LBZ Fuel Mileage [Archive] - TheDieselPage.com Forums

Brad Pelot

03-13-2006, 11:34

Just got back from a dirt biking trip. pulling a 6 x 12 enclosed with 4 bikes, gear, tool chest, etc. probably around 3000 pounds. Got an average of 12.2 going 82 mph. This is adjusted for odometer error. Not as good as I had hoped but we were going fast in a lifted pickup. The other truck was an lb7 with the almost identical load, he got just over 13 but he was going around 85 to 86 mph.

soot

03-13-2006, 23:21

My LBZ mpgs are slowly improving. With around 1400 miles on it, I got 17.92 hand calc'ed on a 300+ mile trip into Michigan last Friday running 72-77 mph. No problems whatsoever with mine so far & I like it better than my old LB7.

mark45678

03-14-2006, 16:17

5000 mile on it now ... average is just 16.6 mpg on winter blend fuel and its a crew cab 4x4 with a cap , 70 % high way driveing and speeds around 80 mph. It seams like its getting about 1 mpg better then my lly. I will say it has no problem running at 80 where the lly seamed to streach a bit to get to 80. The 2006 allison is the best tuned trans since they started using them in 2001!

Tsckey

03-18-2006, 05:51

A friend with a new LBZ came up for a visit from Southern CA couple days ago. He just sent me a note to tell me he got 20 mpg on the return trip cruising at 75. I made the same trip in my LB7 a few weeks ago and got 19.26 on the same route at the same speed. I guess that 6th gear helps.

TC

Mr. D

03-18-2006, 10:02

Tsckey

03-18-2006, 17:41

Well! We here it from the man himself! Welcome aboard amigo.

TC

spongebob

03-28-2006, 19:10

i only have 5500 miles on mine. and i have a ladder rack on with ladders hanging in the wind, 3 tool boxes bolted to the sides and a full load of freon and heavy tools and supplys..my last tank got me 17.0 mph..i travel at 75mph when on the highway..Oh yea im happier than a pig in $hit...my ole dually 454 got 6mph..

tonyskidoo

03-31-2006, 05:13

I only have 350 miles on my LBZ and I am getting 13.6, it is a CC 3500 Duelly so I cant complain. But with all the high numbers I am seeing from the other posters I cant wait to see what kind of mpg I am going to get.
Tony

Texas Bulldog

04-09-2006, 18:56

I have a little over 800 miles and my first tank by computer was 14.9mpg and by calculator it was 15.5, second tank 15.2 by computer and 15.6 by calculator.

BurnsK

04-18-2006, 14:41

I have 4000 miles with a stock CC dually. It gets better every tankful. My '04 seemed to get just a little bit better (identical truck) but this sure cruises better at high speed. Love the 6th gear. By the way, figure the milage by hand, it actually comes out better than the computer. The computer figures it burned 30 - 32 gallons for an approximate milage of 16 but it only will take 28 - 30 for a milage closer to 17 - 18 mpg. The computer figures it burned more than it actually did.

kenny

04-19-2006, 09:26

hey guys i got a bone stock lbz (I LOVE IT!!!) im getting about 17
mpg' s city and about 20-21 highway, i just put my goose neck hitch and brake box in it this last weekend ( a b&w turnover ball and a techonisha pilot)
a lot of people say it takes years to get your oney back for the cost of a diesel but in my opioin it is wirth it whenever i need the power to poull a hill with a 4000# tractor on the flat bed, try to do that with a 6.o then tell me how long you think it will take it to be worth it!!

Matt Robbins

04-24-2006, 19:20

My mileage is starting to go up a little. About 16 mpg on the highway according to the computer, about 17 when I calculate it. I've got about 5,500 miles on it so far, I put a set of 295 BFG AT's on it right after I bought it. I only ran two tanks of fuel before I swapped the tires and can't really see that it made a difference in my mileage.

Crew Cab 4x4 SLT - DMAX - Love it.

hapaschold

05-08-2006, 17:29

1st tank was showing 17.1 as long as i kept her at 70 mph. 75 would drop to 16....

hopefully once broken in, 17 will be norm at 75-80

Dave

05-24-2006, 15:34

Well, my truck just hit 1000 miles. I have been getting 14 or so combined averge. However on the interstate at 75 for a full tanK it was only 13.7 mpg. I hope it goes up at the others did when they broke in.

I hope when I get back from this hitch on the rig to hook a 12000 pound load to it and put some miles on it that way.

Rippin

06-14-2006, 09:30

1st post here. About 2k miles in the first month. Overall average so far is 15.2. Driving is a even mix of rural driving nice and 75-90mph highway. Last tank was 15.6 with a higher percentage of 80-90mph highway. I put 285 tires on and the mileage is with calculated with corrected odometer based on GPS, so fairly accurate.

So far very happy. First GM product in a while, replaces a 2000 f350 PSD which was a great truck also. Getting 1-2mpg better than the PSD and that is with a tight engine still hope to see another 1mpg when I get closer to 10k mileage.

don

j7l2

06-14-2006, 10:49

I have a 2006 LBZ in a GMC, crew cab, shortbed, 4wd, Allision trans. Bought new in April 2006. I have recored the following mileage:
Tank #1, actual 18.6, DIC says 16.9
Tank #2, actual 19.6, DIC says 17.5
Tank #3, actual 19.8, DIC says 17.6
Tank #4, actual 18.9, DIC says 17.3
Tank #5, actual 18.9, DIC says 17.4

All driving is combination city and highway with AC on, highway speed 65 mph. Truck is 100% stock. Using Stanadyne Performance additive in every tank, 6 oz.

I have asked my Dealer if the DIC is always inaccurate, he says they have found that it varies in every vehicle, some are correct, some are low and some are high on the mileage calculation. I have asked them to contact GM about it. I would think that there must be a calibration adjustment somewhere. If not then the DIC info is of little value in my opinion.

Your comments,
JimO

MillCreekDMAX

06-30-2006, 06:57

I have 3400 ish miles on my GMC 2500hd cc allison 4wd.

I have been getting around 15 mpg combined. I havent been using any addatives though. that might help my mpg in the future.

tsitts

07-02-2006, 19:43

Just traded my 04 2500HD LLY 38000 miles on a new 06 3500 LBZ Dually, drove from Denver to KC to drop off old truck and pick up new. 80 mph the whole way 570 miles.

Outbound trip in LLY 16.9 mpg overall
Return trip in LBZ 11-12 mpg for the first 300 miles, 15.3 mpg in the last 270.

Next day 100 miles of local driving 600 miles on odometer 55-65 mph, 15.9.

LLY 5 speed allison 80 mph, 2400 rpm
LBZ 6 speed allison 80 mph, 2050 rpm

Looking good to beat 04 mpg once fully broken in.

Prestonia24

07-08-2006, 21:46

First Post Here, let me say I thought I knew a lot about diesels before i bought one lol, (I drive a 2005 Ford E350 Ambulance w/ a PowerStroke Diesel about 2,000 miles a month). Definately knew that i didn't want to drive a Ford Truck (Never have liked them, their diesels don't impress me much)
- but there's always room to learn a bit more, and these forums are filled with information from Diesel owners.

I'm 21 Years old and work as an EMT for a local ambulance company here in SoCal, and just recently purchased a 2006 Chevy Silverado 2500HD w/ the LBZ Duramax 6.6L Diesel, and i'm quite impressed. I'm dwindling down the last quarter of the first tank (the tank the dealer purchased lol) and the DIC is saying i'm only getting 13.5mpg, but hey, i know that the mpg will get better as it gets 'broken in'. My 01 Sierra got 14mpg and i have much more truck than before.

The 6th gear on the new Allison tranny is wonderful, i can cruise down the freeway at 75-80 no sweat, and the acceleration is terrific for a diesel (at the cost of fuel economy, but w/e).

I purchased the truck because i wanted a larger cab and 4x4 capability, for when i go skiing in the winter (my old 2wd w/ snow chains didn't cut the mustard, even for California mountain driving).

I met many Duramax owners before i purchased one myself, and they all told me how wonderful their experience had been with their GM truck.

Plan to put some larger/wider tires and when the Banks aftermarket kits come out for the LBZ Diesels, i'm thinking about changing the exhaust and some aftermarket guages as well.... After all, 360 HP is 'sufficient' at this point, but who knows, i might want 'more' lol....

hapaschold

07-09-2006, 04:00

D-MAX

07-18-2006, 19:26

I have 890 Miles so far and am geting 18.8 mpg, better than my 02 Duramax at the same miles, and my 02 at 58000mi was getting 20 to 21 mpg with a best of 22.6 mpg at 65mph so I hope my 06 will do as good or better!!

jevanb

07-20-2006, 03:09

filled up yesterday after first tank after dealer, 636miles total, tank was topoff, ran 377miles @ 18.17gals=20.7mpg, truck said i used 20.7gals total=18.2.
I run 56 miles, mostly hwy miles to and from work @70mph about 15 city to get out @ 35mph. A lot better them my 04 cc 4x HD 6.0

nailem

07-21-2006, 08:43

im thinking of buying the new LBZ and all this info has been great. i was woundering what gear ratio you guys had. i heard it makes a big differance in the mpg. im not looking to do any heavy hauling so the 3.42 would work for me. what do you all have?
thanks

jevanb

07-21-2006, 12:30

373 is all you can get unless u get the 3500. with the 6speed it is geared final to act like a 342

JohnC

07-21-2006, 14:34

Yeah, the new 6 speed Allison has a double OD too. Can't immagine going any longer, unless you spent all day cruising unloaded at 100 mph...

cowboywildbill

07-26-2006, 04:43

We just picked our 06 D/A 3500 4X4 C/C. It had 28 miles on it. I only drove it about 9 miles and dropped it off at an RV dealer to get a B&W gooseneck hitch installed. The fuel mpg computer said it was getting 9.7 mpg average.
I sure hope that the computer isn't accurate. We were getting an honest 15.8 from our 02 "same model truck" just running around town and not babying it. And 10-13.2 mpg towing. I will have to run a tank of fuel thru the 06 and do the math.

JohnC

07-26-2006, 08:27

It had 28 miles on it. I only drove it about 9 miles ... The fuel mpg computer said it was getting 9.7 mpg average.

Did you reset it before getting the 9.7 mpg reading? If not, it's factoring in the first 28 miles, where it probably never went faster than 15 mph...

caddy527

07-26-2006, 19:07

I have less than 700 miles on my Sierra crew LB SLT and I'm getting 14.8 around town according to the computer. I gassed up, reset my fuel meters and was on the highway for about 15 miles and the AVG meter read 16.8. I'm expecting great things form this truck and good milage is just the beginning.

cowboywildbill

07-28-2006, 06:35

We just traded our 02 in for an 06 D/A C/C 4X4 Dually. At first the computer said we were getting 9.4. But then we topped it off and I drove about 250 miles. I topped off again and did the math. I was getting 15.9, this was in town stop and go. The computer was saying 14.8. I think it is a little under the real milage. I was getting about 15.5 to 16 running around,and driving hard also in our 02 GMC. I think the new one will do a little better once it gets broke in.

rtigert

07-31-2006, 22:55

Picked up the truck in Joplin, Missouri 404 mile trip home. Accelerated/decelerated probably 200 times during the trip, never on cruise, continuously loading and coasting the engine. Averaged 72 mph, DIC said 16.1mpg, hand calculated 17.65mpg. I couldn't be happier at this point!

EdHale

08-02-2006, 14:43

I picked up my new LBZ on 7-5-06. It is a GMC CC SB and is bone stock including stock tires. Here is my mileage so far. Some of these fillups are towing a 4,500 lb boat and trailer, some with a 900 lb empty boat trailer and some with no trailer. The 19.5 mpg was with no trailer and 75 mph over 250 miles. The rest is a mixture of highway at 75 mph and 2.5 miles a day to work each way (not helping at all).

Total truck miles MPG
244 18.5 no trailer
478 15.0 4,500 boat
806 15.5 4,500 boat
1,185 19.5 no trailer
1,512 17.5 no trailer
1,783 15.6 no trailer 6,500 boat for 10 miles
2,066 17.8 empty boat trailer
2,306 16.8 empty boat trailer

I have to say the 16.8 was partially due to entering the interstate, with the empty trailer, and a "youngster" in a souped up Honda Accord (you know the one with the big oversized muffler that sounds mean!!!!) attempted to pass me while I was still in the acceleration lane. I just couldn't stand it and when he got up beside me, making a lot of exhaust noise, I punched it and left him with a silly grin on his face. By the time I was at 75 mph I just punched cruise and he never ever came up on me for the rest of my trip until I got off of the highway. This LBZ is a big step up from my '98 6.5. Smiling..............Ed

caddy527

08-18-2006, 16:04

I just turned 2000 miles and got 18 mpg on the last tank. No highway but some 50mph stretches. I put in Amsoil at 1600 engine and rear. Before that I was in the 16 - 17 range. Don't know if it's the oil or the truck breaking in but I'm not complaining.

FBJR

08-18-2006, 20:11

I have noticed the DIC is about 1 MPG under too. Getting about 15.8 on the first tank.

Makes me wonder how far off the speedo is to start?

Just got the Diablo and did the 65 HP tune with corrected tire dia of 33 inches. On the freeway it said I was going 40 :confused: when it was really about 65. Then got a brake warning for gosh sakes!!

But I could really feel the diff :D

Going to reset tonite using tire size vs dia and see if it takes and the code goes away.

FB

EdHale

08-20-2006, 13:19

I just got home after a 500 mile weekend trip. The first half of the trip was all highway at 75 mph, removed a 7000 lb boat from the water and towed it 2 miles to a gas station for fuel, then two miles back to the launch. The rest of the trip was at 70 mph home. averaged 19.0 mpg for the entire trip. Total miles on my 06 LBZ right now is 3,300. Ed

No towing except for the 4 miles with the boat.

cowboywildbill

08-21-2006, 06:39

Filled up and did a short empty non-towing " semi Highway trip" Some stop and go on a four lane Highway a few lights toward the end. About 135 miles round trip, the computer said we were getting 19.4 at one point. It mostly was saying average of 17.4 while we were at 55 to 65 mph. It seems to be getting better and we only have 1300 miles on it so far.I did an oil and filter change at 1,000 miles Rotella 15w40. I will go with synthetic Rotella after a few more oil changes. I'll post again after I do the math on the last trip. I think maybe about a 16 mpg overall so far best guess.

Docklobster

08-21-2006, 15:45

Just returned from my first 1000 mile trip. 1500 miles on the engine now. Ran the AC the entire way, truck is stock. DIC read 11.2 MPG towing my loaded trailer ~9000lbs. Basically southern CA over the grapevine to monterey and back, AVG speed 55 to 60mph.

The MPG did drop a little when I smacked a cow returning over the grapevine!! :eek: Truck didn't get a scratch but the trailer has some damage. Cow didn't fare too well, but I was the second person to hit him... Shocks bottomed out but I don't "think" anything was damaged we hit hard, I'm going to the dealer this week to double check everything...

soot

08-22-2006, 21:41

I'm starting to think that you need to get 25k+ miles on a Duramax to get consistantly good fuel economy (my '04 LB7 was the same). I was stuck in that 18.5 to 19.2 range for a long time (this is on long Interstate drives), but this past week, I've been getting 20+ mpg with ~26k on my LBZ. Monday I got 20.42 mpg & today I got 20.07, both 300+ mile trips at 70+ mph, hand calculated & using my GPS to track total miles.

Not that I wasn't impressed before, but I'm REALLY starting to like this truck.

cowboywildbill

08-23-2006, 10:02

Just did the math after our little trip, we had some stop and go Ranch errand type stuff and a little idle time. The average was 15.9 mpg. Still only 1400 miles on truck. We are happy so far.

Barkbuster

08-27-2006, 17:56

Just got my new truck this month and still have not taken a trip in it yet. 800 miles on it so far and never let it drop below 1/2 a tank yet. can`t wait to tow something with it. mileage has been good 17.2 1st fill 1/2 tank. and this tank was just over 1/4 ---17.6 mostly 5o mile round trip to work and showing it off to friends love the power l8r bb

cowboywildbill

08-28-2006, 03:55

Congrats on your new truck. You should be happy with it when you tow, they pull really strong. Those extra two tires on the back of our truck do knock our mpg down 3 to 5 less mpg overall. I'm guessing, but it seems like the 2500 gets 3 to 5 better than the 3500 does, from what I read on the forum.

Barkbuster

09-02-2006, 15:37

After another 220 miles in a week 17.1mpg. 2 days at the dealer for fixing the chirping fan belt (who knows how much idling they did?) and 3days to work with some running around on the weekend. 970 miles on it now and the chirp is back

Mr. D

09-03-2006, 23:24

22 MPG on highway, 14 MPG pulling a 23' travel trailer! These were the best fill up mileages on a 1800 mile trip through the California Sierra and Nevada desert.

Barkbuster

09-10-2006, 09:58

18mpg last tank. 1/2 hr added to the hr meter while at the dealer for a new belt and pulley adjustment. its getting better! This may give me 20 if I ever get her broke in.

farmerpatrick

09-27-2006, 16:23

2500 HD 4WD.. extended cab. allison. all power . getting 14.2 on hwy. 9000 miles. Just bought truck. What's wrong with mine? No lead foot here.

FBJR

09-27-2006, 19:08

Just passed 200 miles and getting about 17 mpg mixed driving.

Got 22 coming home from Reno on Sunday :D

FB

BigHerb

09-28-2006, 07:58

I just got my new 2500HD CC LT3 4x4 day before yesterday (09/26/06). I had to drive to a new contract site, about 300 or so miles, and got 16.49 MPG hand calculated. That is a great improvement over my 2003 Silverado SS that got 12 - 13 with the 6.0 HO. This new truck is great!

KrazyNate

10-06-2006, 14:18

Mine is an 02 2500HD. I just filled up, 22 gal on the nub and only 289 miles... I figure about 13.2 MPG... I fear the dreaded injector issue.... :(

EdHale

10-08-2006, 18:04

I just got back home after a 500 mile trip, not towing and with the a/c off. I manged to keep it at 65mph the entire trip and 99% of this trip was on limited access highways with the cruise on. I have a '06 CC LBZ and it turned over 6,000 miles this trip. Overall economy 22 mpg. I have made this trip before with the a/c on and it drops to 20 mpg. I'm happy. Ed

RETLAW

10-09-2006, 17:10

My fuel mileage so far, 900 miles on truck, about 15.5 around town with some highway. All 2 lane highway yesterday, 55-60 MPH, with a few small towns, 320 miles, average was 20.6 MPG. This is with calculator, dash showed only 18.5. I did both fillups, one at start and one at end, and made sure it was really full at end. I was happy. This is just a little better than my 02 was getting after 75k.

2007 Silverado Classic D/A C/C LT short box, 2wd

2002 Silverado D/A ext cab LT short box, 2wd. MUST SELL!! (see classified)

RETLAW

Prestonia24

10-09-2006, 23:44

I have an 06 LBZ CC SB, and have been seeing anywhere from 14mpg (all streets mostly), to about 18 on the highway.

I've not been on any long trips (+50miles ea way) to test out to see if I can get 20mpg on the highway (at 67mph).

I've been making a table of a bunch of information so that when I hit the magic break-in number I can see the fuel economy change.

Thus far, almost 3400 miles in, i'm still seeing about 15.

http://img147.imageshack.us/img147/5035/fueltablepb8.jpg

ohsnow

10-11-2006, 05:49

Had mine since Auguast 16 2006, city as low as 12.6 hwy 21.2 hand calculated.

Total life average is 16.279 hand calculated from new.

Very happy tus far. Present mileage is 3500 and MPG climbs every tank.

Best runs are on hwy 401 to Toronto at 75 mph.

Barkbuster

10-15-2006, 15:10

Last tank got 18mpg just 3 weeks of back and forth to work. 2000mi. on it now.
No steady highway driving yet. Was hoping for 20mpg going to work so a little disappointed for now. At the rate I`m going it may be a year before its fully broke in, but it is improving.

Londell

10-19-2006, 21:59

I have 2006 LBZ with 13K miles and get consistently 17mpg in city and 23-25mpg on freeway. My optimal mpg on freeway is at 55mph and get 25mph, but I cant stand driving that slow and at 60mph get 23mph and at 65mph get 21mpg and I dont go over that because I'd rather take my time and get better fuel economy. When towing 14,000 lb Fiver I get 12-13mpg on the flats and 10mpg on grades all at 55mph to 60mph. Not bad.... but I noticed when I took my truck into the dealer for the glow plug recall they also reflashed the emissions control and I had a significant drop in mpg...city was 13-15mpg and highway was 17-19mpg....it took about 5k miles for it to break back in... so I suggest when you take your truck back for dealer recalls make sure they do not reflash your emissions computer if at all possible. Just my opinion.

upsguy

10-22-2006, 00:36

I've had my '06 LBZ for almost 2 months and I used to get 19-20 highway doing 70 mph and 22-23 doing 55 mph and then ULSD hit and I'm getting 2.5-3 mpg less.

Barkbuster

10-22-2006, 18:39

Topped off today after a short trip and a day to work and back not even a quarter tank but the bit of cruising I did @65mph helped 18.9 mpg.

FBJR

11-06-2006, 22:56

Got 21 MPG going from Vacaville to Monterey last weekend.

CC SB, 33 inch tires, Camper shell, Diablo 65hp, 4 inch cat back.

Cruise control set at 75 mph :D

I have also had several 18-19 tanks. Love the truck :)

up@12

11-07-2006, 05:24

I have 35,000km on my 06 duramax and am getting 17-18 mpg but was getting alot better when I first got the truck. I think I need to beat on it for a bit. LOLOL

Barkbuster

11-07-2006, 11:23

Took a 460 mile trip with my dirtbike in the back @65-70mph 18.8mpg. 3500 on the truck now. Usld may be hurting it a bit. really bummed it didn`t get over 20 on this trip

up@12

11-08-2006, 04:47

I have 35,000km on my 06 duramax and am getting 17-18 mpg but was getting alot better when I first got the truck. I think I need to beat on it for a bit. LOLOL

Sorry I am getting 14.6 MPG I typed the wrong thing. But in saying that last night I took out my AFE filter and put in my stock filter and with the AFE filter I was getting about 122km to a quarter tank now with the stock filter I have 122 km and it has just moved off the full mark. Anyone else ever have this?

Barkbuster

11-10-2006, 12:30

Best week yet! 19.3 no highway just to work and back

Zacc

11-23-2006, 23:18

Does anybody know what the gas engines get for mpg? With diesel costing over 50 cents more per gallon it's tempting to look to the underpowered option.

DZ

Barkbuster

11-27-2006, 11:07

I got to try a hybred GMC while mine was in for service and used it to go to work for a day. I reset the dic and got 20mpg to work but coming home dropped the average to 18.3. Had the 5.3 with electric assist and was not bad. peppy performance but not as much power as the diesel. Was weird when the motor just shut off at traffic lights. As soon as the brake was released it was running again. the diesel is also less noisy.

Lawrence

12-02-2006, 15:53

Just breaking in my 2007. 330 miles on it now. Filled the tank at the half-way mark. In mixed driving and during break-in I averaged 15.8 mpg. A little less than I'd hoped for, but I am sure it will improve as things get seated. :)

Can't wait to see how it pulls our toyhauler!

8lug

12-05-2006, 17:50

Boston to Auburn, Me. 225 mile round trip. 70-80 mph dic says 17.5mpg. i got 2200 miles on my truck so far. 07 gmc cc longbox stock. When i drive in bumper to bumper traffic all week it get 14.50

Barkbuster

12-09-2006, 14:54

Temps took a plunge around here this week and so did my milage! 15.7 driving in 0 to 20 degree temps last week. The warm-up idling I did while putting the tractor away as I finished work hurt the milage more than the cold I suspect and I won`t be doing much more of that anymore,

JohnC

12-12-2006, 16:28

Temps took a plunge around here this week and so did my milage!

Our distributor started delivering 20% winter mix last week....

Barkbuster

01-07-2007, 21:14

Haven`t used the truck much since the cold snap last month. I checked tire presures before xmas and all were around 45psi. I reset to 60psi front and 50psi rear and the ride got a little stiffer but the milage got much better! 19.1mpg, my 2nd best tank so far.

Kennedy

01-08-2007, 11:27

I need to check my tire psi also. Glad you mentioned it!

My 07 wants to run at upper 15's at 72mph and upper 17's at 62 mph. I have been playing with ECM tuning and had it running at 20-21+, but the short hops, varied conditions, and warm ups knock me back down opn average. It is definitely encouraging and I see definite gains from tuning, I just need to collect more data and refine the tuning a bit more. DIC appears to be dead nuts on so long as I stay away from the pulse width tables.

The truck only has a few hundred miles on it so far and I need to get my usual SS cold front for it soon.

SoTxPollock

01-08-2007, 12:27

John, do I understand correctly that your EFI Live works with the 07? I thought they were 32 bit processors instead of 16.

the_croz

01-10-2007, 00:18

2006 3500 WT, 1LT, Chassis Cab. 161.5" wheel base, 84" cab to axle, LBZ W/ 6sp Alison, 3.73:1 gears, 215-85-16 with less then 3,000 miles on the clock.
I just took a 300 mile ride @ 75 mph.. got 12.8 mpg and @ 80 mph got 12.6 mp. I'm happy..

Sea-Air-Ahh-LBZ

01-14-2007, 20:21

I am new here only one tank of #2 through the 07 GMC Sierra 2500HD ext cab LBZ motor. All fwy. Buena Park up Cajon Pass to Victorville back to Laguna Niguel. 16mpg DIC 17.5mpg caculated at fillup. avg. speed 70-75. I'm like-n-it !

mschuyler

01-23-2007, 12:13

My son in law reported over 21 mpg on a road trip up I-5 from San Diego to Seattle. That's about a 1400 mile run. Crew Cab 4wd long box.

DieselMonk

02-13-2007, 05:49

First time I ran a whole tank of fuel through my 07 Classic, Crew cab, long box. Short distances only (nothing over 10km on the highway) lots of cold starts, winter front off and I got 18L/100 on the DIC, but 16.9L/100km hand calculated. I used to do same route with my old truck and a 6.0L gasser and averaged 22.5L/100km. That is 5.6L/100km less fuel used and the new truck isn't even broken in yet. Not bad at all! :cool:

Prestonia24

02-14-2007, 13:30

I've just passed the 7500 mile mark (270 engine hours according to the computer) in my truck. (purchased almost 8 months ago), and have been seeing progressively better mpg gains.

I tend to drive about 200-300 miles a week in my truck depending on how many trips to the GFs house I make (shes in laguna beach aka 44miles each way). Depending on how I drive ill get between 16 and 23mpg on the fwy and 12 to 15 on streets.

upon my last trip to vegas in december I did a test on fuel mileage.

on the way to: 290mi, avg speed 80-85mph. fuel economy (hand calc) 13.2mpg.

the way back: 291mi, avg speed 67mph (1800rpm). set the cruise control, even over the cajon pass. fuel economy 22mpg. made it on a half tank....
(before the pass the dic estimated economy was 23mpg, and its spot on)

moral of the story. keep it under 75 and save some fuel.

-Cam

larryh1

02-19-2007, 09:29

I have 5,000 miles on mine.....I am not heavy footed, mostly highway driving, usually drive around 70 to 75 mph. I cannot get better than 14.5. It has been the same on all tanks. I am very disappointed.
I just finished my first long pull. I have done some short ones to properly break in everything. I varied the speed between 55 and 70 during breakin. Pulling a 30ft toy hauler, 10,000lbs loaded, 500 miles. Speed - 65/70. 8.5 MPG!!! I am not happy at all!! :( Can I hope for better or do I need to make a trip to the dealer to check for a problem?

cowboywildbill

02-20-2007, 04:38

We are just comming up on 1,000 miles on our 07. I am only seeing 10.5 so far just short trips. I was seeing 15.5 and better on our 06 before it got wrecked. I hope this 07 does better. I'll blame it on winter and not being broke in yet. It is identical to the 06 except mpg wise.

Dihrdbowti

02-21-2007, 16:24

Well my DIC shows about 14 in town hand calculated it's 15 on average. Long trip from Reno to Victorville and back DIC showed 21 and by hand it was 22. DIC also shows that I have used about 1 gallon more than what i put in..
13000 miles 07 CC classic LBZ completely stock.

ramblinrodney

02-24-2007, 19:21

14.3 for me, see what summer time brings. My 05 with the same temp. 19.6

Bravo Whiskey 21

02-24-2007, 23:39

GMC 2500HD Crew 6.5 bed LBZ W/ DiamondBack Cover +/- 300# in bed.
SE region of PA. Short hops to football practice, staples(beer,wine), project site visits(work out of my Van), family typical runs w/ the 15mile run on the highway to get here and there, mostly Suburban mix type driving. I drive more towards the aggresive side but not like an A hole.
13.5K miles best average by hand calc. is 15.6/ Straight HW is aroung 18.5
pulling a light 3500# Boston Whaler.

cowboywildbill

02-25-2007, 11:30

We filled up in Thurmont Md. I added some Lucas fuel treatment and also DP cetane boost to the fill up. Then we drove to the Farm show complex in Harrisburg, PA. and back. About 140 miles round trip. 55 to 65 mph. semi Hwy and urban driving. The computer said I averaged 15.9 mpg. The truck only has 1,070 miles on it. I guess I will know how accurate the computer is after I fill up agin and hand calculate.

cowboywildbill

02-27-2007, 12:52

Filled up on the way on Hwy 15 and ran 108 miles at semi hwy speeds. 55 and 65 mostly. Went to Harrisburg, Pa and back to Rocky Ridge, Md. Drove 4 miles to town and topped it off 7 gals. We averaged 15.7 mpg. hand calculated. The computer said we averaged 15.8 and said we used 6.9 gals.
It was pretty acurrate. Only have about 1100 miles on the truck, so it should get better. We were empty not towing and it was 35 to 40 f. outside.
Just running around town and back country roads the computer say's about 13 mpg.

rhymas

03-03-2007, 21:58

I just got mine Wednesday (crew cab, 4x4, 6 1/2 foot bed), my first tank was 13.7 mpg. So far all of my driving has been city. My previous truck was a 2005 extra cab Z71, it was nice, but I really like the diesel so far.

Kennedy

03-06-2007, 13:01

Has anybody tried condition consistent back to back runs in 5th vs 6th gear?

I'm wondering if we won't be surprised. 60 mph is my suggested speed for this test...

mschuyler

03-23-2007, 18:31

Prestonia24

03-24-2007, 21:30

Got the LBZ full up from the dealer. Just filled up for the first time. 16.66mpg. Diesel is now cheaper than even regular gas around here. First time I filled a tank over $75.00 worth. the system just stopped right at $75. I had to reinsert my card and do another coupla gallons! Anyway, for a first tank and mostly city driving I thought that was okay mileage.

That's actually pretty damn good considering that it's fresh off the lot and hasn't had a chance to break in yet. Mine didn't get consistent 16 (city)/18 (combined) until i hit nearly 5k miles and had already changed the Oil.

Diesel is slightly cheaper than 87 RUG here in Los Angeles right now, but about 3 months ago, Gas was near $2.0X and i was still paying $2.55

As i drove past a bunch of stations today, Cheapest 87RUG - 2.98 (ARCO aka Cheap-Gas) And Diesel from my favorite station was a modest 2.77 (up from 2.68 Last Week)

The Gas vs Diesel price is sort of a wash, as one can't really predict why all of a sudden prices shoot the way they do.

http://img132.imageshack.us/img132/6837/fueleconasof022607ui6.jpg

Notes:

This is not the most conclusive (as far as fuel prices go, i may not have shopped around the best).
There are several fill-ups missing, most notably in the beginning and some in the middle, due to lost receipts :-P
Note the best tank avg of 18+ mpg (made it back from Vegas on 1/2 tank, getting 22mpg @ 67mph, then kinda wasted the 2nd half of the tank.

I still like my Diesel though. Don't think i'll go back to a Gasser anytime soon, not in a truck anyways.

FBJR

04-03-2007, 15:00

I have installed the Edge Evolution and have the #3 tune installed. Using the DIC alot, but it seems very close to actual when I compare.

I used to get 16-18 with mixed driving, now I am getting over 20 with mixed driving :D

I do hear a little more rattle, but not much and for this MPG I can live with it.

Ramster21

04-12-2007, 00:51

Roughly 18 - 20 MPG if I don't put my foot in it, but what the sense, if you can't show off. :cool:

etkeeny

04-12-2007, 10:22

I've been averaging just over 17 with mine, As of this morning I now have 1011 miles on it, havent taken any long trips yet. mostly city driving and about 100 miles towing my 16,000 trailer/backhoe.

Barkbuster

04-12-2007, 10:47

My most recent tank gave 19.6, and that was winter blend. Must be breakin in a bit with 7000 miles. I`ll be doing a trip this weekend of 400 miles so hoping to break the 20mpg barrier

mschuyler

04-13-2007, 18:01

16.7mpg hand calculated. DIC said 1mpg less. I love this 34 gal tank!

Barkbuster

04-15-2007, 19:51

466 miles on the tank netted 21.47mpg my new best ever! 80 miles was local to work and back. the rest was cruising @ 65mph. When the gauge was 1/2 it showed 410 mile and I was hoping it was getting 24mpg but the gauge is not real true. When I filled, the gauge was 1 mark below 1/2 and took 21.7 gallons.

steak2k1

04-26-2007, 23:29

I have an 06 LBZ CC SB, and have been seeing anywhere from 14mpg (all streets mostly), to about 18 on the highway

Exactly what I was gettin while it was a stock motor. Now I ain't callin BS on those that say 20mpg + on a stock motor...but yaz got me wonderin for sure..!!:confused:

Now....after mods

City 16.2 - @ 35 mph or better
Hwy 20.2 - @ 75 mph

Truck is MT, stock tires (60 psi front -50 back), and running the Banks at Level 4, driving was done daytime, springtime and on fairly flat terrain.

To get any better, I think I'll need a sail.:cool:

rgds,

stk;)

Zacc

05-16-2007, 21:19

13.5 with 45 miles on the clock.

Is it broke in yet?

.

.

.

Dakster

05-17-2007, 04:51

To get any better, I think I'll need a sail.:cool:

rgds,

stk;)

You've already got a sail. Those clever marketing guys just call it a tailgate.:D

Keep your tailgate up... That works as a great sail.:eek: It just doesn't help mileage...:(

EdHale

05-20-2007, 20:24

I towed my 19' boat (4500 pounds boat and trailer) 210 miles Friday night and it got 16.1 mpg at 65 mph, 99% interstate highway calculated. On the return trip without the boat also at 65 mph, 20.3 mpg calculated. I had the a/c on both ways. Ed

gophergunner

05-25-2007, 12:15

2006 sierra quad cab, 4x4, best i ever got was 25 mpg highway doing about 110 km/hr

Destroyer

05-27-2007, 00:48

I have a 2500 HD Crew cab 4 inch lift LBZ I used to get about 9.9 towing(8400lbs Fifth wheel) and about 14.3 not towing on the Highway. I put on a Banks Monster exhaust, and Banks cold air intake, and I used a Superchip programmer. Can you say Rocket. I towed a Aluminum car trailer and a Chevy Caviler 400 miles with the new upgrades with 4100 pounds and 15.7 mpg I could not be happier. (55-65) Climbed the Grapevine in California twice during this trip. I was very reluctant to do anything to my baby. But it seems this was the right choice. Goes very fast if you let it, or make it. I look forward to visiting the pumps again. 500 Hp up from 360hp stock, 740ft lbs torque up from 650, according to the very happy parts man who sold me all this shiney stuff for $1800.00 . I figure I am saving 10.00 per 100 miles driven just while towing mind you and you gotta love that. Now if I can just keep from showing off at every stop light I will be doing very well.

hockeyjac

05-28-2007, 12:26

I just filled the tank for the first time and I got 17.2 Mpg and that was a combination of City and Highway miles. It includes a 50 minute sit and inch along stretch due to an accident. I am quite pleased. Towing a 8000 lb trailer this week so I will let you know the mileage after this trip.:) :)

EdHale

05-29-2007, 19:07

Destroyer

05-31-2007, 11:15

I get 20 mpg at 65 mph not towing on average all highway. This past weekend I towed a 9,000 boat (total weight including trailer) with a T-Top 225 miles all highway at 60-65 mph and it got 12 mpg. Not too bad I think. Comments? Ed
I towed a car and trailer a Chevy caviler on a Car trailer on dolly. A manual calculation of the fuel showed 15.6 mpg. I have a Banks intake with a Banks Monster exhaust with a Superchip tuner. Lifted 4 inches on 33s. I want to say the car and trailer were around 5500 or so.

cowboywildbill

06-06-2007, 05:31

We have about 3200 miles on out 07 CC 3500 dually LBZ, and I can see the milage getting better everyday. Towing or empty. Hope it keeps climbing. I am getting a little better mpg than our 02 did. Last tank 10.7 towing a 40' gooseneck 14,500 lb LQ HT. and 17.3 empty hwy. It drops to 14.5 to 15.5 in town.

clb33fyxj

06-09-2007, 14:18

i see around 18-18+ change cruising at 75. truck has 28,000 miles on it and is all stock... for now :cool:

2free2work

06-10-2007, 17:27

Just hit 11000 miles. We pull a 15K lb fifth-wheel full-time.
Getting avg 10 towing, mixed terrain. Worst was 8.5 uphill
against 40mph breeze.
At 70 on the freeway it's rock solid at 20mpg.

Got to LOVE the Duramax.

rubylee

06-13-2007, 00:09

my 2006 2500HD Reg. Cab W/8' bed 4X4 with the Allison auto trans and about 9766 miles on it ( I bought it in July of 06) gets around 15mpg combo. I have been told they need 20K miles before you get the tru mileage. I hear it takes that many miles to break in the engine. I sure hope I can get mileage numbers like some of you other guys are getting. I'm very impressed with the mileage numbers posted.

Rubylee Bruce

Goofball

07-06-2007, 13:44

ChuckZ

07-14-2007, 14:17

I have a 2006 LBZ (3500 ext. cab) with just over 186000. running empty, at posted speed, she gets 22 to 23. Pulling rvs, no matter what the size, she gets 11 to 12. With the Hypertech, it increases 1.5 mph loaded and 2 mph empty.

BradL07

07-15-2007, 18:14

Running unloaded on the highway - meaning not towing anything - I got a high of 19.7 mpg in my '07 LBZ CC SWB 4WD, running 70-75 mph. I think that's the highest mpg I've ever gotten from a 4WD pickup, gas or diesel ('01 LB7).

Ramster21

07-15-2007, 23:17

Installed my Edge Juice w/Attitude and getting 19 city and 24 hwy.:cool:

DmaxMaverick

07-15-2007, 23:24

Installed my Edge Juice w/Attitude and getting 19 city and 24 hwy.:cool:
Calculate it by hand, with a calculator if necessary. Try not to cry, the math don't lie (but your DIC will).

pimajim

07-16-2007, 12:38

My 2500HD/duramax, allison has gotten 20 empty, 10 towing a 35ft 5th wheel, 15 with a 3000lb camper on its back. Rarely changes unless extreme winds.
City or highway.

steak2k1

08-20-2007, 19:18

MT: on level ground - no head nor tail wind
18.5-19mpg

Towing: 5000lb 22' TT, w/4 in the truck and the bed loaded with camping gear and too much Beer..(nahh)
12.6 (oh yea, that was in BC and in the Mountains).

Both Readings with Banks on Level 4.

who cares. Awesome truck and I LOVE it.!! (Drew Carey voice):D

cheers,

stk

DarylB

08-28-2007, 18:49

Bone stock LBZ, around 3200 miles. First tank that I checked - 18.25

bpfaeh

08-30-2007, 18:53

Long time lurker here, but my first post! I picked up my new 2007 GMC Sierra CC 4x4 a couple weeks ago....had 68 miles on the odometer when I picked it up....drove it home from Michigan and got 20.1 hand calc'ed on the highway....combo driving on the last two tanks and got 17.5 both times....Im really happy so far!!

David Lunsford

09-06-2007, 01:06

Installed my Edge Juice w/Attitude and getting 19 city and 24 hwy.:cool:

What kind of mileage were you getting before the modifications?

Thanks,
David

David Lunsford

09-06-2007, 01:13

I've got a 2006 2500 HD Crew Cab and my milage has went to crap. I use to get about 16 mpg but out of the blue it has dropped to 13.3 mpg. I don't drive it any different....keep it serviced on time etc....any ideas as to why?? I have 27687 miles on it. Oh yea, and when I pull my Ranger boat now.....10.3 mpg.....never any problems with it but I don't know what has happened to my fuel milage.

Thanks,
Bob

Hey Bob,
Are you still getting crappie MPG? I've got an 07 sierrra classic crew cab 4x4 an get around 15 mpg hwy at 75 ~ 80 MPH. Pulling 30ft camper only 10mpg.

Thanks,
David

RichC

09-06-2007, 17:36

I have an 06 LBZ with 5" Exhaust cat back, Bully Dog Triple Dog Downlaoder. Worst milage I have had on a diesel, including 6.2,3-6.5 and three Duramax. It may have to go. Has 29,000 miles. Got 9 mpg today towing two large containers About 8,000 lbs total. Crappie milage. Want my 02 back.

DarylB

09-06-2007, 19:58

lb7lbz

09-11-2007, 15:15

put about 4000 miles on the 06 cc short bed with lbz. every tank checked by the dic and hand calced as well. dic says anywhere from 17.5 to 18, actual hand calc says always a 1/2 mile per gallon better, so around 18 to 18.5. most of its miles are the wife driving it back and forth to work 40 miles round trip,so not really long enough to let it strech its legs. i have seen the truck get 21 mpg at best.havnt towed with it yet and it still isnt broke in yet(19000 miles)love the truck happy with the mpg

Kennedy

09-12-2007, 06:28

If I drive sensibly and run at 62mph mine has been rewarding me with 22mpg and sometimes a shade over. Much better than the upper 17's that I started out with. If I make numerous stops it does start to fall. It likes to get up to temp and stay there. It's taken a lot of tuning to get it there. I believe it's partly the tuning, and partly the break in. I now have about 8k on the clock if memory serves.

cowboywildbill

09-12-2007, 07:44

My mileage seems to be getting better as time & miles add up. I just towed our 40 ft LQ Horse trailer weight 14.5k without horses on a 400 mile round trip to the beach. We averaged 10.2 mpg hand calculated. There was some stop & go traffic. According to the computer our best mpg was at 62 to 65 mph. It seemed to drop more at 55 ? Tried to keep it in 6th gear when I could.It was actually saying 12.9 at 62 and above for some stretches. 5,400 miles on truck so far.

mr. monte

10-16-2007, 07:55

just took a trip with mine and NO trailer, and about 8500 miles on the clock now...
one tank was 19.5 w/ my calculator, the other tank I got 21.3 :eek::p:D:cool:

DieselMonk

10-24-2007, 03:51

Took a trip to the valley few days ago and got anything between 10.8 and11.1 L /100km that is about 21mpg, running on the highway @ 65mph constant. Didnt matter if empty or loaded with 300kg. Got 13000km on the clock now. So far the milage on my Duramax is still improving. It does make a difference running with the air conditioner on or off, also running 6th gear over 90km/h. So far I am really happy with that, as I used to get 12 to 14 mpg with my old 6.0L 2500 YukonXL.

cowboywildbill

10-24-2007, 08:20

Iv'e noticed our mpg is improving running empty about 14 to 16.3 around town & country and 18.6 on hwy. We just turned over 8,000 miles. It has come up since it is getting broke in.

Ezz E

11-12-2007, 09:33

New to the board and I am seeing only 12-14.5 with my LBZ 2007 classic 4x4short bed crew cab 20,000 miles and a 3.73 rear looking for upgrades to increase mpg what is out there that is working.
I did get 18 on a 300 mile trip it needs to get better than 14 any help out there. Average load 2000lbs. when towing that is when I see 12-13 mpg.

cowboywildbill

11-12-2007, 14:44

Stop and go traffic and any will knock it down quite a bit. I have seen as bad as 13.5 empty when around town.

steak2k1

11-16-2007, 22:35

2 trip's now for work through BC mountains on # 1 hwy: Calgary to Kelowna
Avg 60-65 mp/hr...avg mpg both trips was 19.8 , and ya I use the DIC...I use it all the time. I also hand calc. and it is out no more than .5 - so whatever.

This is 2 lane mountain driving...Kicking Horse pass, Golden, Rogers pass, Revelstoke etc. some serious ups n downs.!

Truck was MT other than suitcase/laptop, cpl of spools of FCAWire and 4 Jerry cans of Diesel. (way cheaper in Calgary than on the Hwy. (.40-.70cents/gal). no wind, Banks on level 4 running stock tires.

Truck has just about 63,000 miles (102,350km). Still purrrrin.!;)..it will get better but I do think these units need to be worked once in a while..tow a good haul or load up the bed with some weight and drive with it for a while.

cheers,

stk

DuramaxYooper

11-27-2007, 13:16

My 07 Classic Crew Cab - Short Box - LBZ is stock right now - stock tires too and I have about 18,800 miles on her. I make repeated 3 hour trips back and forth in northern Michigan (in the U.P. - the REAL Great White North) and while they are not considered highway, I get decent fuel mileage. Since about the 10K mile mark I have been consistent with 19.6 to 20 mpg on this 3 hour trip running about 65 mph. I pass through small towns and have to slow down and because I have a wife and 2 small kids, we have to stop every friggin hour - but I am pleased with that mileage. Beats the hell out of my mini-van years.

Around town - it really varies. I get between 14.5 and 16.5 mpg depending if I am rodding it at all. Its not my daily driver, so I tend to like to RUN IT when I do drive it.

Winter blend DOES change this mileage - maybe 1.5 mpg or so. (ALL of this is hand calculated)

And really - who BUYS this truck for "mileage" anyway?

Its just a friggin awesome truck. LOVE the DMAX and ALLISON.

AVEX

11-27-2007, 22:19

My '05 had 40k on it when I bought it. I stole this truck for 27k. LT Fully loaded CC 4WD and all the bells and whistles. I dumped an injector at about 50k shutting down the left bank. Recall thank gawd! Before this happened I was happily getting 17 avg. Since I have gotten the truck back I have not broke 14! What the he$$ is going on??? Can someone tell me? I would also like some input regarding the Hypertech Programmer III. I was told that this was the application for my truck. I travel around 60k miles per year. I need the fuel mileage. Any help or suggestions??

GNOD

01-07-2008, 10:13

I have a 2006 LBZ and have approz 25000 and only just got over 18 mpg after putting in a banks ram air systems before I was averageing 16 mpg. Most of my driving is 70 miles daily with 60 highway and 10 intown at around 75 mi. Does this sound right? I love the truck though came from a F250 V-10.

IdahoRob

01-07-2008, 15:53

I'm getting around 16 city and 19 highway

Bravo Whiskey 21

02-14-2008, 20:28

27500miles. Suburban type driving 14.5 - 16.5
High way loaded and gunn'in. 18.5
high way and keep'in my foot out of it ( 1800 RPM'S) 22-23.5

Powerplant Kick's a$$. Stock and I can beat/ control situation most of the time::D:D

Bravo Whiskey 21

03-13-2008, 19:44

March 11, 08
LBZ/ see prior post
winter mix same type driving
Last two fill ups(21 gallons +/-
15.3/15.7
Last Fill up was @ $4.06 WTF:mad:

hapaschold

03-15-2008, 17:49

last couple tanks for me,
hess diesel
hanging in at 17mpg.
but i think the fact lowering the speed limit on 1/3 rd of my parkway commute has helped

just added a bully dog pup programmer. like to see what happens now !

EdHale

03-23-2008, 05:20

Even though it was hard to do, I drove to the lake Thursday evening at 65 mph while on the interstate and 62 on the two lane roads just to see how the mileage would change from my usual 75 mph interstate and still 62 on the two lane sections. This trip is a total of 210 miles and 80% is interstate. I did not have the a/c on. On arrival at the lake the DIC had been steady on 21.0 mpg for over 10 miles with no change. It is usually slightly conservative on my truck, so I feel certain I was getting 21.0 or maybe just a tad more. I won't know for sure until I fill up on the way back home this afternoon and hand calculate it. I usually see about 16-17 mpg in town, but then I have a very light foot (I get honked at pulling away from red lights all the time).

Maybe I'm just lucky and got a truck that can produce good efficiency, or maybe my conservative driving is the major factor. Whatever the cause or causes, I'm glad to see this kind of efficiency, but I'm the first to admit it is hard to not punch it occasionally. Ed

BlackMAxx

03-26-2008, 07:25

Hey all.. I have a 06 GMC short bed with a little over 20000 miles on it. Last summer and early fall I was getting just shy of 23 MPG on the highway. Running between 70-75 mph. I went up from the factory size tires. From 245-16 to 265-16. I didn't pay that much attintion to the milage after that. Then in October I went on a trip. From WV to WY on a hunt and visit. My milage on the highway was 16.3 at best. Now, running around town and such is 12.5 at best. What in the world happened to my milage.
The service guy at the shop told me it was because I changed the size on the tires. I just can't believe that 1 size would cut my milage that much.. Any help would be appriciated.

JohnC

03-26-2008, 14:16

Did you adjust the speedometer to compensate for the tire change?

23 mpg at 75 mph sounds a little fishy to me. Are you sure? Was that by the DIC or calculated?

BlackMAxx

03-27-2008, 14:47

No, I did not adjust the speedometer for the bigger tires..
And as for the MPG. It was just shy of 23mpg and I got it off of the DIC and I calculated it also.

JohnC

03-27-2008, 15:27

If you didn't correct the speedo then your actual miles traveled is greater than indicated by the odometer. This will throw both hand calculations and tthe DIC off toward the low side. Additionally, you could now be looking at winter blended fuel.

If you really got 23 at 70-75mph I'm envious. the best I've been able to manage is 22 at 65 mph. Is yours 2WD?

BlackMAxx

03-27-2008, 19:36

No It's 4 wheel drive. And I just went out and got the paper that I wrote on last summer. The highest was 22.7mpg. Right after a fill-up and hit the interstate.

I was told by a guy that he had the gasket around the turbo,(not sure which one) had a crack in it, and he was getting very poor milage.

larryh1

04-28-2008, 10:43

I am running the Hypertech. Not real pleased. 16.5 Hwy, 14 city. A speed shop here said the Bullydog is better. I'll wait to read on this forum how it works out. Oh, I am impressed with the towing using the Hypertech. I get 12hwy, but the power delivery and shift points make it very smooth to drive. 30ft toyhauler, loaded with motorcycles and tools.

I am also going to look into exhaust and intake changes. I am already running a K&N filter (only).

Larry

Fire Escape

08-31-2008, 22:13

Bone stock (even the tires) 07 Silverado Classic, 4x4, LT3, Crew Cab, Long Bed, now up to 41,000 miles. Best milage 21 mpg calculated - just over 700 miles on one tank of fuel but I was taking it pretty easy on the way home, what with very few fuel stations open at 0200. New Hampshire to Big Pine Key and back in January (4,000+ miles) with a kayak on the roof and a DR 650SE on the rear bumper - 18 mpg calculated. New Hampshire to Daytona and back (2,600 miles) with an 8 1/2x20 trailer and 5 bikes - 11.8 mpg (left in -13F with a big dose of fuel additive to ungel the fuel). New Hampshire to Big Pine Key and back (4,000+ miles) in May with a 16 1/2' boat - 16.5 mpg. I have seen better than 22 mpg for trips but always mix in enough around town stuff to kill the average before refueling, it will get down in the 14 range with enough cold start, shut off in 1/2 mile type driving.

Bruce

Doccat

09-26-2008, 04:02

Just took a trip (Ga. to Tenn. and back) I didn't speed and no heavy load. 21mpg. to 22mpg. Stock. Check mileage both ways. The average and miles /gallons. I had order a bully dog before the trip. Just entered the program last night will update later.

EdHale

09-26-2008, 07:01

I drove from Spring City, TN to just south of the Atlanta airport last weekend. I drove at 60mph on cruise, no a/c, and was very light on the throttle. The DIC said 23.4 mpg. This is the best I have seen and this was a 208 mile trip.

moss6

10-20-2008, 14:23

700 mile round trip through the Texas hill country this week end, for some golf at Horseshoe bay on Lake LBJ. Pretty much constant 76mph except for towns and passing on two lanes where the speed can get up to 95mph to get around quickly in some short passing areas. When we got there we were sitting on 18.2MPG after getting back to Lubbock (about 2,400 feet higher) mileage had dropped to 17.9mpg, both DCI which has always been so accurate that I never check by hand anymore. Speedo is about 2.25mph faster than what the GPS shows so I set cruise by GPS. Rocky Mountain Radar does in fact block the cops radar as is easily seen by the expressions on their faces.
Randy

TJNE

10-22-2008, 13:20

I have an 07 classic (all stock) LBZ 66k miles and I get 12-13 mpg around town and 18-19 on a trip. How accurate is the DIC when watching milage? Mine seems low. I expected a little more, any suggestions to squeeze more mpg's?

DarylB

06-26-2009, 12:19

Best tank so far 19.02mpg @65mph crusing speed. Going to slow down a bit more this next tank and see if I can squeeze a bit more out

16.5-17mpg average is the norm for me. 28k miles currently.

sb359

09-24-2009, 19:49

Vancouver, BC. to Colorado Springs,CO and back, pulling a 6800lb Bigfoot RV 13.2 MPG.(DIC)

mmcm267

12-02-2009, 14:25

Just picked up my 07 and driving home on the flat: first tank 19.5 mpg and the seond tank through the mountains between Nashville and Atlanta on I-24 18 .5 mpg. I was running 70-75 (1900-2000 Rpm) in Drive.;)

I wonder if I shifted to Manual if the TC will stay locked up better?:rolleyes:

TJNE

12-02-2009, 14:51

How many miles and is is stock? Stock tires, air filter, exhaust, intake, etc.

Just picked up my 07 and driving home on the flat: first tank 19.5 mpg and the seond tank through the mountains between Nashville and Atlanta on I-24 18 .5 mpg. I was running 70-75 (1900-2000 Rpm) in Drive.;)

I wonder if I shifted to Manual if the TC will stay locked up better?:rolleyes:

mmcm267

12-02-2009, 14:55

Duh!!!:rolleyes: Sorry about that. It is stock with 36K mi.;) But not for long!!

gilbert roark

03-13-2011, 10:15

Friday the abs and brake light came on and the ecm went dead.I tow the truck to a chev on sat. and they said the ecm was fried.any one having this problem.

joe106

12-30-2011, 15:14

I think all you guys are full of ****! I have an 06 LBZ with a hypertec, AFE intake, & MBRP cat back exhaust. I do not get on this truck!!! PERIOD. Absolute best around town is 12mpg. on the highway not towing anything I may get maybe 18. SBCC weighs maybe 6500lbs, what gives with all these stories?

DmaxMaverick

12-30-2011, 17:17

YMMV. True that.

NutNbutGMC

12-30-2011, 17:42

YMMV. True that.
Mine varies to the low side. If I could get even 15 MPG I'd throw a party...

12 MPG + / - is the best it does....regardless of load

.

JohnC

12-30-2011, 19:07

Guess I'm full of ****. 16-18 over all, 20-21 highway at 65 mph. Wasn't as good overall when I lived in the mountains.

gimpyhauler

01-01-2012, 13:38

I'm in Sacramento, CA presently. I have a LB/CC, 18" rims/tires, and drive to and from my property in South Central Oregon. Over the mountains between and have never averaged less than 17mpg on cruise control at (mostly) 73mph. I haven't taken the trip since getting my BullyDog. I'm waiting to see what the difference will be. (PS: 162,000mi.)

GMC D-Max

01-02-2012, 18:10

Not thrilled with my mileage, but I love the truck.

On a 1600mi. trip from Minn. to western Washington, average speed over 70mph... 16mpg.

Mixed driving (about 60% in town, 40% highway)... 14.5.

THEFERMANATOR

01-04-2012, 11:17

Just got done tuning an 06 LLY/LBZ, and he went from getting 18-19 running 65 with his bullydog triple dog to 21.5 now doing the same exact trip except now with an EFILIVE tune I put in it for him. I believe he said stock he was getting about 17-18. Stock tuning in teh LBZ isn't the best for milage IMHO, theres no reason to be holding 5-6 pounds of boost while running 55 with no trailer on a flat road. It does make for a responsive truck, but is hurting the milage.

gimpyhauler

01-11-2012, 14:53

Mark Rinker

01-11-2012, 21:58

My observations are have been that LBZ and LMM powered trucks get about 15% -20% less MPG than the LB7s when driven unloaded.

When towing, the LMMs do a little better than the LBZs, and only about 5% - 10% less than their LB7 predecessors, with much more stock power and a much greater ability to diffuse heat from the cooling stack. The LMM is a major improvement over the LB7 in the power department for just a little more fuel consumption, and still a measureable improvement over the LBZ family in both MPG and heat management.

After 11 years of production, team Duramax continues to improve...

THEFERMANATOR

01-17-2012, 14:16

Sure would like to hear more about that tune. That is an impressive mileage gain for cruising. :confused:

This was with an EFILIVE tune that I got from another forum. I tweakd it slightly to smooth it out, but it is a pretty basic tune. About 2-4 degrees more timing in the cruise area, and the boost was lowered about 3-4 pounds at cruise as well as opened up the turbo vanes. It made it a little sluggish to respond to throttle changes, but it was a good trade-off for the milage gains. Plus it was a DSP5 tune so all he had to do was flip the switch on the dash and it came right back to life.

My observations are have been that LBZ and LMM powered trucks get about 15% -20% less MPG than the LB7s when driven unloaded.

When towing, the LMMs do a little better than the LBZs, and only about 5% - 10% less than their LB7 predecessors, with much more stock power and a much greater ability to diffuse heat from the cooling stack. The LMM is a major improvement over the LB7 in the power department for just a little more fuel consumption, and still a measureable improvement over the LBZ family in both MPG and heat management.

After 11 years of production, team Duramax continues to improve...
With a basic tune the LBZ and LMM can both get almost teh same milage as the LB7's, and like you pointed out they are so much more refined and powerful. After tuning and driving one, I kick myself for swapping in a LB7 into my BURB, the LBZ would have been worth the extra effort in the end.

MadPainter

02-13-2012, 20:23

hi i have a 2006 with 94000 mi with the lbz and if i keep it uner 1700 rpm on the hwy i get 23.2 mpg's

BigRabbitMan

09-06-2013, 22:38

For reasons unrelated to mileage, I am going to be using a Banks tuner in my FMC motorhome conversion to the LBZ (there is a thread in the Conversion forum). The tuner has an "economy" setting.

Does anyone have any experience with using this setting in a Banks tuner. Any thoughts on a percentage improvement in mileage that would be reasonable to expect vs the stock setting. I will be basically running "loaded" all of the time as the coach weighs about 14,500 lbs.

Scooby

03-27-2017, 08:13

I am wanting to get the best MPG out of my new to me 2007 2500 CC LBZ with 248k on the clock. I drive MOSTLY unloaded, in Florida, and im only seeing 16 -17 mpg. The tires on the truck are very new 285/75/16 , and I do correct for larger tire size in mileage calculations, and use GPS to compare. Im wondering how much the larger tires effect the fuel mileage, and what difference I would see if I went back to the 245/75/16 size that came on the truck. From what I have found, my tires are 2" taller, so it raises the truck 1 inch. I have always heard lower truck = better mileage, but I dont know how much 1 inch will change things. Any experience / suggestions would be greatly appreciated.
I am also planning to install a DSP5 and EFI tunes at some point. I want the economy tune, and the ability to switch to more power when I need it. I think this would give the best results for better mileage, over messing with the tires.