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OT: anyone tuned their duramax for better mpg

Spud

Spud

Diamond
Joined
Jan 12, 2006
Location
Brookfield, Wisconsin
I have a 2013 Duramax, so it's the LML engine, saddled with the requirement for DEF fluid every so often.

Any experience with tuner mods to improve mpg? Right now the onboard fuel economy calculator says I get about 12-13 in the city. On the freeway I can get about 18.5 (going purely by what the computer says) if I keep it at 60 - 65 mph.
 
Spud said:
I have a 2013 Duramax, so it's the LML engine, saddled with the requirement for DEF fluid every so often.

Any experience with tuner mods to improve mpg? Right now the onboard fuel economy calculator says I get about 12-13 in the city. On the freeway I can get about 18.5 (going purely by what the computer says) if I keep it at 60 - 65 mph.
Click to expand...

Wow that sucks. you sure your calc is correct? our 2004 2500 hd duramax gets around 16-18 in the city and up to 22-23 on the freeway at anything under 70MPH thats driving from phx to flagstaff during hunting season.
I thought about a tuner on ours and said f-it never had any problems with the truck since new and it has 230k on it.
 
My 2014 Duramax gets similar numbers as Delw's . . . typically around 17-18 mpg mixed city highway driving and 21-23 mpg on the freeway. Towing numbers drop as low as 14-15 mpg with a 7500 lb trailer, down to 10-12 mpg with a 17,500 lb trailer. Bone stock with 100k miles.
 
motion guru said:
My 2014 Duramax gets similar numbers as Delw's . . . typically around 17-18 mpg mixed city highway driving and 21-23 mpg on the freeway. Towing numbers drop as low as 14-15 mpg with a 7500 lb trailer, down to 10-12 mpg with a 17,500 lb trailer. Bone stock with 100k miles.
Click to expand...

Did you go "Dune Thrashing" with yours ?.....:D
 
Delw said:
Wow that sucks. you sure your calc is correct? our 2004 2500 hd duramax gets around 16-18 in the city and up to 22-23 on the freeway at anything under 70MPH thats driving from phx to flagstaff during hunting season.
I thought about a tuner on ours and said f-it never had any problems with the truck since new and it has 230k on it.
Click to expand...

motion guru said:
My 2014 Duramax gets similar numbers as Delw's . . . typically around 17-18 mpg mixed city highway driving and 21-23 mpg on the freeway. Towing numbers drop as low as 14-15 mpg with a 7500 lb trailer, down to 10-12 mpg with a 17,500 lb trailer. Bone stock with 100k miles.
Click to expand...

The tires have an aggressive tread pattern but does the on-board mpg calculator need to be calibrated to recognize the tire's diameter?

Will post pics of the tire later today. The bull-bars must also be hurting the mpg due to increased Coefficient. of Drag ?

What size tires are you both running? Could you tell me the brand and Model # please ?
 
Your most accurate reading will be hand calculation or by using an app. If you have larger than stock tires your speedo will be off. The dic is well known to be incorrect.

Idaho Rob at adrenaline truck performance has some good dpf safe tunes, prob get an extra 2-3 mpg and you can correct your speedo.
 
I would also suggest doing the math..

I've found the mileage #'s on the on-board computers to be rather crappy..

My old lady's Jeep will show about 18mpg when we go on long trips.. But actual miles
driven divided by actual gallons burned is closer to 24.
 
Spud said:
The tires have an aggressive tread pattern but does the on-board mpg calculator need to be calibrated to recognize the tire's diameter?

Will post pics of the tire later today. The bull-bars must also be hurting the mpg due to increased Coefficient. of Drag ?

What size tires are you both running? Could you tell me the brand and Model # please ?
Click to expand...
running 26575r16 nitto terra graplers. been running them for a year and a few months and pretty happy with them. had to crank the torsion bars up a few inches in the front. handling and gas consumption is still the same. they are pretty quiet also.

My truck doesnt have a on board gas deal.
if you have big tires and a lift that will make a huge difference in gas milage ( I never thought to ask that) even on a diesel.
 
I also have a 2013 ,3500 4x4 with the Duramax /Allison package. I just got it out of the dealer's last fall ,With a leaky headgasket. It filled up the cylinder with coolant,and was pulling 750 amps on the starter motor.
The dealer fixed it under warranty [under 100,000 and under 5 yrs.] but just barely! They had it in the shop for three days before doing any work on it; They basically downloaded my onboard computer on it,Looking
really hard for any excuse to void my warranty. This was done out of the hands of the local dealer; They had to wait for permission to work on it. Took almost 3 weeks to get the truck back. Didn't cost me a dime!
Needless to say, If your still under the factory warranty, Be very careful about any Micky-Mouse tune-up
The dealer mechanic told me "that's what they were looking for" Dave [acme thread]
 
2003 duramax, get about 15-16. Thought it could do better so I got the bullydog programmer and did the level 1 program that was supposed to improve mileage. Still got 15-16mpg, but it did seem to have a bit more pep to it.
 
Yes a tuner will void the powertrain warranty. They can tell the software load dates and also by the torque reading in the computer (not sure how that works) but anything but bone stock and any engine, trans, etc repair is on you. The other parts of the warranty are not affected.
 
The powertrain , engine, ecu is all stock. The vehicle does not have DEF delete.

Specs:
2013 Chevy Silverado duramax 2500HD crew-cab 4x4 Z71 , LT trim level , short-box (6 foot box)
About 150,000 miles.


Tire info
Haida Mud terrain , all season , 33x12.50R18LT
Tire diameter : 33 "
Tire width: 10.25"
Wheel diameter : 19.25"
https://www.prioritytireoutlet.com/...-50r18-118q-e-10-ply-mt-m-t-mud-terrain-tire/

From the bottom of the frame rail at the rear to the ground is 12.5" . So I don't believe this truck is lifted. It looks to be about the same height as other similar 2500HD gas trucks in my area.

chevy-pic-1-Jan-15th-2019.jpg


chevy-pic-4-Jan-15th-2019.png
 
plastikdreams said:
Yes a tuner will void the powertrain warranty. They can tell the software load dates and also by the torque reading in the computer (not sure how that works) but anything but bone stock and any engine, trans, etc repair is on you. The other parts of the warranty are not affected.
Click to expand...

This truck has no warranty. I bought it from a dealer late 2017. Can I get warranty directly from Chevy?
 
SCT/Bully Dog Tuners Fined by the EPA for Clean Air Act Violations - Hot Rod Network

Bully Dog, et al tuners are going to jail and will be paying big, big fines. Who'd really believe some Idaho jack pine savage can find huge increases in horsepower, torque, fuel economy without any sacrifice in durability or trashing the emissions?

That would mean believing the engineers at GM, Ram, Ford are idiots and could have given customers all that good mojo but choose not to.

jack vines
 
I doubt any tuners will be going to jail. But I do agree that the big makers are already doing every last bit to get the best MPG.

So...you're driving a 7000lbs 4WD vehicle and you want good MPG....? 13 in the city is awesome, so is 18 on the highway.
 
IMO, given the tires and front add-on you are running your mileage seems to be about in the expected ballpark.
One could maybe tune one or two MPG at 62.5 on the highway at a sacrifice of around town or vice-versa.

Get efficient rolling resistance skinny tires, get rid of the thing up front, lower the truck by 4 inches....probably not what you want :).
Bob
 
Spud,
I just thought of something, does your truck have after market exhaust on it? if not it could have a restriction.if it does have and aftermarket that would be the first thing I would look at is the exhaust system.
for a stock truck thats a diesel that type of mileage doesnt sound right. my old chevy 1990 3500 1 ton(single wheel) got 12-13 in the city and under 15 on the freeway. it had 150+k on it too.

I dont know if you can get a warranty but do know that if there is any kinda update noticed( most people dont know about these)they will replace the part under main warrenty.
ours had the instrument panel changed and the injectors replaced and I just went in to the dealer for an oil change. service manager called me and said hey did you know there was a factory depault on your instrument cluster and your injectors. we will replace it at no cost. I said cool do it. it was about 8 years ago
 
A delete and tune will net much more mpg than a dpf safe tune. Along with a block or removal of the egr system I'd bet you gain 5-7 mpg. Especially if you are having more Regen cycles.
 
Delw said:
Spud,
I just thought of something, does your truck have after market exhaust on it? if not it could have a restriction.if it does have and aftermarket that would be the first thing I would look at is the exhaust system.
for a stock truck thats a diesel that type of mileage doesnt sound right. my old chevy 1990 3500 1 ton(single wheel) got 12-13 in the city and under 15 on the freeway. it had 150+k on it too.

I dont know if you can get a warranty but do know that if there is any kinda update noticed( most people dont know about these)they will replace the part under main warrenty.
ours had the instrument panel changed and the injectors replaced and I just went in to the dealer for an oil change. service manager called me and said hey did you know there was a factory depault on your instrument cluster and your injectors. we will replace it at no cost. I said cool do it. it was about 8 years ago
Click to expand...

It's the stock exhaust .

The bull-bars and rear bumpers are from RanchHand. Both together weigh around 450lbs. I bought this truck from a dealer in Forth-Worth Tx. This brand and style of bull-bars seem to be popular there. Have only seen 1 here in Wi and funny enough the truck it was on had Texas plates.

Does my truck have EGR ?
 
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