"If it is so good why did the newer dodge making 325/600 loose to the Duramax with 12,000 trailer attached in edmunds diesel shoot out??."

Because those are magazine idiots drag racing trucks with trailers behind them ! That tests how fast the turbo spools up and how fast the transmission shifts. Who cares about that !

The true test is put the trucks in Drive with a big trailer behind them and head for the mountains. The thing about being in Drive or OD is that the engine isn't operating at redline, its operating somewhere below and that 650 ftlbls of torque on the DM is probably seem peak value, but at the cruising speed its a lot less. Whereas the Cummins makes 600 all the time.

Pulling in Drive up hills is way different than drag racing with trailer or accelerating. I can totally see where the Cummins outpulls the new DMax.

 

Mooseguy,
Try looking at a Dyno reading for an LBZ it will reinforce your obvious lack of knowledege about the truck. Nice try though

 

There's no doubt, the duramax is a definite contender. I actually can imagine a stock duramax outpulling a stock cummins, at least for the '06 model year. If you're not gonna keep your truck absolutely forever, the gm is a viable option. I personally will always most likely prefer the cummins, but the duramax is certainly not a choice just for brainwashed brand fanatics or people who have done no research like the 6.0 is.

Myself, I just can't get past 6 cylinders inline (easy to work on by comparison), medium duty vs light duty, and idiotic durability if treated halfway decent part of the time. All generally for less money.

 

great answer v8440

i really think the inline has the dependable proven concept working for it, i have had numerious inlines on the farm and do feel this is what i need for dependabilty..... but will say our neighbor had a 903 i think it was(versatile 950 tractor) v8 cummins and that dam thing never broke down as well, pulled like a train to bout

as for both trucks running on stock hp, i think it is just a driver preference, and hp difference should not dictate the choice

but as for my personal truck, i like big power and the 5.9 can do it, but i feel the v8 can do it faster and with much less a cost, the allison is by far the choice for bigger hp

the one big reason i also disliked the cummins in 01 when i bought my first diesel, was the noise the engine created(sounded like a motor waiting to blow)..... and after sitting on the seat of a cummins tractor or combine all day, its nice to ride in peace on the way home

the tq curve of both motors are almost equal but the allison just stays within the best tq curve

 

Are you speaking of a traction dyno or an inertia dyno ? I'm guessing you have an obvious lack of knowledge about REAL trucks.

Lets say we put both trucks on a real dyno, like the ones they use for real trucks, ie road tractors. Put a small load on the dyno, like 50 HP, run the trucks up to 75 MPH and then apply a load keeping them in OD down to say 2000 RPM. Who do you think is going to pull better ? Remember that the Cummins torque curve is as flat as a pancake and your Duramax only makes its 650 at one place, down at 1600 RPM. Up at 2000 RPM your Duramax probably makes about 550 ft lbs.

Torque is what matters when pulling and torque at a reasonable pulling RPM, like 2000. Inertia dynos don't mean crap. That is why they don't test highway tractors on inertia dynos !

Nice try though !

 

Well, I wouldn't say the duramax does it at much lower cost. Though come to think of it, the duramaxes can apparently use the stock turbo to pretty high power levels now that I think about it.

Part of this depends on what you mean by really high power. If you mean 600 hp, either one can do it fairly reliably on the stock bottom end. If you mean 8 or 900 hp, from what I gather the duramax either won't stay together or must have expensive things done to the bottom end to keep it in one piece. The cummins generally does not. Note that I'm not knocking the duramax-these power levels are so far beyond the designer's intentions as to be unreasonable by most definitions. If a duramax can't often reliably take 800 hp on the stock bottom end, that's fine. If the limit was 300 hp then that would be different. The highest power trucks have 5.9 cummins in them, almost without fail. I was at Commerce, GA a few weeks ago for that mopar meet, and I saw the diesels running. There were one or two chevy trucks running a cummins. There was also a quick duramax truck running an allison. The owner was cussing it because he was having trouble keeping it together. I asked him why he continued to use it, and he told me that the class he was running in required him to use whatever came in the truck. The 1000 series allison is FAR from a perfect trans. Anyway, I'm getting off topic...

 

Lets say we put both trucks on a real dyno, like the ones they use for real trucks, ie road tractors. Put a small load on the dyno, like 50 HP, run the trucks up to 75 MPH and then apply a load keeping them in OD down to say 2000 RPM. Who do you think is going to pull better ? Remember that the Cummins torque curve is as flat as a pancake and your Duramax only makes its 650 at one place, down at 1600 RPM. Up at 2000 RPM your Duramax probably makes about 550 ft lbs.

Insults removed by Admin

 

Surely someone can come up with dyno sheets from the manufacturers (to eliminate modified trucks slipping through) so we can lay this to rest.

 

Really ? First of all a load cell measures force. I think you mean dyno cell.

Well, you do understand the difference between an inertial dyno and a chassis brake dyno, right ? Well, the Duramax builds boost faster, so it makes more power in acceleration type tests. The Cummins takes a little longer to build boost. Its not always at full boost on an inertial run, especially the stock engines and it builds revs slower. The ECM only feeds as much fuel as there is boost for. Understand ?

Now when we are on the road at 75MPH and come to a hill, the Cummins is at full boost. See the difference ?

How would you know ? Have you ever pulled a big trailer with a 3rd gen Cummins ? Maybe you've run trucks on a chassis brake dyno ?

I figure both the Duramax and the Cummins make about 600 ft lbs at 2000 RPM.

The Duramax makes 360 HP at 3200 RPM torque = HP x 5252/ RPM = 590 ft lbs, so don't tell me the Duramax has a flat torque curve. That is TOTAL BS.

To tell me the Duramax pulls better at 2000 RPM, you need to show me a torque curve. I want to see one.

My cousin has an 06 Duramax. I rode with him pulling a trailer and he rode with me. I've got a 2005 with a 6 speed. The Duramaxes use a pretty loose torque converter and it seems to slip a lot. Or his engine revs more than mine. He couldn't believe the way my Cummins just held its speed. No muss, no fuss. It just pulls.

BTW: How many commercial/industrial applications is that Duramax used in ?

You'd do well to talk a little less smack and a lot more facts.

 

Wow. That is just plain rude. In my opinion they are both good engines, and you both have a right to be all excited about things, but wow. Put them on the load dyno and see what they do, dont sit here and argue it back and forth, or post some facts, not just your personal opinion cause that isnt going to get us very far! I would take my cummins over the Dmax just for the SOUND. I dont like the Dmax, even straight piped they sound too much like a gasser. My opinion.

 

now lets see what the cummins looks like

Well here it is with 1000 miles on the clock. Let the fun begin. "06 LBZ CC Dually 4x4 Allison 6 Speed



06 LBZ duramax

now keep in mind the 07 will be stronger than this

 

First of all there is no winter fuel down here in south texas and i ran about 400 gallons thru that truck during the week. It might have been a dog not for sure but when i asked a guy who owns one after owning a dodge he said that it wont pull like a dodge. Bought an 07 on wed it had 129 miles on it took a load to Dallas and then back from Ft Worth to home ran 75 to 70 all the way. First load was low pro and weighed about 3k truck got 8.4. second load weigh around 10k adn went thru more hills truck got about 6.9 and this was with the miles under 800 for total trip. trailer weighs 8k. Went out to west Texas today and picked up a low pro load that weighed 12k and ran 70 to 80 mph. empty got 9.1 loaded i got 6.6. this mpg was the same as the dmax with 11k on it so it was broke in better and the west load was about the same area. You can look at all the numbers that these guys print out and make all the claims you want by believing what they say but i have put them in the real world and tested them by working them and can honestly say that the ctd is a better motor then the gm, because if i was impressed by the gm dont you think i would have bought one? over 96% of my trucks have been gm and i have had over 25 trucks in the last 24 yares and used to bleed bow tie blue until i started hauling with the ctd. so i would have gone gm if it would have done the job. My motto is if wasnt for the ctd motor whats the piont of owning a Dodge. thats the point i iam making not who has more bull numbers then the other and a dyno dont mean **** out on the highway trying to make a living getting the job done does

 

Fredw: that is an inertial dyno, not a chassis brake dyno. Do Duramaxes really die like that below 1800 RPM or is that because there isn't any boost yet, like I was explaining above ? Was that truck power braked to get the boost up first ? I don't know why people bother measuring these trucks on an inertial dyno when they want to compare highway pulling power.

After riding in my cousins Duramax, I totally understand what Rich is saying.

 

lets see the graph

 

I find it funny how all your cousins have Duramaxes for you to test, and your infinite wisdom is all based on drving one truck. Fredw posted the graph for the D'max lets see the one for the Cummins
Chaos, if you don't like a truck for some reason like interior, sound ride... that's fine and a valid reason. I am well aware that this is a Dodge forum, but I see no point to try and be little some one elses truck because it doesn't say Cummins. The D'max is every bit as good a puller as a Cummins, and you guys should be glad it is. Reason is simple if it wasn't for the D'max you wouldn't be getting a six speed auto or more HP/TQ. Competiton is beneficial to both sides. I'm really not a fan of my truck is better then yours. Show the edmunds pull off and the article is a rag, because Cummins didn't win, then the excuses: our truck doesn't get a chance to full boost.... If you flaw the truck by the end of first gear with a loaded trailer your manking full boost at 2900-3100rpm. Or drag racing a truck doesn't mean anything... Obviously some of you must feel this is an insult to your pride. Personally I bought my truck because it fit the bill better for a family of four and an 8 ft bed. HP/TQ were my second considerations. Anyway lets see the graph.