Just completed a base line economy run on my new D/A CC LLY.


Outside temperature - 25 deg.


Road - Straight and flat for 8 miles, east and west.


Miles on truck at time of test - 113


Speed set at 55mph with Cruise Control


Water Temperature - 200 deg. steady


Oil Pressure - Slightly below 60 psi steady


Transmission Temperature - 100 deg. steady


Based on the DIC Average MPG:


West to East - 22.3 MPG


East to West - 21.5 MPG





That's good enough for the girls I go with!

Those are some good numbers. I would probably get in that ballpark under ideal conditions. I almost always have at least 1/2 ton of cargo and still get 18-19 while cruising at 65 mph.


According to GM you should vary your speed while driving for the first 500 miles (break in procedure). You may want to avoid cruise control for a while. --SS

Dick, are they still running winter blend fuel there? If so expect those numbers to go up! FWIW for some reason the best mileage (25.3) I ever got was a 300 mile round trip with a couple passes, twisty and up and down highway, about 40% of it was at 55mph and 60% at 60mph. I don't seem to get the same mileage cruising on a flat stretch.. I think this must be because you save more fuel going downhill than you use extra going up.

Cam,


First of all my name is Nick, no biggie though. Secondly that is an interesting observation, I never thought about that before but it sounds possible.


My last tank of fuel was agressively blended and I was able to net about 19 mpg over 250 miles of highway. I have seen 20 to 21 mpg before running on #2 but not averaged for a long trip. My problem with guaging fuel consumption is that I almost always have a load, and usually pull a trailer if I'm on the highway. I drive my car when I don't need a truck, (although I would much rather drive the truck). My per tank averages vary from 14 to 18 mpg. Not too shabby for the size/weight of my rig and the kind of driving that I do. --SS

Hey Nick, Dick is the one who posted just before you, but like you said, no biggie http://www.dieselplace.com/forum/smileys/Approve.gif!


Those are some good numbers, but who drives 55? (yeah, I got the song in my head now too!)


I'm guessing that the Base line Standard is just that, a standard and for the sake of comparison. Maybe I will have to get out and try it, if I can find a road, eight miles long that is FLAT. I may have to run down to the Salt Flats to perform that test.http://www.dieselplace.com/forum/smileys/Big Smile.gif


Chris R.

I know this is going to sound dumb, but, how many miles does it take for the electronic fuel guage, "Ave. efficiency" to catchup with reality? I have just about 2000 miles on the truck and its very mixed running. Some towing (5000lb boat), mostly flat extreme stop and go traffic driving, and some highway at 65+/-. Mathematically at the end of each tank and refuel, my mileage calculates out to be higher than electronically displayed by 2-3 mpg. Also the guage will sometimes show a 0.1 mpg increase in a very short time, while at other times it takes a long time to show the same increase, and I do much the same driving every day. http://www.dieselplace.com/forum/smileys/Clown.gif

Try resetting the DIC when you refuel. Check your owners manual for details. (I love to say that!)http://www.dieselplace.com/forum/smileys/Evil Smile.gif

OOPS my bad http://www.dieselplace.com/forum/smileys/Embarrased.gif sorry Cam. --SS

No problemhttp://www.dieselplace.com/forum/smileys/Big Smile.gif


Captain Butch, I think the reason for the DIC avg. MPG going up .1's faster or slower is because the computer uses decimal points beyond a tenth of a MPG, but that's all it shows. If you park the truck one day with it showing an avg. of 15.9mpg, and the computer reads it as 15.98 for example, it won't take long at all for your DIC to jump up to 16.0. Otherwise if it had been parked at 15.91 it would take a lot longer. Make sense?





I've found my DIC to be extremely accurate.. until I started running the Juice, that is. Seems to be closer on some trucks than others.

I am constantly using my DIC to reset my instant MPG, when it drops below 30 MPG, I reset it and get back up to my 30 MPG sometimes 99.5 MPG.
http://www.dieselplace.com/forum/smileys/Clown.gif