I took an all highway trip with no trailer today. Filled up when I left and then stopped at the same gas station when I returned. I saw 19.4 MPG (hand calculated, GPS verified). This was running with the cruise set at 72-73 MPH. The RPMs were at about 2050, 100hp Predator program stacked with the level 2 Edge.

My 22" wheels/tires are about 3" taller than stock. I think this might help the RPMs stay close to that magic range at just over 70.

How many miles are you up to on that thing? I am getting the same MPG's, but varied terrain and varried acceleration with 20,500 miles.

I got 21.1 this past weekend doing 65 mph with the cruise set running empty.......

I'll buy that one. I've seen 18 MPG when cruising for a full tank at 70 mph and virtually no idling, traffic, etc.

Good work!

Just saw 6200 miles when I got home.

19.4 was much better than the 9-10 that I saw while towing last month. Hopefully that will go up to at least 12 soon. I've be pulling a trailer with a "V nose" instead of a flat one so that might help.

what size tires are you guy's running?

I'm running 305/45/22s.

i have been getting 21.0 on last 2 tanks empty. just towed 5900lbs 400 miles this weekend ran 77-80 the whole way and got 16.8 im super happy with that.

Here is a terrifying one...

My dad made a suprise visit this weekend to Sacramento, CA, he lives in Trail, OR. Door to Door is approximately 330 miles, he filled up when he left, and then he filled up when he got into town. The trip down ate up a little more than 12.5 gallons of diesel. I forgot to check what his console said, but do that math thats like 26 mpg.

Of course my Dad is retired, so thats cruising at 60mph.

If Im running the predator on the std tune I get 16-18mpg. cruising at 75mph, will 35" all terrains.

My Lb7 got better, but its stiller better than a gasser...

Oh yeah I forgot to mention it.

I bought the predator for his birthday, but I had to drive up to give it to him and being the loving son I am, I didnt want to give him something that I didnt test first...

In Feb.I got DIC said 14.2 towing 12K Ibs from Md.to Tx 28x8.5 Ft inclosed US Cargo trailer.Truck had 2200 light break in miles,Changed oil to Rotella 15-40 First all around 2200 miles DIC said 19.2,Total 3450mi in Texas said 14.2...April 24th JUST Reset DIC meter and took a Interstate Hyway 100 mile round trip Sunday 68-70 degrees running 63 to 80 but most was 63 mph.Got back in town and hit the button and it said 21.2,>>05 3500 GMC SRW CC LB 4X4 factory 265x75 tires:cool2:

I have a 05 lly, allison stock WITH 2600 MILES ON IT. I BEEN GETTING 16 MPG ON TRIPS. wHAT CAN i DO FOR BETTER MILEAGE. mT 02 GOT 22 MPH ON TRIPS

Your '05 will, give it time.

Idahofox

Occitiger,

You are getting 16-18 mpg with 325's on????? i am just curious because i put 285's on my 2004.5 dmax and was getting 14.5 mpg. i put my stockers back on for the summer and i am now back up to almost 19 mpg. my truck isn't chipped or anything, i just can't believe that it would kill my mileage that bad. its also almost all highway driving. anyone else had this problem??? should i get a programmer??? any imput would be great

Occitiger,

You are getting 16-18 mpg with 325's on????? i am just curious because i put 285's on my 2004.5 dmax and was getting 14.5 mpg. i put my stockers back on for the summer and i am now back up to almost 19 mpg. my truck isn't chipped or anything, i just can't believe that it would kill my mileage that bad. its also almost all highway driving. anyone else had this problem??? should i get a programmer??? any imput would be great

Took a trip from southwest Colorado to Denver last weekend. Took 160 to 285, wolf creek pass and a lot of hilly terrain, about 350 miles. 20.9mpg, made very happy, but I drove the speed limit (65 max) the entire way, no hot-rodding. On the way home, drove normal, and got 19.2mpg. I am very pleased with these figures as the best I had seen prior to this was 17mpg. I now have 15,000 miles, guess that break-in period really does exist!!!

My 05 with 7500 miles was gettin 18 mt before the motor let go. I have owned 6 of these trucks now and none have gotten better with time.

cperrino,

Bigger tires will affect the odometer reading too meaning you are going farther than you think. check your odometer with the mileage markers next time you are on the interstate. mine is about .1 of a mile off with 285's on it.

bullydogpowered,

i had my dealer put the tires on my truck, they said that they can recalibrate the computer so that the tires will be right. i never really checked it when i had my 285's on, but i used my handheld GPS while i was on the interstate with my 245's the other day and it said that i was doing 70 when the speedo was reading 73. and i haven't had it switched back to stock settings. so maybe the it wasn't as bad as the in-dash computer was reading.

thanks

"<HR style="COLOR: #d1d1e1" SIZE=1> <!-- / icon and title --><!-- message -->Occitiger,

You are getting 16-18 mpg with 325's on????? i am just curious because i put 285's on my 2004.5 dmax and was getting 14.5 mpg. i put my stockers back on for the summer and i am now back up to almost 19 mpg. my truck isn't chipped or anything, i just can't believe that it would kill my mileage that bad. its also almost all highway driving. anyone else had this problem??? should i get a programmer??? any imput would be great"


Yep, thats with the Predator though. Eventually I will by myself one, or I might try the superchips(????). So my experience with the predator was one trip from Sacramento, CA to Trail, OR. Driving around 65-80mph.

I have the updated edge and at 80mph, relatively flat, I am almost at 16mpg.
Truck has close to 30k on it though.

So yes, get a programmer. I like the gauges from the attitude. I loved the performance of the predatore(but hated the defueling between shifts) I probably will love it, once I get a predator for my truck and when I go longer before having to rebuild the tranny.

19.7mpg .... 70-75mph... no chips...

I made a trip to NC from Michigan and back. I did the grampa thing and went 62 all the way there and got 21.8. On the way back I had to put in 4 wheel drive all the way through the mountains, about 2 hours and got 20.1. Both ways were hand calculated. But with my remote start, highway driving to work and city driving to kids functions, I get 16.9.:D

I am extremely pleased since my 1998 2500, gasser,std cab only got 8.6.:(

WOW, you guys are getting excellent mileage. I can't wait to purchase my truck next year.

Also, are there any changes for the 2006 GMC Sierra?

Thank you for your answers.

Pete

I wish I knew what was wrong with my truck.... I have 285's on it and a ladder rack and if I crawl anywhere near 70 or more I am lucky to get 13mpg. I have and afeII and magnaflow exhaust and a hypertech but I have never gotten better than 15 empty.

Yep....The winter fuel is finally gone up here too..
20.66 mpg today, hand calculated
100hp predator program
no additive

over 9000 miles and get around 12 mpg hand calculated with corrected speedo. veeeeerrrry disappointed. (especially after Rick Lance has not had mileage increase over time with all of his trucks)

I ran a 2wd f450 power joke rental to Tucson this week. Under 18,000 easy load I got 4 to 5.5 @78. Most hills it slowed down to 65. Empty on the way back 11 is the best so far. I think I will stop complaining about 16 with my 3500 4x4 Duramax.

Mick, i would say that is a little lower than some IF that is highway mileage !?! But you do have a lift and 35" tires that hurt it some too. Mine didnt do very good till after about 20-21,000 miles and then it started coming up on the mileage. Alot has to do with how you drive them too. Hopefully it will get better, you dont have a bad injector do you ? I have seen mine get around 19 or more on a highway trip.

I have 285s with the edge on 2 and i get about 16 usually with my foot in it. It seems like my fuel mileage went up after i got reflashed at 27,000 miles

FASTOYS,

In town I get 11-12 mpg, highway is usually around 12-13mpg. The best I have gotten was with around 2000 miles and that was 15. I know the lift and tires hurt. My last truck had an 8.1L with the same lift and tires. I could get 11-12 mpg highway with that, so the improvement to diesel is very little. Injectors all seem to be within spec according to predator. Not much else I can do. I run stanadyne every tank since new as well.

Now that we are back into the warmer weather and change in Diesel I am noticing an improvement running empty on my last couple tanks. 20.2 and 21.4 per DIC with a mostly highway 80 mile round trip commute (still some cold mornings).
The truck has just over 29,000 miles and is stock. Seems to be a slight improvement with age but it may be my age (I seem to find myself spending more time in inside lane these days) :o:

I ran a 2wd f450 power joke rental to Tucson this week. Under 18,000 easy load I got 4 to 5.5 @78. Most hills it slowed down to 65. Empty on the way back 11 is the best so far. I think I will stop complaining about 16 with my 3500 4x4 Duramax.

Wow. My 2000 Kenworth with 475 HP with 80,000Lbs+ gets the same mileage. it also has 173,000 miles on it.