LML Lets talk MPG LML's

catman3126

Ehhh?.... You don't say?
Jul 24, 2012
2,636
0
36
NE Oregon
Okay so I have a later 15 LML crew cab long bed 3500HD lifted with 35's and weight with a half a tank and me with the canopy is 8300-8400 I hand calc the mpg and the dic is pretty close within a 1/2 a mpg usually. the speedo is dead on this is tuned by me with my delete tuning I have never bought or looked at anyone else's tuning (as if we could even look at them anyway) I see guys saying with Kory's tuning they can get 24 mpg at 70+. I have messed with the tuning on these more then any other year and have no complaints as to how it runs. I drive average and usually do 75 on the freeway and 65 on the hiways. I'm at 13K miles. this pickup got lifted at 700 miles. what are people really seeing hand calc with correct speedo's on these pickups? I almost want to sell a few with another tuners just to see if they can really get that good of MPG. Now I "CAN" make them read 24 on the DIC lol that's easy to do with the pulse width tables. I just can't see how a 8k+ diesel 4wd can get that good of MPG. what are people really seeing? oh and when I have towed 9500-10K on my car trailer at 70 on the freeway mine is right at around 12.5-13 if all highway.
 

iceman5

New member
Jan 19, 2016
29
0
0
Lititz, PA
I just did a highway run unloaded at 17.8 on the DIC. I haven't hand calculated it yet but so far I'm pretty close from previous fill ups.

Towing my car trailer that weighs approximately 8500 lbs, I get about 12 towing at 72 mph.

The truck is stock with the exception of the cap. It only has 2600 miles on it now so I assume that I might get better as it gets more broken in. Even if it doesn't, this is better than I was getting with my 6.0 PSD. Not really a fair comparison since it was a dually, but for me to get comparable mileage with the Ford I needed to reduce my speed to about 60.
 

WolfLMM

Making Chips
Nov 21, 2006
4,005
26
48
40
AL
Not real sure, but it ain't good:D. Made it ~170 miles with 15,000lb 40ft boat, on 30gal.:thumb:
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
23,033
8,045
113
Phoenix Az
my dads 100% stock 15.5 cc/sb GMC says 20mpg and hand calcs the same unloaded, highway driving at 70mph. towing he gets the same as me, 12.5-13mpg with the same sized load. i was actually really surprised. in town im not real sure as he dont keep track. i just do when i steal it from him every now and then :D
 

fast03

Active member
Jun 15, 2008
1,201
6
38
62
Rancho Cucamonga
Okay so I have a later 15 LML crew cab long bed 3500HD lifted with 35's and weight with a half a tank and me with the canopy is 8300-8400 I hand calc the mpg and the dic is pretty close within a 1/2 a mpg usually. the speedo is dead on this is tuned by me with my delete tuning I have never bought or looked at anyone else's tuning (as if we could even look at them anyway) I see guys saying with Kory's tuning they can get 24 mpg at 70+. I have messed with the tuning on these more then any other year and have no complaints as to how it runs. I drive average and usually do 75 on the freeway and 65 on the hiways. I'm at 13K miles. this pickup got lifted at 700 miles. what are people really seeing hand calc with correct speedo's on these pickups? I almost want to sell a few with another tuners just to see if they can really get that good of MPG. Now I "CAN" make them read 24 on the DIC lol that's easy to do with the pulse width tables. I just can't see how a 8k+ diesel 4wd can get that good of MPG. what are people really seeing? oh and when I have towed 9500-10K on my car trailer at 70 on the freeway mine is right at around 12.5-13 if all highway.

I did 70mph from So Cal to Vegas and got 20.1 mpg hand calculated

return trip Vegas>boulder city> hoover dam> Henderson> rancho Cucamonga>lax> Rancho Cucamonga plus a couple short around town trips netted me 17.9
 

catman3126

Ehhh?.... You don't say?
Jul 24, 2012
2,636
0
36
NE Oregon
my dads 100% stock 15.5 cc/sb GMC says 20mpg and hand calcs the same unloaded, highway driving at 70mph. towing he gets the same as me, 12.5-13mpg with the same sized load. i was actually really surprised. in town im not real sure as he dont keep track. i just do when i steal it from him every now and then :D

when mine was new and all stock that's close to what I got. I waseeing 18 or so for the first couple fill ups, I litterly drove it from the dealer to the shop and hooked onto a trailer with a duramax on it and it had 46 miles on it so that first fill up was off. so far I guess I'm not to far off. I think I could see 16-17 empty on the freeway if I was driving easy and on flat ground. that tank I did all freeway and got over 15 was into the wind for a 150 miles too.
 

duramaxzak

Wanna be puller!
Nov 22, 2008
2,431
14
38
Minnesota
My 11', deleted, banks intake, motor ops tuning, and 275/65/20 tires is getting around 21-22mpg in the freeway 65-70mph. Towing my gooseneck and pulling truck (appx. 13,500) I get about 13-14 on freeway. Around town empty I'm getting 16-17mpg. Before deleting it the best I could do was 17-18 on the freeway. My truck has 78k on it.

These are hand calculated, but DIC is usually within 1/2 mile/gallon.
 

catman3126

Ehhh?.... You don't say?
Jul 24, 2012
2,636
0
36
NE Oregon
Are people really going 750 miles on a tank? I've got close to 500 and that was about 15.5 and that's just letting the pump click off not filling it up to the cab like I do in my jetta. thanks to people seeing shit on the internet about getting 23-24 I'm about to the point of telling people I'm not even going to tune your duramax if you expect to see that kind of mpg. I had one guy who I tuned and deleted his 13 crew cab long bed that had a loaded down box with a fuel tank and dog boxes (sheep rancher Mike L if you want to look him up) he called and said "how come I'm not seeing 20+ with this thing (and knowing what he does with it I asked) what are you doing with it to see the 13 your getting? he well we have been towing a horse trailer around gravel roads to different pastures and up the hiway sometime's to another pasture and some freeway towing too. I want to say wtf makes you think your going to get even close to 20 doing what you are doing with that. but instead I said sounds about right to me. when I got done with that one I saw 18+ at 65 and so far my tuning is close to the DIC when hand calc.
 

catman3126

Ehhh?.... You don't say?
Jul 24, 2012
2,636
0
36
NE Oregon
My 11', deleted, banks intake, motor ops tuning, and 275/65/20 tires is getting around 21-22mpg in the freeway 65-70mph. Towing my gooseneck and pulling truck (appx. 13,500) I get about 13-14 on freeway. Around town empty I'm getting 16-17mpg. Before deleting it the best I could do was 17-18 on the freeway. My truck has 78k on it.

These are hand calculated, but DIC is usually within 1/2 mile/gallon.

This I believe! I had an 11' that I bought to test tunes and delete and that's what I was able to get in a ccsb with 275's I drove it like a car around town and I put 12K miles on it in 8 months testing tunes and building power tunes.
 

catman3126

Ehhh?.... You don't say?
Jul 24, 2012
2,636
0
36
NE Oregon
my dads 100% stock 15.5 cc/sb GMC says 20mpg and hand calcs the same unloaded, highway driving at 70mph. towing he gets the same as me, 12.5-13mpg with the same sized load. i was actually really surprised. in town im not real sure as he dont keep track. i just do when i steal it from him every now and then :D


Being that mine is lifted with mud tires running at 40 PSI I'd say 15.5 is fair now maybe if I aired them up to 60 psi I'd get better but F that its ride great this way and I'm not bitching about my mpg just what everyone else claims 20 plus on a lifted lml.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
23,033
8,045
113
Phoenix Az
Not real sure, but it ain't good:D. Made it ~170 miles with 15,000lb 40ft boat, on 30gal.:thumb:

jeezus wolf! my truck gets 10 on a bad day pulling a 15k toy hauler through the hills!!

Being that mine is lifted with mud tires running at 40 PSI I'd say 15.5 is fair now maybe if I aired them up to 60 psi I'd get better but F that its ride great this way and I'm not bitching about my mpg just what everyone else claims 20 plus on a lifted lml.

yeah i wouldnt believe it. i bet they skew the numbers. friend of ours claimed his 2014 ford f350 got 17mpg with his 35ft toy hauler loaded down with his sand car and quads. we did a trip to moab with just jeeps on flat bed trailers and he got no better than 11mpg. plus the fact he had a short bed and smaller tank ment we were stopping quite often waiting for him to fill up. needless to say, we all called his bluff :roflmao:
 

A. Stock Lbz

New member
Aug 13, 2013
342
0
0
spokane wa
My 11 lml is tuned deleted w/ 34" tires and everything else is stock. I just pulled my 35' camper to la grande oregon and got 11.2 hand calculated doing 70-80 the whole way with a little stop and go through pasco. Unloaded on the highway at 75 I get around 19-20 depending on how windy or passing people. 15 in town is the best I have done, I don't see people getting 24+ mpg out of these I think they are full of bs.
 

catman3126

Ehhh?.... You don't say?
Jul 24, 2012
2,636
0
36
NE Oregon
My 11 lml is tuned deleted w/ 34" tires and everything else is stock. I just pulled my 35' camper to la grande oregon and got 11.2 hand calculated doing 70-80 the whole way with a little stop and go through pasco. Unloaded on the highway at 75 I get around 19-20 depending on how windy or passing people. 15 in town is the best I have done, I don't see people getting 24+ mpg out of these I think they are full of bs.

Yeah they are heavy pickup also. I guess from now on I'll ask what they expect to see as for MPG and if they say something ridiculous or even 20 (depending on their setup and what they use it for) I'll just turn them away. I have reports back from most I have tuned and they see 19 or so with stock ones and 16-17 depending on wheels and tires I have a post going on the LML page on face book and I'm right on with what people are getting with other tuners. Man you went right through here lol.
 

NC-smokinlmm

<<<Future tuna killer
May 29, 2011
5,516
590
113
At Da Beach
My 11', deleted, banks intake, motor ops tuning, and 275/65/20 tires is getting around 21-22mpg in the freeway 65-70mph. Towing my gooseneck and pulling truck (appx. 13,500) I get about 13-14 on freeway. Around town empty I'm getting 16-17mpg. Before deleting it the best I could do was 17-18 on the freeway. My truck has 78k on it.

These are hand calculated, but DIC is usually within 1/2 mile/gallon.

Mines about the same, a little lower butmI'm lifted on 35's. Same tuning. I've averaged 24 a couple times over about 100 miles or so but its not easily repeatable. Conditons have to be perfect.