Duramax Mileage Getting Better...

[tbyrne]

I've read some posts where people have said that their fuel mileage has increased with mileage. I've found this to be the case with my '05 Sierra also. The DIC tends to read about 2 MPG high (usually hand calculate when I fill up). Today I flipped to that screen and see that it's at about 19.6. That will put me right around a real 17.5. Driving style and location is usually the same all the time and I haven't done anything different with this tank of fuel. Much better than the 9 MPG that I used to see what the big block!

[Machine]

I've read some posts where people have said that their fuel mileage has increased with mileage. I've found this to be the case with my '05 Sierra also. The DIC tends to read about 2 MPG high (usually hand calculate when I fill up). Today I flipped to that screen and see that it's at about 19.6. That will put me right around a real 17.5. Driving style and location is usually the same all the time and I haven't done anything different with this tank of fuel. Much better than the 9 MPG that I used to see what the big block!

 

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Amen! Are you running additives / cetane boost?

[tbyrne]

I'm not using any additives. It's been awhile since I've layed into it hard and watched the boost but I believe max is about 28-29psi. I am running a Westers "Race" program along with some other mods (Volant induction, MBRP Cool Duals, Suncoast Transmission and converter).

[willieboy]

Father in law has the Westers 90hp tune ('02 2500HD 4x4 Crew), and his real world MPG went from 17-18 to a rather impressive 20-22. Towing he went from ~14 to 17 (boat and slide in). His did get a little better with age. Driving conditions have not really changed except he has plenty of extra power on tap to pass the big rigs on those mtn. passes out west.

[Daubs]

That's good to hear on the Duramax's. I've seen improvement in my Big Block MPG over the course of 30k. Started off in the 8.5-9 range city. I'm now consistently getting over 11 MPG city. But I've got the rattles when I start her. Mechanic buddy says it is double edged sword. The knock is from not so tight tolerances...but that makes for reduced drag on engine = higher HP and better MPG numbers.

 

Me thinks a D-max might be in my future...but that's probably 4-5 years down the road.