lml duramax mileage?

[Team208Motorsports]

Oh and BTW, mileage is calculated when you fill the tank and divide miles by gallons used, not a dash readout.

Ignorance is bliss when you have zero clue on how the GM diesels calculate fuel. Set pulse widths and commended MM with proper working speedo is going to be more accurate than remembering how many miles you started with. Now if you told me that on a gas engine I would believe it. There is a scalar I can manipulate to change how MPG is calculated. I showed the dash because any A-Hole could pull numbers out of their butt and claim 30mpg. I showed averages over periods of time, not instant. LMM and LLY are from Caldwell, ID to Boise, ID, starting at my shop and ending at my shop. LBZ is from Golconda, NV to Winnemucca, NV starting at a shop and ending at the same shop.

Remember you are not adding fuel and air to achieve stoich like a gas engine. You are adding commanded fuel, but I understand. Everyone has been burned by people that say they know what they are doing. I'll just have to apologize to all my diesel customers for their 20+ mpg rigs.

 

[82355]

There was your problem. I'm not a big fan of them, the 6.no and 6.4 are junk, the new 6.7's are good, and the old 7.3's are good for the most part, but just don't stack up to the cummins of that same late 90's era. I bought two OBS PSD's because they are cheap these days and it beats having anything gas powered around.

Wasn't mine. Beat the pants of the 7.3 I used the past two years.

Martin

 

[gonefishin]

Great info guys. Keep it coming. I think I am going to wait 2 years for my free service is over since they do the def for free. After that i will probably delete and tune it. Then i can get power and mileage

 

[Team208Motorsports]

Great info guys. Keep it coming. I think I am going to wait 2 years for my free service is over since they do the def for free. After that i will probably delete and tune it. Then i can get power and mileage

There may be a problem there. Delete will not be available legally in the US shortly. Most software will have it deactivated if you have a business within the US. Companies caught advertising will suffer a major penalty. Gotta love it when we can delete, clean tune, get better mileage.... and its illegal.

 

[rebelgregory]

Question, Team208: I hear the LML is difficult to tune. Something about an encrypted ECM or something. I also noticed you didn't post one of those in your first post. Is that true? And given the impending EPA rules, what is an LML owner to do? If we DEF-delete and tune, would it be illegal to resell down the road?

I guess that's more than one question...

 

[Team208Motorsports]

Question, Team208: I hear the LML is difficult to tune. Something about an encrypted ECM or something. I also noticed you didn't post one of those in your first post. Is that true? And given the impending EPA rules, what is an LML owner to do? If we DEF-delete and tune, would it be illegal to resell down the road?

I guess that's more than one question...

The LML is a write only ECM. So the tuner has to have a base file to work from. I have done them, just don't have any screen shots. The delete part is not as available to me for the LML.

I do not know about the re-sell info. There is still a stipulation in place about Off Road Only...... I have a feeling that will not be around much longer.

With that said. The LML can get into the high teens & low 20s in stock form but is it really that high when you have the DEF cost to account for.

Pre DEF, so LMM with DPF use the most fuel due to DPF cleaning. Fuel is the only thing there to clean it.

 

[rebelgregory]

Thanks.

Honestly, DEF is cheap and I only have to refill the tank about every 6 months so I don't really have any complaints about it. But if there is some massive amount of fuel economy or power to be had by deleting it, then I would consider it. Otherwise, I'm not the type to throw a tune at it just to commute around and occasionally tow, which is how mine gets used. I only tow about 12K lbs at most now and she doesn't have any problems doing that in stock form.

 

[miniwally]

It's pretty well established that there is tuning to be done that can both increase milage and maintain power.

I've not ever figured out why the OEM tuning isn't better.

But to the OP's question; It's my opinion that your not going to get much if anything more that 18-19 on a basic highway run with any of the big three diesel trucks in stock form. Towing is a huge variable as I have been as low as 9 mpg and as high as 15 mpg on the same stretch of highway with the same load.

Slowing down increases mileage. Some of my best has been in terrible weather in 4wd. but only going 50mph. Tires correctly inflated, correct lubricants being used etc will all help.

 

[myhichevy4x4]

As everyone said before I get 15-17 around town in my 2012 CCSB Duramax. Best tank I have seen is right around 20 with mostly highway. I just broke 25K miles and my 3 year bumper to bumper warranty expired last week. I have been looking at deletes for a while but wanted to wait until the bumper to bumper was at least expired.

Willy at Synthetic Motorsports has some of the best delete packages for the best prices that I have found. He sells complete LML delete packages using EFI Live Kory Willis tuning and then the exhaust of your choice and with or without a lift pump.

I am saving up to pull the trigger before they shut down the deletes for good.

 

[runamok151]

Exactly.....

Try running a diesel in the real world and see what actual mileage is. Best I can do with my Dodges is 14-15 in town, 17-18 on the freeway, 10 while towing lightweight (10K) and 8mpg when towing heavy (24K). My 7.3 PSD's.... forget it... my F450 that weighs 14K on it's own gets about 10mpg with no trailer.... my F350 does slightly better.

Oh and BTW, mileage is calculated when you fill the tank and divide miles by gallons used, not a dash readout.

Exactly, my trip meter read about 1.7 mpg too high when I bought the Dodge 9 years ago. It now reads about 5.2 mpg more than actual.

I've found mileage on diesels are also much more dependent on how fast you drive. Mileage in my dodge drops off real fast after 65 mph. I can get 22 mpg on the highway if I set cruise control at 65. That drops down to maybe 20 mpg at 70. 72 gives me 18 mpg.

They say your supposed to cruise at the heart of your torque curve. My Blazer gets best mileage cruising at the higher edge of it's torque peak and the Cummins seems to like the lower edge.

 

[sweetk30]

BIG FYI TO ALL : SAVE YOUR PARTS REMOVED IN DELETE JOBS .

the replacement prices are crazy and if your state does or starts emmisions testing be it tail pipe or visual or both you might wish you kept them .

my buddy got a easy 3mpg jump on his 6.7 cummins 2011 under 20k miles on it by doing the deletes . and his 1 item was dam near plugged off from crap build up ( think erg or cooler ) I don't recall exact info .

 

[Team208Motorsports]

Exactly, my trip meter read about 1.7 mpg too high when I bought the Dodge 9 years ago. It now reads about 5.2 mpg more than actual.

I've found mileage on diesels are also much more dependent on how fast you drive. Mileage in my dodge drops off real fast after 65 mph. I can get 22 mpg on the highway if I set cruise control at 65. That drops down to maybe 20 mpg at 70. 72 gives me 18 mpg.

They say your supposed to cruise at the heart of your torque curve. My Blazer gets best mileage cruising at the higher edge of it's torque peak and the Cummins seems to like the lower edge.

And thats a dodge where MPG is calculated with fuel remainder in the equation. Wouldn't be so bad if the tank scalar was linear and didn't have plateaus. Ever notice your needle will sit and move, sit and move?

Don't get me wrong. A fuel log will always be the best but thats only if your speedo is dead on and you remember to log real numbers. I have long haul guys that keep record of every drop and mile on paper, so I have a pretty good idea on whats a fudged number and what isn't. Its taken me a few years to totally dial in mileage, its there and attainable.