# 6 liter vs duramax



## fshrs1 (Nov 20, 2009)

Looking at a GM 2500. Would like to see some real world numbers on fuel economy on the 6 liter and duramax. Thanks


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## angus242 (Oct 20, 2007)

My cousin has a Duramax 2500 4x4. He beats the living crap outta it...gas mileage be damned. He _averages_ 16.8MPG.

I have a Ford F350 6.0. I drive like I care about mileage, I average about 17.3.


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## Ninjaframer (May 28, 2011)

My diesel mechanic says if you want to get the most out of a 6.0 drive it like you stole it.


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## Chris Johnson (Apr 19, 2007)

My duramax average is 18 mpg, for $ 600.00 it can be 'reprogrammed' to 32 mpg


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## Eric K (Nov 24, 2005)

My 6.0 vans get 12mpg everywhere. Loaded - unloaded. Easy on gas - driving like a maniac. Things are like big race cars.


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## Eric K (Nov 24, 2005)

Eric K said:


> My 6.0 vans get 12mpg everywhere. Loaded - unloaded. Easy on gas - driving like a maniac. Things are like big race cars.


(gm gas motor)


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## angus242 (Oct 20, 2007)

I'm sorry, there isn't a HD truck that can get 30+MPG. Not happening. I would think 25-ish is the limit. 

It's science....


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## Eric K (Nov 24, 2005)

That is gm motor btw


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## Chris Johnson (Apr 19, 2007)

I haven't done it yet, but I have witnessed my friends 3500 which was tops 16 mpg go over 30 mpg and increase in the horsepower. It's not chipped either, they reprogram the computer.


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## Tech Dawg (Dec 13, 2010)

I gotta Duramax... can someone teach me how to reprogram for 32mpg... :laughing:

My average is around 15 but mostly driven around town... on long trips, I've tracked it as high as 21-22mpg


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## Ninjaframer (May 28, 2011)

My 6.0 does 12 to 13 in town, around 15 on mountin roads and 18 on freeway. M last truck was a dodge 1500 with a 360. Im in love with this diesel.


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## Cole82 (Nov 22, 2008)

I have never checked the milage on the diesel f450. I Think it's 15-17ish it's got really low gears in the axle.

Cole


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## NJ Brickie (Jan 31, 2009)

2004 Chevy 2500 4X4 Reg cab long bed 6.6 Duramax. Averages 17. Best ever on highway 24.


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## katoman (Apr 26, 2009)

I've got the 6 litre, six speed trans. in my 2010 one ton van. I'm typically carrying 800-1000 lbs all the time, and pulling a tandem trailer maybe 10% of the time.

I'm averaging 14.4 mpg. That's US gallons. I did the conversion.

Fantastic motor/tranny combination. It tows like a horse. Not as good as my old Dodge cummins, but it's really strong.

I would recomend this to anyone looking for a strong van. I killed my previous 3/4 ton van. It simply was not up to the tasks at hand. This new one ton is awesome.:thumbsup:


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## J L (Nov 16, 2009)

My duramax averages 16-17 mpg with mixed driving. My 6.0 gas averaged 12mpg. The duramax will pull more easier. The 6.0 seems a bit "zippier". The duramax will last twice as long and is usually paired up with the allison transmission.


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## katoman (Apr 26, 2009)

I also have the allison transmission. It comes with the 6 litre engine.

Although the diesel is stronger I'm sure, it was a $12,000 upgrade. I put on about 40,000 km. a year and will change out trucks every four years. I just couldn't justify the added cost when I'm going to trade the thing in four years.

Keep in mind, this is a work vehicle. Not my personal vehicle.


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## J L (Nov 16, 2009)

I've got 2 duramax's. I plan to run those trucks until they die. I just sold off the 6.0 as it was no longer needed - fired the project manager and eliminated the position. If I didn't plan on keeping the trucks a long time, I would have gone gas. But looking at the long run, the diesel made sense. 

Also, when I purchased my first duramax, diesel was cheaper than gas. Not so anymore :whistling


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## Leo G (May 12, 2005)

Got a 2500HD 2wd full bed, extended cab. Weighs in at 3 tons with what I carry. I get about 13.5 MPG. Drove it like a granny for the longest time, then one week I drove it like I wanted. Just about no change in mileage.


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## angus242 (Oct 20, 2007)

I"ll put the TorqShift trans up against an Allison any day.


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## Tech Dawg (Dec 13, 2010)

angus242 said:


> I"ll put the TorqShift trans up against an Allison any day.


I think you've been online too long... :laughing:


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## angus242 (Oct 20, 2007)

No way. Torqshift is the best diesel trans as far as I'm concerned.

Prove me differently.....:whistling:


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## Tech Dawg (Dec 13, 2010)

Not goin for it... Allison has auto pilot. I've already taken a nap while towing my fifthwheel... :shifty:


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## TimelessQuality (Sep 23, 2007)

My 00 2500 has the 6.0, I can get it over 15 on the highway if I'm on back roads (55-60mph). Interstate (75mph), or in town... about 13:blink:

I do love it though:thumbup:


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## blast4cash (Jan 27, 2010)

Angus you get the tow haul button with that shifts at a higher rpm and downshifts for better engine breaking.


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## Inner10 (Mar 12, 2009)

> I haven't done it yet, but I have witnessed my friends 3500 which was tops 16 mpg go over 30 mpg and increase in the horsepower. It's not chipped either, they reprogram the computer.


Chris we must have the same friend, I know a guy that claims he gets 50MPG in his Crown Vic. :laughing:

Total BS, just like how my truck is "rated" for 20/28 I'm lucky if I see 13/20.


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## woodchuck2 (Feb 27, 2008)

I used to work for GM as a tech and talked to many people about their trucks when i worked on them. A lot of friends also own the 4.8, 5.3 6.0 and 8.1's as well as the various D-Max's. I ended up buying two LBZ's to run for my business and both got 18-21mpg. Only one was tuned, air box modified and new exhaust from the turbo back. The tuned truck was tuned by PCM reflash and has gotten a best of 23mpg. 

From what i have asked from friends the 4.8 and 5.3 can average up to 18-21mpg, the older 6.0 got 10-12mpg and the 8.1 were noted for 10-13mpg. The newer 6.2 is good for up to 16mpg now but you have to baby it for that. As far as trannies all diesel's came with the Allison unless it was a van "4l80E" or was a stick. All gassers came with the 4L60E or the 4L80E unless it was the 8.1 and that came with the Allison or stick.

If you are thinking of buying the new 6.2 and are comparing it to the Duramax then gas mileage, overall price of the truck and maintenance cost will make the 6.2 very appealing. The newer Duramax's from late 07 and up have the re-generation pollution crap which literally dumps fuel in the exhaust and the the 2010 and newer have the urea injection for better fuel mileage. But the urea injection is another expense too. If you are comparing the older 6.0 to the older 2007 classic and before than IMO the D-Max is the better choice as it will get double the gas mileage of the 6.0.

Now, a diesel truck getting 30mpg :no:. The best truck out there for fuel mileage is the 24valve Cummins with a manual tranny. I have seen these trucks get 25-27mpg but you are talking about a regular cab truck driven conservatively. Each manufacturer seems to have a tuner that works well for them. I know Dodges really prefer the Smarty for power and fuel milage and the Duramax's really like the EFI-Live tuning. Honestly i have not kept up on what most Fords run but i am sure Angus can tell you.


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## J L (Nov 16, 2009)

woodchuck2 said:


> I used to work for GM as a tech and talked to many people about their trucks when i worked on them. A lot of friends also own the 4.8, 5.3 6.0 and 8.1's as well as the various D-Max's. I ended up buying two LBZ's to run for my business and both got 18-21mpg. Only one was tuned, air box modified and new exhaust from the turbo back. The tuned truck was tuned by PCM reflash and has gotten a best of 23mpg.
> 
> From what i have asked from friends the 4.8 and 5.3 can average up to 18-21mpg, the older 6.0 got 10-12mpg and the 8.1 were noted for 10-13mpg. The newer 6.2 is good for up to 16mpg now but you have to baby it for that. As far as trannies all diesel's came with the Allison unless it was a van "4l80E" or was a stick. All gassers came with the 4L60E or the 4L80E unless it was the 8.1 and that came with the Allison or stick.
> 
> ...


Good information :thumbup:


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## Joasis (Mar 28, 2006)

I miss my Duramax. 


I traded my 2003 3500 with 344k miles for a 2007 Ford 250 with a 6.0 The Chevy averaged 17 and made as high as 20....I don't think the POS Ford would get 20 if you took it up in an airplane and dropped it. I hate and despise the Ford.....I don't think I have ever regretted a vehicle purchase worse then this one...or maybe I really loved the Chevy...best truck I ever owned.


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## Ninjaframer (May 28, 2011)

Come on and tell us how you really feel, lol. 
I just bought an 06 ford with the 6.0 diesel. Although I've heard about the many problems with that engine I have to say i love this truck- maybe it's becouse it's my first diesel. I have only heard good things about the duramax though.


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## redblackviper (Oct 9, 2011)

Ninjaframer said:


> Come on and tell us how you really feel, lol.
> I just bought an 06 ford with the 6.0 diesel. Although I've heard about the many problems with that engine I have to say i love this truck- maybe it's becouse it's my first diesel. I have only heard good things about the duramax though.


First thing you Must do is get rid of the egr valve! I got a 05 f250 6.0, I upgraded my intake( banks), put a chip on it, I do 16 mpg city and 21 mpg highway with 1000 pounds loaded, since I only drive my truck loaded two hours to and from work.


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## redblackviper (Oct 9, 2011)

Oh an one more thing I have owned 3 chevys very very weak compared to the ford, I have raced on my f250 6.0 a 2010 mustang gt and I was 1 car length ahead


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## stonecutter (May 13, 2010)

Power hungry performance and dptuner lead the way with custom chips for Ford. I have a php 6 pos chip in my 7.3 and really like it so far. 

The last few years Ford used the 6.0 (06-07) were a little better than 03-05. The problem with them besides the egr is that it has inadequate head bolts leading to failure...though the people that I know that own them don't hotrod it or have a chip because it has pretty good stock power...a lot more than my 7.3.


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## stonecutter (May 13, 2010)

No way a 3/4 or 1 ton are getting 30mpg...especially now with dpf filters.

My ultimate truck would be a Ford body,interior and front end with a cummins and a john wood or allison transmission


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## redblackviper (Oct 9, 2011)

@stonecutter 
I agree that setup would be killer
Also might I point out that everyone that goes offroad on a chevy almost always changes the front arms to a straight axle


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## jomama (Oct 25, 2008)

fshrs1 said:


> Looking at a GM 2500. Would like to see some real world numbers on fuel economy on the 6 liter and duramax. Thanks


I'll only comment on what you actually asked about, and leave the Ford vs. Chevy vs. Doge crap out of it, seeing as you didn't ask about anything but a chevy in the first place.

I have an older D-max that gets about 14.5 MPG on average, but's it's hooked up to a 8K# trailer more often than not. Not to mention, it's a dually, so it's got relatively smaller tires and turns more RPMS. I've gotten as good as 17 MPG on a tank (hand calculated) in perfect conditions with 55-60 MPH highway driving empty.

A former employee has an '05 with some mild tuning done to it, and he still regularily sees 22+ MPG out of it, with mostly highway driving. Even now with it over 150K miles. The 30+ MPG will never happen on a work truck through-out the entire tank. Maybe the overhead "lie-o-meter" is fooling someone that they're getting that, but I wouldn't base a buying decision off of it.

I've also had a few 6L Chevy gas motors as well. Great motors, great power, horrible fuel milage. My current '07 gets about 12.5 with normal driving w/o a trailer. My brother has a few of them as well. The worst I witnessed was his '05 pulling his race car trailer down the highway (usually 75 MPH+), which would get about 4 MPG.

I don't think many people realize it, but there are some substantial gains to be made from having a custom tune made for a gas engine as well. I've certainly heard of 2 mpg, as well as additional HP. I plan to have mine re-burned this fall yet to try to save some fuel.

And as others have said, be cautious of buying a new deisel with all the EPA garbage. The gov. has done a fairly good job of taking the longevity of diesels, and the subsequent low maint. factor, and destroyed it. Unless you're towing fairly heavily everyday, I doubt you can recoup the additional cost of the diesel option and have it make financial logic.


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## stonecutter (May 13, 2010)

jomama said:


> I'll only comment on what you actually asked about, and leave the Ford vs. Chevy vs. Doge crap out of it, seeing as you didn't ask about anything but a chevy in the first place.
> 
> I don't think many people realize it, but there are some substantial gains to be made from having a custom tune made for a gas engine as well. I've certainly heard of 2 mpg, as well as additional HP. I plan to have mine re-burned this fall yet to try to save some fuel.
> 8
> And as others have said, be cautious of buying a new deisel with all the EPA garbage. The gov. has done a fairly good job of taking the longevity of diesels, and the subsequent low maint. factor, and destroyed it. Unless you're towing fairly heavily everyday, I doubt you can recoup the additional cost of the diesel option and have it make financial logic.


I thought the thread title said 6.0 vs duramax so it looks like a Ford and Chevy question.

Personally, I prefer Ford trucks only because that is what is familiar to me and I really like the 7.3 platform. Imo, all trucks have pros and cons and have good things to offer.

100% agree with the destruction of diesel value with epa junk on the new trucks. How would you like to replace a dpf filter at a cost of $2000? Not me...I'll take less power for a simple setup..nice straight pipe from turbo to muffler.

Php and others program chips for gassers too and are suppose to be a big improvement in mileage..I don't know numbers. I have been driving an oil burner for 12 years.


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## angus242 (Oct 20, 2007)

Nah, I think he meant Duramax vs the GM 6.0 gas engine.


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## WarnerConstInc. (Jan 30, 2008)

woodchuck2 said:


> From what i have asked from friends the 4.8 and 5.3 can average up to 18-21mpg, the older 6.0 got 10-12mpg and the 8.1 were noted for 10-13mpg. The newer 6.2 is good for up to 16mpg now but you have to baby it for that. As far as trannies all diesel's came with the Allison unless it was a van "4l80E" or was a stick.* All gassers came with the 4L60E or the 4L80E unless it was the 8.1 and that came with the Allison or stick.
> *


Except in the 3/4 ton suburbans. They could not fit the allison under the body. Which was the reason they did not offer the D-max in a suburban.

My next Burban will be one with the 8.1. I love my 454 but, the 8.1's had more ass and got a little better mileage.


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## angus242 (Oct 20, 2007)

WarnerConstInc. said:


> Except in the 3/4 ton suburbans. They could not fit the allison under the body. Which was the reason they did not offer the D-max in a suburban.
> 
> My next Burban will be one with the 8.1. I love my 454 but, the 8.1's had more ass and got a little better mileage.



Stop being such a sissy and get an Excursion with a 7.3

******* chicks dig the black smoke! :laughing:


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## stonecutter (May 13, 2010)

angus242 said:


> Nah, I think he meant Duramax vs the GM 6.0 gas engine.


Gotcha...when I see 6.0 I think navistar.


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## The Coastal Craftsman (Jun 29, 2009)

Leo G said:


> You can't compare a turbo to a normally aspirated vehicle. Stick a blower with nitrous on another truck and compare it to the ecoboost....Oh gee, not fair...


It's not fords fault everyone else is behind on motor design. It's not like it's a after market mod. It's a stock setup with TQ curves like a diesel engine and great MPG. I could go out and get the velociraptor Mod done to the 6.2 but that wouldn't count either as it's a after market mod.


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## Leo G (May 12, 2005)

Because they are two classes of engines. Turbo and non Turbo engines cannot be compared 1:1 as a fair test.

As soon as one of the other manufacturers put a turbo on an engine it will be a moot point anyway.


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## Inner10 (Mar 12, 2009)

> Because they are two classes of engines. Turbo and non Turbo engines cannot be compared 1:1 as a fair test.
> 
> As soon as one of the other manufacturers put a turbo on an engine it will be a moot point anyway.


We'll have to agree to disagree here, its a matter of if I wanted to go out and buy a half ton truck for under 40K what would I buy.

Ford just offers something different than everyone else.


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## Leo G (May 12, 2005)

BCConstruction said:


> It's not fords fault everyone else is behind on motor design. It's not like it's a after market mod. It's a stock setup with TQ curves like a diesel engine and great MPG. I could go out and get the velociraptor Mod done to the 6.2 but that wouldn't count either as it's a after market mod.


No, then it would be a fair test. Doesn't matter if it is stock or aftermarket. You compare same size engines with turbos and you have an apples to apple comparison.

If you compare a 4.3L to a 6.0L and the 6.0L kicks its azz would you consider that a fair test?


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## Inner10 (Mar 12, 2009)

> If you compare a 4.3L to a 6.0L and the 6.0L kicks its azz would you consider that a fair test?


If company A's best option was a 4.3 and company B's best option was a 6.0 in the same vehicle class then yes.


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## Leo G (May 12, 2005)

Forget it


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## The Coastal Craftsman (Jun 29, 2009)

Leo G said:


> No, then it would be a fair test. Doesn't matter if it is stock or aftermarket. You compare same size engines with turbos and you have an apples to apple comparison.
> 
> If you compare a 4.3L to a 6.0L and the 6.0L kicks its azz would you consider that a fair test?


The ecoboost was design to work like a large displacement V8 so if they did test the 3.5l v6 against a 6.0 v8 then go ahead. It will be very similar performance and if anything the ecoboost may be better because of TQ curve and MPG advantage.


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## Leo G (May 12, 2005)

I was looking around for the boost pressure that the twin turbos put on the engine so I could figure out exactly what size engine this would be comparable to. Couldn't find the pressure.

But when you do find its equal, hard takeoffs will always be the normally aspirated engines advantage, turbo lag still exists. But the turbo will eventually take over because it will have a higher torque at a lower RPM.


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## Inner10 (Mar 12, 2009)

> But when you do find its equal, hard takeoffs will always be the normally aspirated engines advantage, turbo lag still exists. But the turbo will eventually take over because it will have a higher torque at a lower RPM.


True, but I believe they are dual variable geometry turbos. Have a look at the torque curve, it pulls like a tractor at low RPM. I test drove it and was very impressed.


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## xlspecial (Sep 13, 2011)

Ecoboost is just a marketing term. It's not new technology. Many people seem to think it is.

Concerning 5.3 fuel economy. Like anything else it depends how you drive it. A friend of mine gets around 21 highway with his crew cab Silverado but drives like a grandpa. I get 16.2 overall with my Avalanche. About 18 on the interstate at 73mph.

One thing I have noticed is the ADM seems to be tuned for the EPA mileage test almost exclusively. At 55mph it drops to 4 cyl mode quite often. Anything over 60MPH and it rarely does and then only briefly unless going downhill. And I rarely run under 60 on the highway. 

btw-In tow mode it will hold 4 cyl quite a bit longer when on the highway. Try it when not towing anything and you will likely see a bump in fuel economy.

Hell, I've seen it in 4cyl mode while towing 7000 pounds, showing 15mpg on the instant mileage. Weird how it holds 4 cyl so much longer in tow mode like that.


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## Inner10 (Mar 12, 2009)

> Ecoboost is just a marketing term. It's not new technology. Many people seem to think it is.


So what other engines use direct injection and are turbocharged?


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## The Coastal Craftsman (Jun 29, 2009)

As far as I know no other cars use it because it's a new system and has not been about for years. Direct injection has been about for years but the ecoboost is not just direct injection it also turbocharged. I think people need to learn a little more about what ecoboost is as it's a proven system and has been in use for almost 5 years. 


Also turbo cars can pull away faster than NA cars. Of course as long as you have good throttle and clutch control. My mate even went as far as to add anti lag to his turbo charged engine. You should have seen the thing pull away and the noise it made. sounded like a group b rally car. But with the newer turbo designs and twin turbos it's rare to get much lag anymore. Got to admit though I love a car with a bit of turbo lag. ESP a big turbo. The way your forced back into the seat when they get upto pressure is unreal. Def not nice for day to day driving but they are fun.


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## xlspecial (Sep 13, 2011)

One example off the top of my head is the 2.0 Ecotec turbo in the 2007 Solstice GXP and Sky Red Line. Was also used in the Cobalt SS Turbo.

There are others from other manufacturers also.


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## The Coastal Craftsman (Jun 29, 2009)

xlspecial said:


> One example off the top of my head is the 2.0 Ecotec turbo in the 2007 Solstice GXP and Sky Red Line. Was also used in the Cobalt SS Turbo.
> 
> There are others from other manufacturers also.


Which was the same year the ecoboost come out! So yes it is new tech. Unless you class ecoboost as old at nearly years. Old would be fuel injected engines, ABS, turbo engines, 16 valves ect ect. Petrol Direct injection turbo engines are new.


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## Inner10 (Mar 12, 2009)

> Which was the same year the ecoboost come out! So yes it is new tech. Unless you class ecoboost as old at nearly years. Old would be fuel injected engines, ABS, turbo engines, 16 valves ect ect. Petrol Direct injection turbo engines are new.


xl has a point though, since Ford didn't start putting it in production cars until 2010.


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## WarnerConstInc. (Jan 30, 2008)

:laughing::laughing::laughing:


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## The Coastal Craftsman (Jun 29, 2009)

Inner10 said:


> xl has a point though, since Ford didn't start putting it in production cars until 2010.


I thought they was using them back in 2007/2008 because I'm sure my wifes grandma had one in her car. Thats as the first time I ever heard of ecoboost.

Just checked online and it was the concept version of her car that had it and not her car. Her model didn't have it but the year after it did.


GM let the ball drop on not developing that engine without trucks in mind.


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## Inner10 (Mar 12, 2009)

> There are others from other manufacturers also.


Ok you win:

http://en.wikipedia.org/wiki/Gasoline_direct_injection

Who would have thought it was 1925 technology?



> GM let the ball drop on not developing that engine without trucks in mind.


And every other car manufacturer since 1925. :laughing:

Once again I didn't buy it because they are a hair more powerful than a 5.7, slightly better milage, but more $ and a lot of mechanical complexity.


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## xlspecial (Sep 13, 2011)

GM has a Twin Turbo Direct Injection 3.6 V6 that is to go in the Silverado. Not sure if it is going to be available in the current model or the redesign coming for 2014. Puts out 425HP in development Camaros, but would likely be retuned for trucks.

As far as a work truck goes I wouldn't even consider an Ecoboost due to the cost. For a decked out personal truck it's fine, but when one can get a 5.3 Silverado stripper for around 20 grand the point is moot.

And, if one is going to be towing a lot you won't see a mileage improvement with it as it will always be on boost. A gas V8 or diesel (depending on tow weight) would be the choice here.

Edit-Also, GM has a 4.5 Duramax basically ready to go. Not sure why it isn't being released other than cost. THAT is an engine I would love to have in a 1/2 or 3/4 ton truck.


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## The Coastal Craftsman (Jun 29, 2009)

Inner10 said:


> Ok you win:
> 
> http://en.wikipedia.org/wiki/Gasoline_direct_injection
> 
> ...



On my next truck I'm hoping that they will have a fully electric model. They have had some concepts done with motor in each wheel would be nice and a 300-400 mile range. Not like the trucks can't hold a massive battery pack. 

direct injection has been about for a long time but just not in combination with forced induction on gasoline engines. It's been the norm for deisel for ages.


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