sheet of plywood (4'x8') in the back and it still has a little bit of room to slide between wheelwells and between the front wall and tailgate. The most I ever pulled with it were the following pics.

When I was pulling the trailer empty going down I-65 from Birmingham,AL toward Pensacola, FL,

, my mileage dropped for sure. I picked up the Deutz 4 cylinder diesel (for sale!!!) in Pensacola, then drove over the Panama City and got all the rest of the stuff --- Perkins 3 cylinder diesel for sale & Waukesha 4 cylinder diesel for sale. On the return trip, my fuel economy was barely above 10mpg, but I figure the road was more hilly than my 2nd trip.

The trailer in question was a 20foot, 10K rated trailer with trailer tires. I always carried 2 spares, floor jack, and appropriate safety equipment. The second trip, I drove from home to Loranger, LA to pick up a step van. My return trip top speed was about 60MPH due to the trailer handling; anything above 64MPH and the trailer would start to sway. Stopping at the church was deliberate! I wanted to check the chains and say some prayers. My fuel economy was about 12 mpg on the return trip. I found it amazing that these wasps rode on the nest from LA all the way back to Memphis. It was raining when we loaded the StepVan, so maybe that's why they were all on the nest. They weren't very happy in Memphis; thank goodness they didn't have to live here too long.

Please note I have a flashing light taped to the rear of the step van for evening driving. I decided to sell this big trailer and if I ever get another big truck and trailer again --- the trailer will definitely be a gooseneck.

daw_two · #10 02-28-2013, 11:43 AM

Quote:

Originally Posted by JimFreeh

I've got an 89 Power Ram 250, single rear wheel, 4 wd, 5 speed Getrag manual, std cab, 8 foot bed. Slight oversize on the tires (265 vice 245/75), other wise pretty stock.

In the almost fifteen years I've owned it,I can expect 21-23 unloaded, 17-18 with a car and trailer, and 14-15 with the 27' Airstream.

Not sure how the newer trucks compare to mine, my brother hasn't gotten better than 17 with his 2009 F-350 quad cab 4wd.

It's not just the mileage, it's the torque that makes the diesel so great when towing.

Jim

Hey Jim --- do you think that camper on the back helped your fuel economy when you were towing cars?

Junkman · #11 02-28-2013, 11:57 AM

I get 16 mpg out of a 00 Dodge Ram 4x4 2500 with 5 speed (NV4500) and 4.10 gears. People whose opinions I trust get more but have higher gears. I'm stock but chips, injectors, tire size & engine/truck speed all have a large impact.

t walgamuth · #12 02-28-2013, 12:44 PM

I can get up to 22 highway solo if 60 or under, 20 to 21 if running 70 to 75 and 18 to 19 running 80.

Pulling a 30' award travel trailer from 11 to 14 depending on speed and wind.

Utility trailer empty about 17 to 18

with a 123 mb on back about 16 to 17

with a 39 studebaker on back about 13

flat towing a 123 mb about 18 to 19 running 80.

03 dodge 3/4 ton quad cab 2 wd cummins with six manual and 373 gears.

BobK · #13 02-28-2013, 12:48 PM

2000 Ford Excursion. Powerstroke 7.3L diesel 3/4 ton 4x4. 265 series 16inch tires. 3.73 rear end. Getting 13 to 14 right now combined mileage on winter fuel. On th eflat lands of Ohio with a/c off and cruise set to 65 (speed limit), I have seen over 20 mpg for mostly highway. Towing my 31' travel trailer, I get 9 to 10. My old '93 Suburban with 7.4/4l80E/4.10 got 5 to 7 pulling the same rig at 70 mph. You get much above the torque peak and diesels seem to start to really drink the fuel. They are real RPM sensitive.

vstech · #14 02-28-2013, 12:48 PM

My 94GMC 2500 6Lug 6.5TD longbed 2wd extended cab truck gets around 18 combined, and I've been told it'll top 22 on all highway... I've not had the truck that long to know... never done any extended highway driving...

SD Blue · #15 02-28-2013, 01:04 PM

With an old Ford 6.9L, I noticed the biggest difference when towing. It would get about 16 unloaded but would drop to 12-13 when towing a small 5th wheel and boat. The previous gasser, Ford 351, would get about 6 mpg, if that, with trailers behind it.

I usually ran 65-70 mph and never more than that. If you have ever had a tire go at 70+, while pulling a trailer with a single tire axle, it will take all you can muster to keep things in a straight line.