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I could care less what you believe

...as was noted previously...I too have a hard time with these kind of mileage reports:



not being prone to use foul language...but the word "Bullshit" does come to mind...??

80mph and youre getting 20+ mph...I dont think so sunshine.

I drive 70,000km annually...in your English that is over 50,000 miles a yr. I drive on hwys that are 90km speed limit and one is allowed by the local Police (OPP), to drive at a max of 107 km/ph. That equates to: 66.5 mph. I regularly drive 300-600km stretches at that speed.

Best I have ever gotten is 19.6 mpg...with a frickin tailwind of 10km/hr.!! That is accounting for the 265/75R16 Michelin LTX M/S Hwy hard as iron tires, MT truck, no lift, tune by Banks on level 3 (6gun PDA), Turbo Back exhaust, synthetic fluids everywhere, 2ndary fuel /oil fitlration, new filters, tayadda tayadda...blah blah blah. HAND CALCULATED.

Kindly dont blow smoke up my (_/\_) with 20-22.7 at 80mp/hr.


WE both drive 7400 lb trucks - they require a certain amount of energy to get moving and keep moving. Unless yours is made of balsa wood...is 2 inches off the ground, has a complete new body style ala Lambourghini...then yea..I call BS.!

and TIRES are the single BIGGEST Factor in getting good mileage - period. Think about it guys..?? ever try to make 30 mpg on flat tires...??

stk
It’s pretty flat going from Mobile to Texas, speed limits through work zones ranged from 55 to 70 mph. The stock tune from Steve Shelly did a remarkable job and no my truck is not made from Balsa and no I’m not blowing smoke up anyone’s ass as you put it in your reply. I have a 25 gallon tank but have never been able to add more than 22 gallons when I fuel up. The only issue I have now is my Banks de-fuels under hard acceleration due to the new tune on the ECM. Mileage in town is 16 to 17 depending on right foot. I put a set of 285 Goodrich ATR’s on last month and drove to Illinois loaded with tools and luggage, best hand calculated mileage was 20.5 at 74 cruise on and 22 at 68 cruise on. It’s funny how you join a forum like this one and give an honest report trying to help the member who posted the original question and an expert like you jumps in and calls me a bullshit artist. I don’t give a crap what you believe,what you drive or how many miles you have gone. You want to dominate the conversation so have at it steakboy it’s all yours.
 

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We get in the 20's but we are not going over 70mph, usually 60-65mph, and I try to use my foot and not cruise. I'll let the truck slow down on the hills by about 5-8 mph. and I'll keep my foot steady on the downhills and let her go up to whatever gravity gets it up to without adding pedal. I am satisfied with the mileage, after all it is a lot of truck.
 

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We get in the 20's but we are not going over 70mph, usually 60-65mph, and I try to use my foot and not cruise. I'll let the truck slow down on the hills by about 5-8 mph. and I'll keep my foot steady on the downhills and let her go up to whatever gravity gets it up to without adding pedal. I am satisfied with the mileage, after all it is a lot of truck.
D-Man, I haven’t got past the 16 to 17 in town but like you are saying in your reply 19 to 22 can be reached. I don’t know how accurate the mileage indicator is on the truck itself so everything I do lately is hand calculated. At 55 MPH, which is an impossible to drive for me unless it is a controlled speed zone that law-enforcement is going to make a buck on my numbers on the dash are pretty high but again it depends the road and how flat it is. Anytime the boost increases the mileages goes down. But I would say that overall I average a solid 21 MPG on the highway which is great. This is my first diesel…I will never go back to Gasoline. One other thing I would like to mention is I have no intension of misleading anyone with bogus numbers. I joined this forum to learn and be up-to-date on what works best on my Duramax. Take care and good talking to you.
***The tune currently on my ECM is not a live tune; the fuel mapping was reprogrammed for more power and better MPG. It did improve the turbo-lag issue by 100%. Unfortunately my Banks doesn’t like it at all. I am thinking of selling the Banks six gun/PDA and talking to Idaho Rob about a live tune for mileage and horse power. If this path leads to a dead end I will keep my setup from Steve Shelly and just sell the Banks. There has to be another tuner out there that would work for me so sooner or later I will come across that information.
 

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When the truck was bone stock on 245's I got 18 mixed (mostly highway where I am).

I then bought the Edge J/A Running that on lvl 6 with all highway I got 24 mpg keeping my speed from 63-68. (I've never matched those numbers again, and it was on Winter fuel hand calculated!)

I now have EFI live and my own tune with an S&B intake and 5" exhaust with a Diamond eye DP. I'm running 285/75's on 16x8 rims. Mixed driving will get 17-18 (again, around me there really isn't and "city" driving) On a pure highway trip keeping it between 65-70 I will get 21-22, over 70 and it drops to 20 and under pretty quick. My truck is also lowered 2".

Tires, driving style, speed, and tuning are the bigest factors in mileage.

STK, you where saying it takes a certain amount of fuel to get to and maintain a certain speed. A better way to phrase that is to say it takes a certain amount of power to get to and maintain a speed. Changing timing can get more power out of the same amount of fuel and that is where tuners can help. I beleive I can get 24-25 out of my truck with some more tuning tweaks. My truck is probably 500-600 lbs lighter then yours, and yourfront bumper probably doesn't help muchat highway speeds. If you ever get EFI live I'd be more then happy to let you try my mileage tune to see if you get over that 20-21 mpg hump.
 

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Thanks drholliday for your reply. I have a lot to learn and I’m not getting any younger. I am positive that by Jan. 2010 I will be ready to purchase the EFILive tune; I would like to study the tutorials that are out there somewhere prior to making this move. I have a buyer for my Banks if we can make the arrangements on exchanging the product for the amount agreed upon. I do not understand what all is involved or what I will need to buy to get started using the live tune. I contacted Idaho Rob for a price and possibly use him to rebuild my transmission. To my understanding there is no need to get a live tune if the Trans won’t take it. There aren’t any performance shops here in Mobile that can dyno or provide custom tunes that I know of. When I get set up on the tune I will definitely take you up on your offer to try your present tune. Are you running an additional CP3 or just the factory pump? God Bless you sir for serving your country, my Dad was also a career Marine who joined when he was 17 and turned 18 before his first Pacific Campaign, Iwo Jima. He was assigned to the 5th Marines. Stay in touch; let me know how your Duramax is running. Hard to believe a truck the size of a HD2500 can run the quarter in 12.42 and still be a daily ride. This is a great source of information to learn about diesels.
 

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Tire pressure jacked up mpg

Hey gang, just jumped my 2006 LBZ, 265/75R16 tire pressure from 55lb to 70lb. Highway mileage went from 18.1mpg @ 65mph to 19.7mpg. Tried 70mph, same test run & got 19.6mpg. I'm excited!!

Mods: Hypertech Max Energy Stage2, Rotella full-synthetic crankcase, AirRaid air induction, Aero Turbine muffler, bed cover & Deisel Kleen additive
 

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I'm averaging 17 on my LMM bone stock. I've gotten 21 on the highway, but I have always had a nack for getting the best milage out of a vehicle. Catn't wait to ditch the DPF and efitune it to see what I can get.
 

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I'm running a SC IV w/ 1054 converter.
 

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I have to agree with the adding of air pressure to boost MPG's. I have an LB7 and get about 23 to 24 when im driving to work which is 55mph the whole way. City driving or driving freeway I get about 18. But I do see about a 1 -2 mpg increase by pumping my tires from 55 to 70 psi. The adding of more air pressure also reduces the amount of sway you feel in the cab too which a plus.
 
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