Well it has been a year since I have had my truck. All miles have been logged and MPG calculated at each fill. Here are the numbers and some of my own opinions at the end.

date----------Gallons Pumped-----Computer Mileage---Hand Mileage---------Notes
3/29/04________________________12.5____________________ _Picked up New
4/5/04________24.707___________14.0__________15.1_____ ___90% highway
4/9/04________10.966___________12.9__________13.7_____ ___80% city
4/17/04_______19.493___________13.7__________14.7______ __80% highway
4/18/04_______24.404___________14.4__________16.8______ __100% highway
5/1/04________23.663___________14.0__________12.88____ ___100% city
5/7/04________20.278___________14.1__________15.4_____ ___70% highway
5/16/04_______27.390___________14.2__________15.8______ __70% highway
6/2/04________23.911___________14.2__________14.8_____ ___50/50 city/hwy
6/13/04_______29.908___________14.3__________15.1______ __50/50 city/hwy
6/14/04_______24.402___________14.5__________17.97_____ __100% highway
6/27/04_______27.471___________14.4__________14.69_____ __50/50 city/hwy
7/11/04_______27.004___________14.4__________14.47_____ __50/50 city/hwy
7/12/04_______29.300___________9.2___________9.4_______ __100% hwy Towing 6000#
7/18/04_______26.320___________12.8__________12.5______ __75% hwy towing 25%
7/21/04_______30.942___________9.6___________9.26______ __100% hwy towing
8/2/04________29.465___________13.4__________14.24____ ___75% city
8/30/04_______28.422___________13.9__________14.5______ __75% city
9/18/04_______29.342___________14.5__________15.2______ __50/50 city/hwy
10/12/04______27.000___________14.9__________16.6_______ _75% highway
10/12/04______REFLASH TO TSB 18-037-04
10/16/04______15.408___________15.2__________13.8_______ _50/50 city/hwy
11/06/04______27.306___________16.7__________16.2_______ _50/50 city/hwy
11/24/04______22.277___________16.6__________16.3_______ _50/50 city/hwy
12/2/04_______32.274___________16.8__________15.07_____ __50/50 highidle time
12/28/04______27.697___________15.3__________15.1_______ _100% city
2/4/05________26.681___________13.0__________12.7_____ ___100% city highidle
2/25/05_______27.989___________16.0__________15.3______ __100% city
3/25/05_______26.390___________16.1__________15.9______ __100% city

Average computer before reflash 13.53 after 15.71 2.18 MPG Gain
Average hand before reflash 14.37 after 15.04 0.67 MPG Gain

For the parts that say towing, I was towing around a 6000 pound Travel Trailer.

90% of all fuel used was #2 Diesel other was unidentified but in this area im sure probably #2 Diesel

Fuel Tips
1.) Make sure you fill it up the same way all the time to have a good calculation. If you just assume it is full when pump stops you could be missing out on an additional 5 gals. Makes a big differance in the calculation.

2.) Avoid high idle times! These babies suck the fuel down as much sitting still as driving. Do your self a favor and plug it in on those cold days to help cut down on the idle time, will also help eliminate that white smoke deal.

3.) Want to see how well computer is to your hand calulations. Reset computer after EVERY refill. I didnt start doing this until I was well into my first few tanks but looks pretty close now.

4.) You here that turbo? If you do, you need to backoff a bit, burns alot more when you are spooled up.

All my Oil was changed with no more than 3700 miles on each change.

The truck

2004.5 2500 LWB 4X2 Cummins 600 Graphite SLT Pkg. Michellin Tires, 48RE automatic and the 3.73 gear in the rear.
Has a Century Royal fiberglass cap color to match

 

Excellent Work! You're numbers are right in line with what I'd expect (although like most people, I bet you wish you're avg. was a couple MPG more).

You're fuel tips are spot on! I would only add that it helps alot to coast as far as you can instead of maintaining your throttle position when you know your coming to a stop soon, completely back off. It should help alot.

 

man... you are on top of it, i will give you that!

i usually just check mine when i fill it up and forget it until the next time. looks like yours is about the same as mine though. i have noticed a dramatic increase in mileage in the last month due to different driving habits. once fuel jumped above $2.00 a gallon i have changed the way i drive so my mileage has changed to reflect that.

britt

 

i was a little leary of the 600 series because of mileage issues,,but i bought one anyway. ive been pulling a little boat for about 1/2 my tanks since new.ive averaged 16 point something,every tank.this last tank was my first that was all non towing,and it averaged 18.2.this is hand figured,,as i dont have an overhead in mine.the truck has 1900 miles on it now also.the only variance that may be to this is that i have the little puny 245`s on it for now that came on it,so there would be a small higher reading than with larger tires that most everybody has.but for now,,im highly happy with my new truck................bama

 

Well when I first got it I seen all the talk about MPG and how it improves over time so I fiugured I would log my mileage. So I will continue and maybe next year post another round of results.

 

ODO TRIP GAL PRICE $ / Gal MPG
677 608.7 34.814 $82.13 $2.3591 17.4843
993 316.1 23.538 $56.00 $2.3791 13.4293
1508 515.5 35.729 $83.93 $2.3491 14.4281
2054 545.5 34.675 $80.76 $2.3291 15.7318
2640 586.1 37.177 $85.10 $2.2890 15.7651
3177 537.2 35.391 $79.59 $2.2489 15.1790
3391 214.1 18.624 $41.89 $2.2492 11.4959
4001 609.3 37.144 $72.39 $1.9489 16.4037
4548 547.2 33.824 $65.92 $1.9489 16.1779
5125 576.4 35.332 $69.57 $1.9690 16.3138
5750 625.5 38.937 $81.44 $2.0916 16.06441174
6284 533.7 36.156 $69.74 $1.9289 14.76103551
6851 566.9 35.113 $67.73 $1.9289 16.14501751
7366 515.3 34.844 $67.21 $1.9289 14.78877282
7891 525.1 33.179 $65.00 $1.9591 15.82627566
8234 342.3 20.575 $40.51 $1.9689 16.63669502
8874 640 35.196 $68.95 $1.9590 18.18388453
9162 287.9 14.388 $28.62 $1.9892 20.00973033
9529 367.2 33.519 $66.67 $1.9890 10.95498076
10106 576.2 35.098 $72.27 $2.0591 16.41688985
10468 362.7 26.911 $58.10 $2.1590 13.47776002
10955 487.1 33.66 $78.10 $2.3203 14.47118241
11419 463.2 28.867 $66.94 $2.3189 16.04600409
11684 265 20.499 $48.15 $2.3489 12.92745988
12084 399.8 23.66 $55.10 $2.3288 16.89771767
12605 521.6 28.352 $65.75 $2.3191 18.3972912
13054 448.6 24.89 $56.72 $2.2788 18.02330253
13284 229.7 11.881 $24.58 $2.0688 19.33338945
13782 498.2 26.091 $55.29 $2.1191 19.09470699
14275 493.3 26.242 $57.44 $2.1889 18.7981099
14811 535.3 31.242 $68.08 $2.1791 17.1339863
15157 345.8 25.636 $55.35 $2.1591 13.48884381
15361 204.5 17.784 $38.04 $2.1390 11.49910031
15704 343.2 31.602 $69.49 $2.1989 10.86007215
16051 347 32.065 $71.47 $2.2289 10.82176828
16184 132.9 11.786 $25.92 $2.1992 11.27609028
16549 365 29.277 $67.31 $2.2991 12.46712436
16885 335.1 25.415 $55.38 $2.1790 13.18512689
17292 407.8 33.615 $79.30 $2.3591 12.13148892
17702 409.6 36.29 $88.51 $2.4390 11.28685588


So far my truck has eaten 1099.11 gallons at a cost of $2362.63, average of $2.1554 per gallon.
The best tank MPG to date is 20.009 set on 1/24/2005.
The worst tank MPG to date is 10.821 while towing 6K west over the rockies.
The average MPG is 15.08, including all towing.
The most I've paid for fuel so far is $2.439/gal.
The cheapest fuel has been $1.929/gal.

 

The only towing I have done is to Southern California and back home in foothills east of Sacramento, probably somewhat over 1,000 miles towing close to 14K. Every tank I checked was between 12-14 MPG which is considerably more than you show pulling a lighter load.

I don't know what speed you travel. I kept it between 55-60. I have had the same reflash and am puzzled as to what might make the difference.

j ripley

 

You were towing mostly flat ground between LA and here. On flat ground, wind resistance affects towing MPG more than the weight does. In my case, I was towing a 26' cabin cruiser over lots of mountains, so both the weight and the fact it's not very aerodynamic figures in. Every load is different, and to say "towing MPG" should be relatively the same is a stretch. BTW, I tow at 58-62MPH 90% of the time, only reaching the low 70's when I have to pass or if a big rig comes along that I want to slipstream for a few minutes. Speaking of which, I did a 10 minute computer MPG test on my road trip that showed me getting ~1mpg BETTER at 70MPH behind a big rig than at 58MPH breaking my own wind... might as well let them do the dirty work! Also, 90% of my trip across the US with the boat was in a 40-60MPH side wind. I had to turn my wheel 10-20 degree just to maintain a straight path.. that will affect MPG as well. Overall, this '05 seems to give me at least the same MPG as my '99 had, but I don't have to slow down for any hills! Man I love this truck!

 

Actually, we managed to find a lot of 'unflat' ground going: Sacramento-Pismo-Bakersfield-Tehatchapee-Yuciapa-San Diego-Grapevine-Sacramento.

j ripley

 

Ahhh.. that's a pretty route! Other than the grapevine, it's still relatively flat compared to driving over the sierras or rockies. Since you took the twisty route, though, that probably slowed you down some which tends to increase mileage for me... as long as it doesn't get toooo twisty, at which point you have to slow and go too much which sucks lots of fuel while towin. I averaged 12.5MPG going a similar route through pismo with my '99 towing my enclosed hauler full of toys. If you're getting 14MPG with 14K in tow, I would never sell that truck!!! I only get that if I can find a semi going ~60 or so that I can draft, but most of the big boys are haulin **** down I-5. BTW, what kind of trailer are you pulling? Is it wider than the truck? That's the problem with my hauler.. it sticks out almost a foot on either side. If I do it again, I'll probably get a V-Nose hauler instead.. should give me 1MPG back at least I'd think.

 

You are right on, twisty, but pretty.

We have an Alpenlite 32RL Versailles. Nice rig but not accurately named, not exactly 'lite'.


jr

 

Good reports.

Best I got ever was 20.2, empty on the flat prairie for 800 KMS or 500 MILES.
Worst I ever got was 9.2 with total weight of 33,800lbs, dragging two trailers, dead of winter, froze up breather hose, egt stuck at 1250, running 110-120 KMH or around 70 mph, -29 outside with windchill of -44. I really expected my mileage to be much worse. It seems like this truck levels off at around 10 mpg once I am over 20,000 pounds total weight.

I have a run to Denver and back in the summer. I will report back on that one too.
Expected total weight will be 20-21,000 pounds, pulling a dual tandem axle flat deck with strongman gear on it.

What spread sheet are you guys using?

Scotty

 

Man I would love to see 20 MPG. I think I drive too slow LOL

 

Bald Prairie, tail wind, went to the bathroom before the trip, forgot my luggage at home...it all added up.

 

Thanks for posting this Venom, you too Jeepdude. Venom, a couple of questions: What's your terrain like? Plains of the midwest, hills of CO, ect? How many miles do you have now? I'm not sure what "highway gear in the rear means" so maybe it's my answer, but which tranny do you have?

Thanks!