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View Full Version : 2001-early 2004 LB7 Duramax Fuel Economy Poll



More Power
12-31-2004, 14:35
Fuel economy is one of the top 2-3 reasons why most people buy a diesel pickup.

What we want to do here is help determine what people are seeing for non-towing fuel economy in actual on-road use.

Let us know what your truck delivers.... This poll is for owners of the LB7 (2001-early 2004 model Duramax 6600 engines). We are assuming summer blend fuel.

You will need to vote before viewing the poll data. If you don't own an LB7, but would like to see the poll data, you'll need to first vote in the poll using the "Don't Own an LB7" selection for both the local driving and highway driving sections.

Round your fuel economy averages to the nearest whole number. For example a 16.4-mpg would be 16, a 16.8-mpg would be 17.

MP

[ 01-03-2005, 02:32 PM: Message edited by: More Power ]

Kennedy
01-01-2005, 07:00
I placed my numbers in the 15-16 off hwy, and 17-18 on hwy, but in reality, I run near 17 off hwy, and near 19 on hwy pretty consistently. I'm seldom down to 16 off hwy, and seldom in the low 18's hwy. Just did not feel that I quite made the next brackets...

BobW
01-01-2005, 16:42
More Power,
How about a second poll on mileage while towing. Might break it up into weight ranges.

More Power
01-02-2005, 19:31
Weight, wind drag and speed introduce a lot of variables when towing.... It'd be tough asking the right poll questions that would include all of the possibilities.

Open to suggestions.... :D

MP

Pfouts1001
01-02-2005, 21:43
MP, it might be good to run a 3 different polls for trailering, one for pulling gooseneck and tag open trailers (utility trailers, machinery trailers, and open car haulers), enclosed tag trailers (car haulers and rv trailers), and gooseneck/fifthweel enclosed trailers (Car haulers and rv trailers)... and then in each class break down into weight ranges ie.

gooseneck and tag open trailers
3K and under
3-6K
6-10K
10-14K
14K and up

Enclosed tag trailers
3K and under
3-6K
6-10K
10-14K
14K and up

Enclosed gooseneck/fifthweel trailers
7-10K
10-14K
14K and up

additionally, give the respondents an opt out for each weight category as you have done on this poll so that people may just view the post. This will allow people to respond to the weights which they most pull

just my 2 cents

More Power
01-03-2005, 13:06
What towing speeds?

MP

BobW
01-03-2005, 15:07
45-55 mph
55-65 mph
65-75 mph

Foley
01-03-2005, 20:01
I hope I see 19-20 MPG some day out of my truck. Be curious to know how many of the 19-20 range are stock and how many of those are 6 speeds.

Todd Manning
01-04-2005, 16:32
I just did an extended highway trip and purposely drove between 55-60mph the whole distance to check my mileage. Ended up getting 23 mpg (Imperial gallons), so this 19 mpg US (assuming my math is right).

2003 LB7 D/A with Magnaflow 4" exhaust and K&N air filter.

Todd Manning
01-04-2005, 16:36
I just did an extended highway trip and purposely drove between 55-60mph the whole distance to check my mileage. Ended up getting 23 mpg (Imperial gallons), so this 19 mpg US (assuming my math is right).

2003 LB7 D/A with Magnaflow 4" exhaust and K&N air filter.

TMS
01-05-2005, 15:26
Over the first 10,000 miles I could only get around 14-16. At about 10,000, everything seemed to run "free'er"....most recently a interstate trip back from Kansas in August running at 75+ returned 20-21 MPG !!! smile.gif

More Power
01-06-2005, 09:52
gooseneck and tag open trailers
3K and under
3-6K
6-10K
10-14K
14K and up

Enclosed tag trailers
3K and under
3-6K
6-10K
10-14K
14K and up

Enclosed gooseneck/fifthweel trailers
7-10K
10-14K
14K and up

45-55 mph
55-65 mph
65-75 mph

That's 39 polling questions, not counting the fuel economy range and "does not apply" selections for each weight/speed category. :(

MP

precision37
01-06-2005, 12:29
Total miles driven in 2004- 17,811
Total fuel used- 825.408 gallons
21.58 mpg average for the year. No complaints.
2002 GMC reg cab,4X4, ZF, stock. Very light towing and some snow plowing.

Scott Glewwe
01-10-2005, 11:12
I have noticed one thing not mentioned in the poll. In the summer months I typically get an average MPG (60% highway) of 17-18. However wintertime sees this drop considerably to the 14-15 MPG range. I assume this is due to the greater amount of "cold weather additive" used to keep diesel moving in the cold weather. Unfortunately for diesel owners here, Diesel is also at its highest price during the winter (competing with the fuel oil market). No big deal but my old 6.5L chevy never saw this big a drop summer to winter.

precision37
01-11-2005, 03:41
It's a combination of winter fuel and cold temps. The engine doesn't run a top efficiency until it gets up to opperating temp.
Cold weather slows this process down a lot. Sometimes if it is really cold, my truck never even gets over 180 degrees unless I'm on the highway for awhile. Don't forget about having to turn gears and driveline components in cold lube fluids.

Jim Brzozowski
01-13-2005, 10:16
Worst mileage recorded, 11.73mpg, gooseneck loaded GCVW=24,500.Best recorded 20.73.Running empty@ 68 mph.

Overall Average-49,005 miles, 2,736.93 Gallons=17.9 MPG. in 1101.1 hours=44.505 MPH lifetime average so far. I'm surprised it's that high. I did 453 offroad miles Hunting in Colorado, some it crawling through the canyons in 4 low. It ain't my old K3500 dully, but I sure like the fuel mileage better.

Kirkes
01-16-2005, 19:01
I would like to know how you can get over 17 mpg? I have never got more than 16.5 weather I baby it or not.

Corwin
01-17-2005, 23:21
17 to 20 most common

Check out results on this link below question (12), results of 61 people from 2001 to 2003 Chev/GMC owners

http://hobbycanada.qazam.com/Surv/Chev-GMC%202001%20to%202003.html

c5dura
01-20-2005, 11:03
I can't believe the excellent milage you guys are getting. I got 37k on my truck and have NEVER been able to go 400 miles on a tank. Therefore, I have never seen even 13mpg.

Dealer tells me that is perfectly normaly for a big truck like mine (see sig). Are there any other 3500 4x4 guys out there that have been able to break 400 miles on a tank full?

Inspector
01-25-2005, 18:08
I have a little over 17K on the clock now and solo average about 14.5 to 15. Never have seen much better than that on the average. I do have J/A installed so that may be skewing the numbers. Towing my heavy rig the milage will be between 9.5 and 11.5. I never drive over 70 with the fiver.
Denny

ibelyea
01-27-2005, 17:02
I have and 02 with "Edge" and never see more than 17.5 solo and 10-12 pulling my 5th wheel. I did go as low as 7.5 in North Dakota, but that was with a 40MPH head wind and 50 MPH. While I would like to get better mileage, I'm a little to heavy footed to really realize any better.

birddriver
01-28-2005, 11:38
At 75 on hwy, I am disapponted to see less than 22mpg at 60 I get 24mpg my city average is 17 with 28000 on the clock the only mod is a ventalated air box and a soft toneu cover

More Power
01-31-2005, 13:49
I filled up late yesterday. Fuel economy for this tank was 17.8 mpg - winter fuel in January. Pretty typical.....

MP

moondoggie
02-04-2005, 09:31
Good Day!

birddriver: Are you calculating your mpg from your odometer & the gallons you pump, or from an electronic readout in your cab? If you

moondoggie
02-14-2005, 06:52
Good Day!

birddriver: Please don't take this truck to your dealer, then get it back & tell us you now get 18 mpg - get it to someone who knows about these things & find out why you're doing so well, if that's possible. :D Then for those few of us where mpg is more important than snort, we can duplicate whatever you're doing or what's different about your truck. ;)

Blessings!

Brian Johnson, # 5044

PONCH
02-16-2005, 08:52
Last year (winter) I went on a 6000 mile trip towing my 28.5ft tag loaded at around 9000lb. I drove the northern route to Phoenix, flagstaff and down,then the southern route back to IL
Going out I averaged 70mph coming back was 60mph. This was hand figured at every stop as well as at the end.
Without towing and traveling I run 72 and will get 17.5-18 around town and normal driving I get 18-18.5

DA_MAXX
02-16-2005, 13:48
03 d/a, cc, 41K miles. Consistently average 18mpg. Haven't seen anything over 20+. I filler up to the top of the cap everytime and calculate the mileage manually. Daily driver, 38 miles one-way to work, 97% freeway, doing 70mph. No performance mods. Have had 1 injector replaced and 1 allison tranny replaced.

Spartus
02-20-2005, 13:00
22mpg Highway @ 80mph.
17.5mpg mixed driving.

14-16mpg towing 6,000lbs @ 75mph.

I tow with Attitude set at level 1. Stock exhaust, stock air box....

Hottruck
02-21-2005, 07:49
Hey all,
I've never gotten better than 14.5 mpg D/A and I'd like to know what I have to do to improve. I've got about 35,000 miles now..
Thanks for any input... :rolleyes:

birddriver
03-09-2005, 08:29
SORRY for the long delay in a reply.
A few times I have checked the mileage by hand.
mostly it is of the DIC. Fuel used is always within a 1/10th or so from what I refill to.
I always fill it to the brim so there is no guessing in that.
When I modified the air box I Removed three sides leaving the engine side,bottom and the four corners, also removed the foil patch from the inner finder. Then I smoothed the top and heavly blended the air tube transition and blocked off the little bulb "do-hicky" at the other end.
I use No additives or synthetic oil.
The best I can say is that the LORD has blessed me with a good truck!
Please note: My truck is TWO wheel drive.

jjackson
03-15-2005, 11:18
Birddriver, can you provide a little more info/detail regarding what you have done to your airbox. i.e., (I smoothed the top and heavly blended the air tube transition and blocked off the little bulb "do-hicky" at the other end)

Thanks, John

MIKE MOG
03-21-2005, 10:36
HEY DA_MAXX, WHAY DID YOU HAVE TO HAVE THAT ALLISON REPLACED? [NOISE]?

moondoggie
03-24-2005, 06:00
Good Day!

Thanks, birddriver. Guessing your airbox work & 2WD are helping lots. Sure wish I had some time to play with my junk

birddriver
03-24-2005, 08:17
Using a Dremal tool I removed all the cross hatch support from the top lid and smoothed it. The air tube transition needs to be rounded as much as posible if you cut to much You can use some of the now scrap and a good soldering iron to weld up holes.
((((( Take the MAF sensor out of the air tube BEFORE you begin )))))

MikeT
03-25-2005, 03:48
I regularly get 18.6 driving back and forth to work (100 mi per day 60 Hwy/40 City). On the open hwy, the mileage is directly related to speed.
Spd/Mpg
60/24
65/22.6
70/21
75/20.2
80/18

The truck is 100% stock 2002 DA 2500HD CC LB. I run AmsOil 15w-40 synthetic oil and a OEM style K&N air filter.

Mike .T.

gravity420
03-31-2005, 15:44
2 years ago I drove from Reno, NV to Anchorage, AK on $232.00 worth of fuel, mainly due to the fact that I only had $240.00 left on me and I was forced to drive this thing like grandma to church. At an average price of I am guessing around $1.50/gal back then divided by 3200 miles or so it comes out to about 20.5 mpg. This is seriously babying it, never acelerating hard from a stop at all and driving at a max of 70mph with the cruise control.

I think that some of you never see over 16-17 mpg because you are as addicted to the right pedal as much as I normally am and enjoy the power and fun that these trucks offer. Those experiencing the high mileage are babying it, never accelerating hard and never drive very fast.

I have also driven about half way thru Canada coming down from Alaska never going under 90 mph and let me tell you I only got about 350 miles per tank. Once I realized how much my speed and acceleration affected mileage I was forced to backoff because at the rate I was going I could not afford the fuel. Then I got up to 600 miles per tank.

So speed and acceleration makes a huge difference. For those of you never getting great mileage, don't feel bad, you are just driving the truck the way it is meant to be driven. There always is a trade-off between mileage bragging rights and having fun, and I suspect that it is way more fun to get worse mileage than it is to drive this truck like a model T just to say how good of mileage you get.

One thing to remember also is sometimes the electronically controlled torque converter slips more than it should, and the truck can feel sluggish and mileage can drop down to the 10-12 mpg range. When this happens, and it happened to me once, if you do the tranny reset sequence, which is going 50+ and shifting to first and bringing it down to a stop 3X in a row it will reset the computer and Voila, the mileage and power is back.

Shorty
04-08-2005, 11:57
Thought I would add to the mileage info,just bought used 2002 Silverado C/C D/A.Am getting 18mpg empty hiway,17 around town short trips,Towing 28' Jayco probably around 14-15 thousand gross 11 mpg through Texas and I-40 into NM turned north into 30-40 mph headwind to Alamosa Co. 9mpg. Came across mountains into Grand Junction 12 mpg I would like to do better but am satisfied so far. The D/A will certainly pull,Let the Allison do it's thing,dropped out of overdrive occasionally in the mountains and strong headwinds.Running 60-65 mph Shorty

Jim Brzozowski
04-13-2005, 08:48
I didn't see anyone mention this so I will. Its not only your rate of acceleration that counts for fuel mileage, its also your rate of deceleration. I suspect that is where a lot of you are loosing out. With these high compression engines if you just jump off the accelerator you are wasting a lot of energy stored in the velocity of the vehicle. You've spent the $$$ to get it up to speed which is where most of the fuel energy is used. It doesn't take much to hold a steady speed. To keep from loosing more fuel mileage decelerating try just backing off a little until you see the speedometer just start to decend. Try to keep the rate of decent in the area of coasting, where you are not using the engine to drag down the vehicle speed quickly but a just supplying enough fuel to keep it at a rate of slow decent. Your best mileage will be when you accelerate and decelerate at a slow rate and cruse at a steady speed for hours at a time, like out in the middle of nowhere. Remember its the rate of change that makes the difference. Food for thought.

Rocinante
04-17-2005, 05:10
For all of you using chips/programers, remember your truck DIC MPG reads too high when using chips/programers. You have to calculate the MPG the old fashoned way. By the way, the DIC Gallons used display also reads inaccurate, too low, you have to use the pump reading when doing you MPG.

okeehandyman
04-19-2005, 08:53
I purchased two 05 trucks in nov & dec 04. both are 2500hd 4x4 d/a's one cc & one ext c. I drove each of them kenosha, wi. to florida. they both got 22-23 mpg for the whole trip. now one has 13k miles and one 6k mi. one is avg 16 mpg and the other 17 mpg local driving. when we drive out of town & run steady we see much better mpg, as expected. the secret,i think,is keeping your foot from showing you how much power is under the hood! i carry a lance 915 truck camper sometimes. with that,i get only i5mpg on the highway - but i keep the speed down to 60 to 65.

goodmonkey
04-21-2005, 18:43
Unfortionatly I'm within city limits and not far from work, so I average 20 city miles daily back and forth in my 2001 Silverado. So that puts me somewhere about 13 mpg. Over the highway though I get between 17.5 and 19, traveling at 70 MPH. I'm sure the camper shell is helping cut into that. But for the size of the vehicle it really isn't bad.

EZ39e
05-04-2005, 14:52
2001 3/4 ton, 19 combined 25 highway. These are documented from 0 miles to over 100,000. Highway speed is 70 MPH.

Cracker65
05-30-2005, 05:19
With 34,500 miles on the odometer, and towing a 8,400 pound Airstream trailer, I'm getting 13.7 mpg in hilly country at 65 mph and about 14.7 mpg on the level. Solo, I get about 19.1 mpg at 65 mph on the level and about 16.8 in the hills. Around town (---mostly level,) I average about 14.5 mpg running solo. The truck has a hard fiberglass tonneau with a normal 500 lb cargo load in the bed - for an all-up weight of 8,400 pounds (---same as trailer.) These numbers all go down about 1.5 mpg using winter fuel blends in Maine.

2003 GMC 3500 Duramax CC, LB, 4WD

Driveshaft
05-30-2005, 14:30
I JUST RECENTLY DID SOME MILEAGE CHECKING. EMPTY WEIGHT IS 7000 LBS. GOT 18.7 MPG CRUISING AT 65 TO 74 MPH. TOWING EMPTY 4000 LB. TRAILER GOT 14.3 MPG, LOADED WITH APPROX 4000 LB. JOHN DEERE TRACTOR, 11.7 MPG. COMBINED TOWING SAME TRAILER LOADED AND EMPTY WAS AN EVEN 13 MPG. THIS WAS DONE OVER APPROX. 600 MILES. TRUCK IS STOCK WITH SWISS CHEESE AIR BOX. ALL HILLY AND FLAT GROUND. TRUCK IS '01 2500 WITH DURAMAX/ALLY COMBO. SPEED WITH LOAD WAS AGAIN 65 TO 74 MPH.

Driveshaft
05-30-2005, 14:34
ALSO, FORGOT TO ADD THAT MOST WAS WITH CRUISE CONTROL ON. WHEN TRANNY STARTED DOWNSHIFTING ON HILLS I TURNED OFF CRUISE AND DROVE WITH FOOT AND IT DID NOT DOWN WHEN I WATCHED MY SPEED, WOULD BE DOING AROUND 74,75 AT BOTTOM OF HILLS AND AROUND 66 TO 70 AT TOP.

canucktravellers
06-20-2005, 10:39
Towing Yes No
US MPG 12.53 16.56
Cdn.MPG 15.05 19.88
L / 100 Kms 18.75 14.19

1.) Done over 50,000 Kms, over two years.
2.) Tires changed to 265 and Speedometer out by 5% ie under running by 5%
3.) 160 Fillups.
4.) Traveled all over eastern Canada, Florida, Texas.
5.) Towing a 37 foot Titanium Fifth Wheel.
6.) Truck is an Extended Cab with a RETRAX Tonneau & Stock Tailgate.
7.) Fifth Wheel weighs 11,400 Lbs.
8.) GCW is 18,400 Lbs

Cranke578
06-23-2005, 15:53
Hi I have a 2002 3500 4 wheel drive crew cab dually stock with edge jucie set at 90 hp. I get aprox 440 miles per tank before the feed me light comes on (30 gal.)empty town/city driving or 13 mpg. I tow a 36 ft gooseneck race trailer and get aprox 10 mpg consistanly. I do not baby it and I drive & tow at 70mph.

I have been disapointed in the milage until I see other Duallys in the same "ballpark". Those extra tires and wider areo do hurt rolling resistace.

BobNelson
06-25-2005, 05:54
82,000 miles now on six tires, and overall with fairly meticulous records, I have 13.85 mpg. With the camper on and toy box behind, seems like the average is about 11. Best recorded hwy empty is 18.2, but generally about 15.5

Mark Pearce
06-28-2005, 08:08
Lead foot Average.
75 MPH Highway
Almost legal around town
Avg 15.5 MPG
All Unladen.

Olden_B
07-05-2005, 06:10
I have been amazed by those who post that they are getting better than 15MPG highway or other. I currently own two 6600 durmax's 2004 models, in silverado package Z-71 4X4 crew cab/short box 2500. Both have recently been put through the 30,000 mi program, at a cost of $700 per vehicle. NEITHER of my trucks which are almost exclusively driven on the highway get better than 13.5 almost always 12mpg. with cruise control on at 70. Does anybody have a clue why they are both getting such poor fuel economy. My local dealer has put them both on the computer, replaced the fuel regulator on one and the injectors on the other and still there has been no improvement, and an actual reduction in performance of the other. HELP??
Thanks!
Bill

Originally posted by More Power:
Fuel economy is one of the top 2-3 reasons why most people buy a diesel pickup.

What we want to do here is help determine what people are seeing for non-towing fuel economy in actual on-road use.

Let us know what your truck delivers.... This poll is for owners of the LB7 (2001-early 2004 model Duramax 6600 engines). We are assuming summer blend fuel.

You will need to vote before viewing the poll data. If you don't own an LB7, but would like to see the poll data, you'll need to first vote in the poll using the "Don't Own an LB7" selection for both the local driving and highway driving sections.

Round your fuel economy averages to the nearest whole number. For example a 16.4-mpg would be 16, a 16.8-mpg would be 17.

MP

redrider#1
07-06-2005, 09:25
Olden, I am in the same boat as you. I just purchased a 2004 Silverado, D/A, crew cab, 4x4, long box and even though I have put few miles on it, I am getting nowhere near the mpg that everyone else has been reporting. So far I have been getting about 13-14mpg totally unloaded highway miles at 75mph. As I have a broken leg right now I have not been able to investigate further(air filter, fuel filter, etc.) What gives?

Mudflap
07-12-2005, 01:28
Around town I can't keep my foot out of it 15-16 mpg tops. On the road I set the cruise between 1800 and 2000 rpm 19-20 mpg all day, drops off a little in the mountains. 107,000 miles

FireMedic
07-17-2005, 17:27
Received Truck Dec 9, 2000 7 miles on OD
As of 7/15/05:
Mileage: 93,262
Hours: 2704.6
MPG Average: 16.6
(SF Bay Area Commute Traffic Range from 15.6 - 19.0)
Best Tank: 22.0 Road trip on cruise at 69mph

hotwelder5
07-24-2005, 09:42
names tony
I have a 2003 2500 with the edge extreme ,6"lift 35" tires 4" magnaflow exhaust & K&N filter & in town i get about 18 & 21 on freeway at 80mph, Im a happy camper, also 16mph towing my 21 foot boat up hill.Again very happy

dmaxster
08-30-2005, 17:56
with 124,075 on it I get an average of 19.2-20 hwy if I taker easy....driving around 60. at 70 i get 18.5 and city hwy I get 17.9 .... all and all I am really pleased. when I towed my buddy's gooseneck we weight GCVW 22,500 LBS then I was getting around 12 maybe 10 if Windy and Hilly but usually 12 MPG. All I can Say is SMILE EVERYTIME I start this BABY !!!!! :D :D :D :D

chrisinkanata
09-10-2005, 03:19
With very conservative driving i.e. 100-105km/h (62-65mph) unloaded over long distance consistently 26.5-26.9 Imperial mpg (22.4 US mpg). I have repeated this many times in the warm summer months with the stock 245's. BTW...speedo out by 2-3 mph according to my GPS. Understandable though since the tires are almost done and will be replaced over the winter while the snows are on the truck.

Towing - 7000lbs travel trailer (truck has a cap tapered up towards the rear and acts as a very good windbreak) ---- again very conservative driving and 18.3 to 19 Imperial mpg depending on terrain. (15.2 US mpg).

City summer driving same as towing.

I do notice that when I put the snows on (265's) the milaege takes a substantial hit. Empty hwy falls to 21-22 Cdn (17.5 US mpg). Two parts to that I think....larger tires (I use the GPS to record distance, not the odometer) and far colder temps. I wanted to replace the 245 summer tires with 265's but don't think I will based on that difference. I should put the snows on now while it's still fairly warm and see what the mileage is like.

Chris

AlaskaDmax
10-18-2005, 18:55
2002 CC/LB
Best HWy --- 21mpg normal is 19.5 to 20.
Day to day driving is about 22 miles each way, half hwy at 80 mph and half city stop and go = 16.5 to 17 mpg. I get 540 miles out of a tank if I push it to fumes on an average tank. I drive like an idiot, hard acceleration (2800 - 3000 rpm)from almost every red light. I have tried to keep it under 2000 rpms for a full tank, just to see what kind of economy I could get but I can't do it...I am too weak.
Lowest I've ever seen is 14 mpg on the Hwy...bro in law was drafting me through Nebraska...he said it was the best mileage he ever got!!!!!

mhagie
11-05-2005, 07:28
Bought truck last saturday(10/29/05)in central Indiana drove it home to SE Iowa 439mi @ 19.4 mpg
Not going to complain.
Merle

TRPSHOOT
11-11-2005, 05:45
Alright this isn't scientific or anything but this is what I came up with. I just drove from near Indianapolis to near Gunnison, Colorado for our annual elk trip. I reset the computer stuff to zero on the personal trip option (DIC).

I have 22,000 miles on my extended cab 2003 with 265 tires.

I weighed the truck empty and with trailer, full tank of fuel each time.

Truck weight with tool box, full tank of fuel, and no people= 6700 pounds.

We ran about 66 mph out there and according to receipts and old fashion math that = 17 mpg. Oh yal the utility trailer is a dual axle that we stuffed 3 quads on with other junk for a weight of 5200 pounds loaded.

Total round trip= 2634 miles

computer says = 14.0 mpg average

receipts and my math say = 14.8 mpg

average mph = 48

computer says 188.3 gallons used

receipts say 190.5 gallons used

There were about 10 times in Kansas that we were bored and kept the spedometer on 60 mph and then started the timer at the mile marker, consistantly we were at about 58 - 59 seconds. So if the spedometer is not already calibrated for 265 tires, then it is pretty darned close.

We were camped at 10,000 feet so says the GPS units we had. I took the truck back on some pretty rough 2 track trails with some really steep hills. The DMAX never missed a beat and I love that allison how it holds it's gear going down severe grades and hills.

The only thing was that when I first started the DMAX in the morning, it would smoke until engine warm up. I don't know if this is a faulty glow plug or what. Temp was around 19 degrees before sunrise. No smoke after engine operating temp was obtained.

The tranny temp stayed below 200 the whole time with the exception of the last 5 miles of the trip going up some really steep 2- track trails pulling the trailer.

This is a stock truck.

I am thrilled with the performance of this truck.

P.S. The Ford 10 cylinder gasser that accompanied us, got 8 mpg towing a 1700 pound pop-up camper. :D

sjd_sd
01-24-2006, 20:27
My mileage ranges from about 16 to 20. 16 happens with lots of 4wd use, deep snow and slow driving. 20 happens at a steady 65-70mph on the highway. I have a camper shell and one-size-up from stock tires. The price of diesel makes me wonder if it was worth it. Fuel for a gas-burner is about 40 cents less locally, so its almost a wash.

schaack2
01-28-2006, 20:12
Just checked my 2003 crew/short box today and I got 17.3 - only current mod. is 4" exhaust. This tank I just check I had been pretty heavy on the throttle with a lot of town driving. Previously checked tanks were high 18 / low 19 (all calculated manually).

After reading through all the differences in fuel economy, I'm curious which variables make the biggest difference in fuel economy. I've got a laundry list of upgrades to make, regardless of economy, I want to make larger burn-outs!!

How much affect do you guys feel a bed cover or topper makes on fuel economy? I've never had one on a truck but it has to significantly reduce drag (at least one would think). After reading all posts, two of the guys with the best economy had either a topper or a bed cover. What are the thoughts of everyone else on this matter?


Schaack2

SDakDmax
03-02-2006, 21:19
19 to 20 going 55 - 60 no problem, if I get my foot into it and go 75, it will drop to 16.. I think this is good.. the best part is the power when you get your foot into it, and towing..

diesel dissapointed
04-13-2006, 11:53
I hope this post saves some poor guy from thinking he can get the mileage #'s some of you guys are posting.I am on my second duramax after lemon lawing my first one.Total mileage over 100k and neither truck ever saw over 17mpg,that includes empty, downhill,tailwind,drafting,etc.This is a reg. cab 4wd 9,200 gvw truck that usually runs 65-75 with cruise control @ sea level.P.s.I've been a professional mechanic over 30 years and this truck has been on the dyno and had parameters checked with a tech 2 @.worst mileage was 9mpg towing 10K lb boat

DRINKDIESEL
05-11-2006, 13:12
Getting an easy 20mpg highway. Up to 23 on longer trips with '04 EC LB 4x4 SRW and the Juice with A2 set on milage(#1). Also installed a K&N air filter and modified the stock air box which helped a bit. I'll keep working on it.

DmaxMaverick
05-11-2006, 13:19
Getting an easy 20mpg highway. Up to 23 on longer trips with '04 EC LB 4x4 SRW and the Juice with A2 set on milage(#1). Also installed a K&N air filter and modified the stock air box which helped a bit. I'll keep working on it.

Just curious.
Is that mileage from the DIC, or are you calculating manually?

DRINKDIESEL
05-12-2006, 13:04
From the DIC. I was getting ~17 before the mods on the DIC.
I'll calculate it out on the next fill up.

DmaxMaverick
05-12-2006, 13:27
The reason I asked, is when using a power adder, the DIC tends to become quite optimistic. Usually, a very disapointing reality is discovered once the mileage is calculated manually. This inaccuracy is normal and consistent with the operation of the module/programmer. Problem is, the manufacturers don't disclose this in their literature. Most folks just go on thinking the mod has given them great mileage.

Please get back to us with your results. Some folks reported the DIC mileage was still accurate with a module installed. If one can do it, they all can. There's no reason to not have the DIC calibrated, if it's possible. In either case, we should either have a calibrated DIC, or a formula to determine actual mileage from the DIC info.

DRINKDIESEL
05-15-2006, 11:36
The reason I asked, is when using a power adder, the DIC tends to become quite optimistic. Usually, a very disapointing reality is discovered once the mileage is calculated manually. This inaccuracy is normal and consistent with the operation of the module/programmer. Problem is, the manufacturers don't disclose this in their literature. Most folks just go on thinking the mod has given them great mileage.

Please get back to us with your results. Some folks reported the DIC mileage was still accurate with a module installed. If one can do it, they all can. There's no reason to not have the DIC calibrated, if it's possible. In either case, we should either have a calibrated DIC, or a formula to determine actual mileage from the DIC info.

Gimme a couple of weeks. I'll reset the DIC at the next fill up and compare.
You've got me worried now.
K

DRINKDIESEL
06-01-2006, 11:18
The reason I asked, is when using a power adder, the DIC tends to become quite optimistic. Usually, a very disapointing reality is discovered once the mileage is calculated manually. This inaccuracy is normal and consistent with the operation of the module/programmer. Problem is, the manufacturers don't disclose this in their literature. Most folks just go on thinking the mod has given them great mileage.

Please get back to us with your results. Some folks reported the DIC mileage was still accurate with a module installed. If one can do it, they all can. There's no reason to not have the DIC calibrated, if it's possible. In either case, we should either have a calibrated DIC, or a formula to determine actual mileage from the DIC info.
Sorry it took so long to get back to you. Things are hoppin' at the shop here.
Here's the results of the DIC to actual.
513.8 miles-crappy single lane small town type
102.0 litres which equals 27.01 US gallons
19.02 MPG Calculated
19.4 MPG on DIC
A slight difference between DIC and actual, but not much.
I ran on level 1 (mileage) most of the time with the A2. I'll see what the DIC says when I pull my 27' 5th wheel with 5 guys and all their gear to the IHRA Canadian Nationals this weekend.
K

DmaxMaverick
06-01-2006, 11:34
Thanks for the comeback.

I don't consider less than 1/2 MPG outside of the normal variation, with or without mod's. If you are in fact getting accurate mileage displayed by your DIC, we need to find out why. Like I said, if it can be had by one, it can be had by all. It is interesting that some folks with the same truck and mod, get different results, in regards to the DIC.

What other upgrades do you have on your truck? Tire size, etc.

JohnC
06-01-2006, 12:32
Like I said, if it can be had by one, it can be had by all. It is interesting that some folks with the same truck and mod, get different results, in regards to the DIC.

I'd expect it has to do with how far from optimal the injector flow rates are. The PCM only knows how much it is commanding, not how much is actually delivered.

My DIC mileage is always within 1 or 2 tenths of calculated mileage. Same for fuel used.

DmaxMaverick
06-01-2006, 12:47
I agree. However....

Under the same circumstances, some are off by several MPG, and others, like yours, only tenths. I'd like to ID where they depart from common. All things being essentially equal, the results should be equal. But, they're not.

DRINKDIESEL
06-05-2006, 11:47
Maverick
The truck is pretty much stock other than the A2 and K&N stock type air filter. I did modify the stock airbox by hole sawing a 2" hole in the lower front part of my airbox. All this seemed to do was make the turbo more audible, which is kind of cool.
The trip to the IHRA drags with about 11,000 lbs in tow and 5 guys in the cab netted 13.4 mpg on the DIC average, round trip. It was 15.1 mpg for the trip down with my trucker buddy being very gentle on the go pedal. This was with the A2 on level 2.

martanius
06-11-2006, 10:44
I got 19mpg on my 1st tank of fuel. It was almost entirely highway because we loaded up and went on a trip. Since then I have never hit 400 miles on a tank again. My dad did one time when we were headed to elpaso he managed to get 471 miles on a tank. We pulled a 29'boat all the way back from El Paso to MI and averaged 12mpg at speeds of about 79mph. When I hear people saying they get almost 20 I always assume they are not very good with thier math. :confused: I have never even tried to run a tank of fuel at 60mph... that's just nuts.

DarylB
07-06-2006, 18:10
As of 85k miles the best mileage to date is
22mpg @ 55mph for nearly a whole tank on the freeway. For every 5mph I lose about 1mpg. I've had the warn winch & guard since it was new so this rig is pretty exceptional. 16-18.5 is the norm without babying it.

imsweetdaddy
07-13-2006, 19:39
2002 GMC 3500 C/C Dually I AM GETTING 12-13MPG at 70mph on the HIGHWAY and 10mpg in town. My father has a 2001 Chevy I dentical truck and gets 15-16mpg on highway. What the heck is wrong with my truck??? I have not seen anyone anwhere get suck poor milage as me! ! ! Truck is hard to start 8-10 second range, but if I put a new filter on it it cranks just fine. But after one tank of fuel run through it, it's back to the same hard to start. SOMEONE PLEASE HELP WITH SUGGESTIONS!!! ImSweetDaddy@aol.com I need some help because the 3 dealers around here say it's the injectors, already replaced 2 times. 140k and at 190k. I have 232k now, and that's only 40k on the injectors. This surely can't be the problem. I am diesel illiterate, but I am learning fast. Could my lift pump be weak, but if it is then why is it using more fuel, if it's starving? Truck has no smoke out off tail pipe, ever! Very clean burn, no blow by, uses about 1/2 a quart of oil over about 6500 miles. PLEASE REPLY AND GIVE ME SOME SUGGESTIONS>>> I NEED THE HELP>>> WALLET IS GETTING LIGHT FROM SPENDING IT ON DIESEL! ! ! !

muncieman
07-27-2006, 17:49
I have a 2003 Chevy 2500HD crew cab with the allison and my truck has gotten 19.9 as an average for 65,000 miles. It has on several trips been in the 24 mpg rage. It is a 2 wheel drive version and bone stock.

Now if we could just get the lousy fuel companies to charge a decent price for the fuel:) :)

BozDMAX
10-20-2006, 19:46
I first noticed the difference between the DIC and my actual mileage in March '05 and have been tracking the difference since then. After throwing out some obvious outliers I ended up with 106 data points and using a least-squares/best fit methodology can pretty much estimate my actual mileage by the following formula:

Actual MPG = .86*DIC MPG + .74
R-squared (if you remember your statistics course) is .86 - not terrible given the wide range of conditions (towing vs. non-towing, hills vs. flats, changing altitudes, etc).

so, 20 MPG on the DIC would work out to about 17.9 on my slide rule (anyone else remember those?) with the actual data.

All the data is after the Banks system. No idea if the early data for the first year before the Banks was more reliable or not.

You can take the retiree away from cost analysis, but you can't take the cost analyst out of the retiree...:-)

More Power
11-07-2006, 17:14
2001 GMC 2500HD Crew cab shortbox 4x4 LB7:

1820 miles - round trip from western Montana - Las Vegas SEMA show. Each 910 mile leg took 13 hours and 20 minutes, for a 68+ mph average speed (which included fuel & convenience stops). Where possible, the truck's speedo hovered around 85 (65 through Salt Lake and in the mountains north of Salmon, ID on US-93). Calculated fuel economy for each tank ranged from 18.5-mpg to 20.2-mpg. Best tank was the last leg from Idaho Falls, ID to Missoula, MT. Just me and about 100-lbs of gear in the truck. The 265 Michelins were aired to 70-psi front and 60-psi rear. Mobil Delvac 1 synthetic in the engine. Power Service fuel treatment used at the recommended mix ratio. One tank was B5 (Sinclair station in LV). Otherwise, all tanks but one were ULSD. And.... the VanAaken module was turned off for the entire trip.

Jim

SoTxPollock
11-17-2006, 12:23
Pretty impressive running 85 averaging 68+ and 18.5 to 20+ mpg. Your truck is right in every way. I may be able to come close to that. I've made 17.2 at 92 and 22+ at 63. I could never drive 55 for a whole tank full, would probably fall asleep. I'm suprised to find out it hasn't dropped below 17.3 with juice on level 4 for a month now. I think my truck thinks its a corvette the way the engine responds, but amazing that the mileage isn't hurt much. My lifetime average for 90,000 miles is still in the high 18's. Great Truck. I've been running the exact same air pressures you have too. However I'm having to back that down now, they're showing wear on the center more than on the sides. Noticed it more on the rears, but I know why.

colt49
11-17-2006, 14:48
MPG
Mileage is constantly 22 or 23 on highway In town is20 or 21 4K miles #2 fuel Flying J Cheyene Wy.06 LBZ 4x4 Allison Reg. Cab Flow Pro Exhaust 4.5" Stainless EDM Fits

DmaxMaverick
11-17-2006, 15:29
MPG
Mileage is constantly 22 or 23 on highway In town is20 or 21 4K miles #2 fuel Flying J Cheyene Wy.06 LBZ 4x4 Allison Reg. CabFlow Pro Exhaust 4.5" Stainless EDM Fits
Those numbers are pretty impressive. Are you using any type of electronic power enhancer? Larger than OEM tires? How are you calculating your mileage? Pencil/calculator, or DIC?

colt49
11-18-2006, 04:23
This truck is mostly stock exhaust is customed synthetic fluids except motor still breakin cycle on it. Very steady driving cruise control user and slow down and vary speed for break in. Will not install any turners or air intakes, stock is totally fine. This truck will be a good one it's just something you know when you start breaking it in and the power and strength it has. This is the smoothest tranny in the world to me. It downshifts at stops and you save brake use by tons. GM makes my truck and I'm glad I bought this one. The others are nice too buy this one is my vote. Price was real nice compared to the other guys by thousands and no intrest loan was even better. I've owned the other diesels since 93 Dodge Cummins, 96 Powerstroke, and now this one. The others sold for prime bucks because of diesel and they were ok to own but nobody on this planet has this GM setup. My right foot can take this thing to 100 mph fast it's nice to have.

jay menna
12-29-2006, 17:10
i recently switched to 285/75/16 and my mileage droped almost 2mpg. is that normal. also with 285's how off is the odometer. i heard almost 5%?

SoTxPollock
06-01-2007, 11:19
JUST COMPLETED THE CALCULATIIONS.
100,278 MILES, 5,394.74 Gallons of fuel used, = 18.588 MPG average for the first 100.

I knew that Edge was going to make it drop off!!
Long live LB7's.

ickyray
06-04-2007, 22:44
The poll can be misleading, there are different axle ratios which will affect the mileage noted. I just pulled a 24 foot TT through the Rockies for 1400 miles and average 15mpg imperial. Kept to highway speeds plus 10 over, nobody was waiting for me! Truck has 3.73's and 4X4.

DmaxMaverick
06-05-2007, 00:23
The poll can be misleading, there are different axle ratios which will affect the mileage noted. I just pulled a 24 foot TT through the Rockies for 1400 miles and average 15mpg imperial. Kept to highway speeds plus 10 over, nobody was waiting for me! Truck has 3.73's and 4X4.



All Duramax equipped light trucks are available with only the 3.73. Any other ratio would have to be owner installed. The 8.1L and 6.0L gassers have the option of 3.73 or 4.10. Tire size changes will effect mileage, though. 10 over with trailer in tow, and no paper trail??

SoTxPollock
06-07-2007, 11:16
Yesterday at the station I was adding my fuel supplement and started to pump diesel and two guys walking to their truck made a comment. That won't help it will still only get 13mpg. I glanced at his truck it was a chevy gasser.
I told him I have an average of 18.58 for a 100, 000 miles now and not all of that is easy driving. I've towed some pretty heavy loads. He said oh, you got the Duramax, took a big gulp of his Coors Light and said come on Joe lets go.Got in his truck and drove off. I don't think he believed me, or else he was kicking himself for not driving a diesel.

Texas Hunter
06-19-2007, 10:58
2001 4x4 HD ext cab. 275 tires got 19 to 21 mpg. 200100 miles. Injector pump @ 25000m, water pump at 100,000m. just traded 3 weeks for a NBS GMC 6.0 gas 6-speed and traded yesterday for NBS DURAMAX.....Should have known better........but I'm old and allowed to make misteakes....

Ryan03
08-05-2007, 17:31
03 d/a 2500 reg cab , 4x4, 3.73s, 265s, 18 city stock, 23 highway stock, 16 city juiced level 2, 21-22 juiced highway level 2. Hand calculated. 70 to 75mph highway, mostly flat with some long grades here and there. Seems to get better highway mileage on the button rather than the pedal.

oneton
10-08-2007, 19:59
Long time since I last posted but after reading this thread again I had to post my recent milage record. Had to make a mad dash to WV (from FL) for the passing of my Father-in-Law just about a month ago. On the way up I didn't even bother. It was just one speed(as fast as I could get away with). But on the way back things were a little more relaxed I got 21 mpg in my 02 4x4 CrewCab dually that just turned over 160,000 miles (original injectors and bone stock). Now mind you I had nothing but the four of us and the luggage in the truck but it's wasn't too shabby for a 7000# tank. LOL







David
__________________

Philsauto
01-23-2008, 21:32
I added a Bully Dog downloader and set it on the 1 power level on the way to Phoenix from my home in Hemet. I ran 70-75 mph and got 18.5mpg. On the return trip, I changed the power level to 2. I got 21 mpg on that trip and 22 mpg on a subsequent trip, though I ran that one at around 65 mph. I was pleasantly surprised by this.

pimajim
02-01-2008, 09:17
With 100K on my 2001 Duramax I have averaged 20mpg
with no load, 15MPG with a 3000 lb truck camper, 10MPg with
a 33 FT 5th wheel trailer. Interesting, recently I got new Cooper Tires, replaced my old Michelin's, Coopers lowered my mileage to 19???
This is a stock truck except for the L&N air filter. Most of our driving is rural mountain areas.

2500HDTalley
03-16-2008, 22:39
I was getting 13 average. Did some research as I had a problem the dealer mech's couldn't find. Lead them to the fuel injector area and they found my injector pump had gone bad. Once this was fixed I got 18 average. Dropped from 15w-40 synthetic to 5w-30 synthetic for the winter and am now getting 19.5 average.

Idahobidcaller
03-26-2008, 13:23
I have been getting 16-18 around town and 20 highway on my '01.

reparkerjr
07-08-2008, 10:36
Mileage is greatly affected by driving conditions. I get 16-18 mpg driving in town stop and go. On the highway I get 20-23 mpg depending on speed. My best was towing a 6 ft utility trailer at ~ 50-55 mph descending from 8000 to 6000 feet in 200 miles; I got 23.2 mpg. Typical is 21-22 mpg at 60 mph decreasing to 19+ mpg at 70 mph.

reparkerjr

npauli
08-08-2008, 09:49
I just bought my first diesel (see sig). The first full tank I ran was maybe 1/3 on the highway at 60, 1/3 in town, and 1/3 interstate at 70. I got 20.5 mpg!!!

I'm thrilled with my LB7, especially since the miles/dollar work out to be only about 10% worse than my gas truck, despite being 3' longer, a bit taller, 4wd, and a good ton heavier.

Fightfan
11-16-2008, 17:46
I've owned a few trucks for my remodeling company. I had a 97 GMC 1500 Z71, an 88 chevy 1500 extended cab LB, a 92 GMC 3500 Vandura with 6.2L N/A, and my 01 Silverado. Hands down the two diesels were much better all the way around. I could easily get 450+ miles out of my van on the highway. I've just done the upgrades to my Silverado, so I don't know what the mileage is yet after the fact. Bottom line: WOOOHOOO for Clackers!

JDiesel03
08-25-2009, 19:20
My 2003 LB7 (3500 4x4 dually)with breathing enhancements(ram air and 4in exhaust) just did 2500 mile mostly freeway trip largely on cruise at 75mph for overall round trip average of 19.6mpg. Lightly loaded with about 1500# of gear in the bed. My mileage starts dropping rapidly at over 65mph....trips holding to 65mph have netted me typically about 24mpg. Love it!:D

NeilLB7
09-11-2009, 07:42
On a totally stock 2002 HD2500 Allison Ext Cab 4x4, all hand calculations, purchasing from the same station and pump, filling from 1/4 tank each time, using Stanadyne PF each fill up...I've come up with the following over the last 11 months.

Highest 18.85 MPG.
Lowest 16.90 MPG (I did alot of city driving this go-round and was a little heavy on the pedal at times)
Furthest Distance from 4/4 to 1/4 tank (fill up point) = 392 miles (I do not go below 1/4 tank as a personal preference)
19.878 gallons average purchased at fill up.
Total overall average MPG = 18.01
Average price per gallon = $2.629/gallon
Total miles represented to produce this data in 11 months = 13,233 MI

The truck has 142,000 miles on odometer, no modifications at all, original injectors, Mobil Delvac 1300, Mobil Syn gear lubes, Valvoline Dexron III ATF, Mobil1 5W-30 transfer case lube, OEM Bridgestone tires etc etc. About a 60/40 ratio of hwy vs. city driving. All empty miles, no towing. 65 MPH highway shows about 18-1900 RPM.

So...unless new injectors and such would really improve MPG's...I don't see how people get anything significant over 20 MPG Avg. My friends claim to...but they have zero data to support the claims.

Now keep in mind this is all average MPG's for me. Which is all I pay attention to. Because I'm buying diesel when my average driving empties the tank.

npauli
09-13-2009, 19:33
So...unless new injectors and such would really improve MPG's...I don't see how people get anything significant over 20 MPG Avg. My friends claim to...but they have zero data to support the claims.

It can be done, but not without really working at it.

I've got data over 15k miles with quite a few numbers over 20 (details below). The biggest difference is:
1) the manual tranny gets great efficiency to start with, and enables lots of special techniques to save fuel (like engine braking or the ability to coast in gear for zero fuel use or with the clutch in for minimal driveline drag).
2) I've been paying particular attention to driving for best fuel economy. It takes me longer to get where I'm going, but I burn less fuel on the way. If you saw me drive, you'd probably find the numbers below more believable.

15,697 miles (adding 3% to odo for 265 tires)
699.5 gal (from the pump)
22.4 mpg average
26.2 mpg = best tank
18.5 mpg = worst tank (never got above freezing, some cold starts ~ 0F)
12 months

I got just over 20mpg when I bought the truck in july 2008 (previous owner did too). I probably got 1-2 mpg more from using all synthetic fluids, and the rest is driving techniques.

NeilLB7
09-14-2009, 05:45
I would say that a regular cab manual truck could get better numbers than myself...and things of that nature. Thats understandable. Or even some tunes that are designed to increase economy will help. But I've got people with larger trucks, huge tires, no gearing changes, tuners, etc etc that tell some pretty good tales on fuel mileage.

I'd say that some instantaneous MPG's in my truck are really good considering my average. But again, I can't go by that because I dont drive like that 100% of the time.

My friend likes to brag about what the computer tells him at 60mph on the highway...as if thats the average he gets all the time. Yet I tell him that his worst MPG he see's on it is just as valid as the high MPG he sees. When he brags about getting 24MPG...I say he actually only gets 12MPG by the same method. His low is just as valid as the high to me.

We argue, he mumbles something, and we start talking about something else usually. :D

guss
11-12-2009, 16:24
I have a diablo program
k&n
4 exhaust on the 85 hp setting i can get between 18 to 20 on winter fuel
and as high as 24 in the summer going easy on the throttle

captcnduit
11-17-2009, 17:55
I have a 2002 2500HD. Bully Dog Power Pup programmer set the extreme setting. I opened up the stock air box, tire pressure at 85psi in 245's.

In 2008, took a 500 mile trip over Thanksgiving. I drove 60mph both ways.....and yes it was horrible but wanted to see what mileage I could get running that speed.

I averaged 25.5 over the 1000 mile trip.

AND I WILL NEVER DO THAT AGAIN....HA HA!

BigBlockTank
11-27-2009, 16:50
I get about 16-17 MPG on my 6.6 DuraMax with 9850 mi.

pamax
12-03-2009, 20:28
I have been getting 17 to 19 mpg with 81,583 miles on my 01 crew cab.

Centurion6R
01-27-2010, 12:39
i've been getting around 18-20mpg with my 01 in roughly -20 degree weather...pretty darned good.

DBradley
03-17-2011, 04:07
I am a new diesel owner, bought a 2001 GMC K3500 Dually. I have added PPE programmer, S & B cold air kit, and 4" silverline turbo back exhaust. The truck just rolled 100,000 miles on it. I also use Stanadyne performance fuel additive. My mileage increased to around 17 or 18, now all of a sudden can't seem to get any better than 15. Any ideas?

Driveshaft
04-19-2011, 11:56
I Got My Problem Solved And Now Am Able To Login. Thanks.

ricksofla
04-26-2011, 16:16
2005 Ford E250 van 5.4 liter, 85,000 miles, 11/12 mpg, 2002 Chev. 3500 LT crew cab, 4x4 dually, 317000 miles - 17 / 18 mpg. priceless!!!

Dustdevil1
02-26-2013, 16:22
I often pull a trailer weighing around 10k lbs. Under those conditions, I typically see 10mpg while climbing from sea level to the Mojave Desert (around 2800 ft). 16 mpg on the way home. 13 mpg on flat freeway.

Without the trailer, I see about 16 combined, and about 21 on the highway. But I usually drive past 70 mph. Fuel mileage varies dramatically with rpm on my truck. I would imagine it does with all of them. I have 3.73:1 axles, and it's a 4X4 with oversized tires. I'm sure that has a little something to do with it. Plus, I don't often specifically drive for fuel mileage.

Dek Hawkins
09-19-2015, 03:28
I have a 2500 HD DMAX, 2002, and drive it in England.
I can say it does 27mpg on a 100 mile motorway trip @ 70-80mph,
or 22mpg dodging around.
I know many 4x4 owners who get less from their 2.0L diesels.
I would never swap it. I want a fifth wheel camper to haul, but need to get one from States ??

Ian7
11-25-2015, 18:19
I have a 2500 HD DMAX, 2002, ... it does 27mpg on a 100 mile motorway trip @ 70-80mph,

Given how far from 'typical' that number is, may I ask if that was a single 100 mile trip and tank top-up when you got there? I guess what I'm saying is that the top-up may have shut off very early and given a false economy?

or maybe a 100 mile long downhill stretch? :-)

(yes I know imperial vs US gallon, still 24+ in our context)

chessy56
01-19-2016, 14:50
Without a head wind, running ~57-60mph, mostly empty bed, I'm doing about 22-23 mpg on the highway. Depending on the severity of the head wind, I'm around 19 highway. Most trips are WI to mid IN.

Currently, I'm not getting Chit- truck appears to be down with head gasket issue. 400,700 on the odometer. Sure would like to upgrade to something newer, but a drop in fuel mileage would blow....

What's funny is watching the 50 mile average fuel economy with my Edge monitor plugged into the diagnostic port. Going through Chicago (I-94/I-294 with the sound barriers/trees/buildings blocking most wind), the Edge reported as much as 50 mpg! Bite me! Calculated value and not real, I realize. Still amuzing to watch.