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Discussion Starter #1
There is alot of talk out there about various aftermarket adds for the duramax(I'm running a 2500 HD Crew). What I'm curious about is what kind of MPG increases are people seeing. I recently added the edge juice with attitude and have not seen much of an inrease in MPG(the first couple of weeks was lower and took a little off the tires too). I've experimented with the different stages on the edge juice and found almost no difference between stages 1-3 for MPG ( the power difference is very noticable). The truck is still breaking in (5000 miles) and I get between 15 and 19 MPG :) depending on my speed. At 70 mph in stage 1 I'm at about 16.5 MPG :mad:. If anyone has any other comparison it would be helpful.
 

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2005 Duramax

I'm very disappointed with my '05. I had a '01 that was getting between 22 and 24 MPG when I drove between 65 and 75 on the highway. It got 18 - 19 in town. With my '05 that now has 18K miles, I'm lucky to get 16 MPG on the highway and 14.9 in town. Frankly, the power difference between the two trucks pulling a 14K lb load is not that noticable to me (which draws me down to 11 MPG). Hence, I spent $20K to get a new CD player and tires -- while giving up 5 - 6 MPG. My dealer indicates that it is a known problem for GM, and that they are working on a software fix. I believe that to be a load of crap. I love the ride and style of the truck, but this economy is making me consider switching to (God Help Me) ... a Ford. My dad has the same truck with a Ford emblem that is regularly posting 23 MPG on the highway.
 

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Not good to hear for me......Just purchased an 05 crewcab 4x4 short D/A....Has around 650 miles on it......got it for less than I paid for the 02 I had and lowered my payment by 35$......I was around 20 on the highway in the 02 and I hope this 05 does the same.
 

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i dont think you'll get that high running stock :(
 

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I have a 05 crew long, with edge attitude and juice, no muffler, and k&n, and i am getting 21-23 in level five. When i am pulling my 48' goosesneck in level 2 (16000lb) i get about 12 at 72 mph.
 

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fuel mileage

I have heard so much on fuel mileage I don't know how some are getting it. I average 17mpg some highway some city and some towing. I have yet to get out on the interstate unloaded to see what it will do. I will say that I just made a trip to Pennsylvania with a 22'Gooseneck and was very pleased with the performance. I'm running the BullyDog cat-back 4" S/S,AEM brute force intake and Edge EZ module. Towing in level 1 with many miles of 7-8% grades and 13 motorcycles on the trailer(about 8200lbs with trailer) I averaged 13mpg. Ok numbers under the circumstances. Many D/A owners in town say once they reached 20-25k miles they had considerable increases in mpg. ;)
 

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Mpg

Wow every body is saying 15-17 even 20 to 21mpg. I have a 05 with a 6inch lift a 35's for tires with approx 6000 miles on it. im getting a whole 11 mpg. Are the bigger tires realy lowering my mpg that much or is the computer not calculating right or is my math wrong. I wish I was getting 15-17 mpg.
 

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Are taking in account for the bigger tire size? Is your speedo recalibrated for the 35s? If not you would have to add the % off your speedo is off to your miles driven. Also, I know some people don't hand calculate their mileage, they just go by the DIC. My DIC was off by about 2-3 mpg (high) from what I was actually getting. You throw a programmer on and it throws it off even more. When I first bought my truck and had the stock tires on it, my DIC registered anywhere from 25-28mpg. I actually got around 19-21mpg on what we call highways here in Alaska. Just my 2 cents!
 

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That's quite a bit of rolling resistance and loss of aerodynamics...but I wouldn't think it would be that extreme of a difference...
 

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my '05 gmc 1 ton dually is getting 13.8 period just about, its all stock and i am wanting to do anything to it to help, i had an 01 dually and it had 140k on it and was getting around 22-26 stock. i am very disappointed in the fuel mileage on this 05
 

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Was your 01 a duramax or a 6.5L? I forgot the first year for the d-max.....
 

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mileage

So, I am not the only 05 owner who is unhappy with the mileage. I got 18 twice at 60-62mph on highway. Couple times I checked it it was 13, no load or trailer.KY
 

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Cummins, you have an 05 duramax or an 05 cummins? I'm confuzzled!!!
 

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Duramax

I have the '05 Duramax, I traded a 01 Cummins in for the Chevy. I seems the new Cummins are almost as bad on fuel ecomomy as the Duramax. I was expecting 22-23 mpg when I bought the truck from my son. I had heard the new Cummins was getting over 20mpg, too. That was not true, though it should be. I think the three truck companies are more interested in out doing each other power wise. I guess if fuel was still 1.28 I wouldn't be trying to figure out what to do, get a different truck, put in a chip thing, go back to an older model, or make my own bio-fuel.
I chose the Cummmins web name cause I figured no one would have taken it already, on this site, and I think it is, was? a real good engine.KY
 

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Well it all depends on how many miles are on the engine and what kind of mods are done to it. I just bought an 03 Cummins with 92k miles. I had to go to south dakota to pick it up, and drove it all the way back home to indianapolis. I got 18.4 mpg @ 80 mph and when I got closer to Indy I slowed down (cuz I know where the cops hide!! lol) to about 60 and reset the overhead console and it told me 24.3 mpg. It was completely stock too. I asked a lot of people if the overhead calc was reliable and they said it was very reliable until you chip it, then it tends to lie to you. I have chipped mine, but even with the chip I have hand calculated very close figures compared to stock. They are slightly less, but not by more than 1 mpg. Even so I'm way happy to have a combined city/highway average of 20-22 mpg vs about 16-17 in my old powerstroke.
 

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Cummins

Wow, it would be great to get 24 mpg. Is it the 12 valve, I heard the 12 valve ones were a little better than my 01 24 valve. I don't remember seeing much of an improvement on mileage when I got more miles on the Dodge, or my Chevy. The dealer said " oh, when you get to 12,000 miles you will see a big jump in miles per gallon" , did not happen.(with the Chevy). Wow, that is low miles for a '99, my '01 had 146,000 when I traded.KY
 

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No, it's an 03 24v common rail. Actually 12,000 miles isn't really broken in. From what i've been told you have to go a lot more than that, like 30 or 40 plus before it really begins to get better, and it's suppoed to get better and better up to 100+
 

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broke in

Wow, that is a lot of miles. I don't think my Cummins changed much from when it was 6000 to 146,000 miles, (the miles per gallon). I guess the engines are different.KY
 

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Maybe it did and maybe it didn't, hard telling. They always say that every engine is different even thought they're built to the exact same specs....
 
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