Official ratings of new Duramax

[KCJackson]

From the GM press release:



Duramax 6600 Provides Major Improvements In Power, Torque, and Emissions

PONTIAC, MICH. - GM's Duramax 6600 6. 6L turbo-diesel V-8 engine will provide higher power and torque ratings and major emission improvements beginning in January 2004.

Silverado and Sierra 2500HD and 3500 Series trucks with the Duramax 6600 and the Allison automatic transmission will receive a new version of the engine with 310 hp @ 3100 rpm, 10 more horsepower than before. The engine also features a higher torque rating of 590 lb-ft @ 1600 rpm, a 70 lb-ft increase over its previous maximum high. At the same time, Duramax 6600 NOx emissions have been reduced almost by half.

"Since its introduction in 2001, the Duramax 6600 has re-established GM in the full-size diesel powered truck market by increasing our share of the segment to nearly 30 percent," said Charlie Freese, executive director, diesel engineering for GM Powertrain.

Silverado and Sierra models with the Duramax 6600 and a standard ZF S6-650 six-speed manual transmission receive the same emissions improvements as those with the Allison 1000, with carryover power ratings.



In a nutshell:



Duramax/Allison: 310@3100/590@1600

Duramax/ZF: 300@3000/520@1800



Powerstroke: 325@3300/560@2000, all transmissions



Cummins: 325@2900/600@1600, all transmissions



The choice is clear

 

[KCJackson]

Another telling comment from the pres release:



"Over 90 percent of our three-quarter and one-ton customers order their Duramax 6600 with the Allison 1000 five-speed automatic transmission - prompting us to focus on power, torque and emissions improvements, where they provide greatest benefits for the largest number of customers," Freese said.



I concede Allison make a quality automatic transmission. But the ZF 6-speed is essentially the same as the one Ford uses - remember, GM passed on using the NV5600 - and GM doesn't even offer manual transmissions on any of its vans or SUVs. .

 

[Farmall Hauler]

I wonder if this may mean internal issues with the ZF transmission? It makes you wonder. The TQ numbers are much lower with the manual!



Happy holidays!



Mark

 

[Bob Beauchaine]

Gee their getting close to my '93



Bob

 

[nwjetboat]

Gee, when I was looking at trucks this summer, I was lurking on both TDR and the D-page for info. Then the "Pre-Official" Dmax numbers were going to be 310hp and 575tq. I wonder where the that extra 15 lbft came from.

Maybe it was the DC press release.

 

[DPelletier]

LOL

what a bunch of ****! " prompting us to focus... " Obviously the ZF can't take the heat.

Oh, and I also heard the dmax will defuel in first and fifth to reduce stress on thier "mighty" Allison.



Dave

 

[Rebel_Horseman]

Did the press release divulge any info about a variable output/housing turbo? When I had my Dmax, I was over at TDP and the big news was a variable turbo similar to the Ford but the housing was variable vs. the internal vanes. I'm really intrigued by the latest power wars! This reminds me of the muscle car power wars of the 60's & 70's. I remember when the '99 7. 3's came out with 500#'s and that was big time. Now, we're getting 600#'s from the factory from Cummins and almost the same from Navistar and Duramax Ltd. Talk about exciting. These trucks get better and more fun every year.



Brian [><]

 

[ACerf]

Duramax?

I wonder how really Dura the Duramax is. Given the fact that it has Aluminum Heads! That is one of the reasons I did not buy a Chevy, the other is there, off and on, electrical problems. When you look at there track record for diesel engines, it is not very impressive! Overhead that baby one time and good bye heads! This sound like another Vaga to me.

 

[Rebel_Horseman]

Aluminum Heads

When I first bought my Dmax there was all those rumors about the aluminum heads. That's a false statement. The heads are aluminum, yes, but there are 3 different gaskets between the alum heads and the cast iron block that eliminates the temperature differential. There are several members over there that have had no problems, and one member that has a trucking company has had several with well over 300k miles and no problems.



GM's problem is, or at least was, the injection system. There was a few other programming bugs, but mechanically, the injection system was a poor application, and the fuel filtration system was marginal at best.



Brian [><]

 

[Will24]

ZF needs to stick to making automatics... they make some of the best in the world but they are clueless when it comes to manuals...

 

[ACerf]

duramax

Will there could be three gaskets between the head and the block! But why would any manufacture built a Diesel with Aluminum heads in the first place. I would not trust it, Real Diesels are suppose to have Cast to Cast. The heads on a Diesel can be the weakest points. But this is GM's thinking anyway, to save a buck. As far as I am concerned the GM trucks are not built as well as the Dodge or Ford... of course I wouldn't have one of those Fix Or Repair Dailys either.

 

[Big_Daddy_T]

Mb makes cast to aluminum. We dont question them.



I will concede to being on the anti aluminum bandwagon. It worked out fine so I let it go.

 

[KCJackson]

Originally posted by Rebel_Horseman

Did the press release divulge any info about a variable output/housing turbo? When I had my Dmax, I was over at TDP and the big news was a variable turbo similar to the Ford but the housing was variable vs. the internal vanes. I'm really intrigued by the latest power wars! This reminds me of the muscle car power wars of the 60's & 70's. I remember when the '99 7. 3's came out with 500#'s and that was big time. Now, we're getting 600#'s from the factory from Cummins and almost the same from Navistar and Duramax Ltd. Talk about exciting. These trucks get better and more fun every year.



Brian [><]

Here's the part of the press release you want to know:



Primary hardware changes include a variable nozzle turbocharger, new electronic control module, next-generation fuel injectors, electronically controlled cooled exhaust gas recirculation (EGR), 50 state catalytic converter usage, improved charge air-cooling and a closed crankcase ventilation system.

 

[nickleinonen]

Originally posted by KCJackson

Here's the part of the press release you want to know:



Primary hardware changes include a variable nozzle turbocharger, new electronic control module, next-generation fuel injectors, electronically controlled cooled exhaust gas recirculation (EGR), 50 state catalytic converter usage, improved charge air-cooling and a closed crankcase ventilation system.

oh no , egr and pcv systems mixed together on a diesel do not ever work at all. look at the older 6. 2 and 6. 5 gm diesels that had both, and look at the VW tdi engines that have both... big mistake

 

[Brayden]

Some of the posters here need to realize that the GM diesels and the duramax have nothing in common. The duramax was designed by Isuzu, which is common knowledge, I thought. The aluminum head issue is NOT an issue. Plenty of the guys on thedieselpage have EGT's in the quarter mile well above 1500 degrees pre-turbo.



The MIGHTY allison is just that. . It has one of the best control systems on the planet, not to mention the transmission itself. Although the controls get in the way when you go to make more power. The computer is programmed to provide seamless shifts at a certain power level. But Drive an allison equipped vehicle and tell me it's not the smoothest shifting transmission you've ever felt.

If chevy offered the cummins, you'd all be Allison fans also.



Do you need 590 lb/ft of torque in an automatic that has a 3. 10:1 first gear ratio, not including the near 2:1 torque mulitplication of the torque convertor? Not likely. It's designed to save the transmission.



I'm not looking for flames here. . But dodge is certainly not known for their auto trannies. I wasn't about to put one in my project so I opted for a 1000 series allison, because I've been around them, built them and know the quality that goes into them.



On another note. . Allison has 80% GLOBAL market share in medium/heavy duty , on and off highway automatics. ZF is trying to compete, they actually tried to buy Allison in the early 90's. Can't beat 'em join 'em

 

[DPelletier]

Brayden,

You have some good points, and I certainly don't intend to start a war. From my perspective, I will admit that the duramax has had less issues with the aluminum heads that many (including myself) had anticipated. That having been said, I still don't like them. I think that in the long run they won't be AS durable as cast iron heads. On the other hand I had the heads replaced on my 6. 5 TD twice in 11 months and they were cast iron. As you mentioned that wasn't the current dmax made by Isuzu.

I believe the GM offerings to be slanted towards comfort and performance/weight and to be less concerned with long term durability and reliability. And before anyone chimes in with the brilliant observation that most people never keep thier trucks for 500,000 miles, therefore rendering this position invalid, these are important issues to me and many others. I may not keep my truck for 500,000 mi, but I place a high value on reliability while I do own it and I also know that I will get a very good price for the truck when I trade it in BECAUSE it will last forever. Check out the prices of used 1991 Dodge diesels vs. Ford or GM.



As far as the Allison goes, I will also admit that it is the best and probably the strongest auto transmission available in diesel pick-ups. Personally, I believe that my 6spd will likely outlast any auto, including the Allison, but there are definitely good reasonable arguments for having an auto. DC has suffered from problems with the 47RE and although the 48RE is a better unit, it still is a 4 spd and isn't exhaust brake compatible (yet).

Where I take exception to the Allison hype is when they are touting the new power ratings and fail to tell you that the powertrain is programmed to defuel in 1st and 5th. As you have stated, 1st probably isn't a big deal unless you're trying to destroy tires, but lots of us tow in OD. Therefore GM's new 590 ft lbs doesn't tell the whole story IMHO.



Sorry for the long post

Dave

 

[HEMI®Dart]

2004½ Dodge/Cummins 325/600



2004 duramax 310/590 w/ 2 more cylinders than the B5. 9?



Whats wrong with this picture?

 

[ACerf]

Duramax

I think most people, including myself knew that GM did not built the Duramax... thank god for that! It is not true that the Allision 1000 has not been with out problems. If you talk to people at Allision they will tell you that the 1000 and 2000 series are the weakest link as far as their trannys go. I drive all types of RV's that have Allision trans in them. The only really good ones are the 3000 series and above. It is true that the Dodge would be a bit better if it had the Allision. But so far I can not complain about my 48RE. It is better than the L480 or the Ford trans. It is nice to have the Allision, That is the only good thing about the GM trucks. And I still would not buy an Aluminum headed diesel... I don't care what anyone says!

 

[Brayden]

Very nice posts. Many good points. . Not much to be said... but. .



V8 vs. I6



I'm a cummins fan, so don't think I'm knocking it... The cummins has a much higher potential for torque in the lower RPM band because of it's inline configuration. The V8 diesels have a tendency to produce higher HP at higher RPM's, but less torque down low. After all HP is a function of torque and the RPM. . Not an exact equation there, but close enough. . as RPM increases HP rises and torque levels off.



Having worked at Allison's for 4 years during college, I know the products very well.



The 1K/2K/2400 series is the weakest link because it is the smallest transmission in the lineup. It is by no means an inferior product. There aren't many transmissons with 26K lb GVW ratings out there that you can get in a pickup. Yes the 3000 series (MD) is stronger, but it is much bigger, just as the 4000 series is stronger than that (HD). They all share similar designs characteristics.



Take a look at the older AT series transmissions that were produced for nearly 30 years, ending production june of '03. They're used in 1000's of applications worldwide, and have very few problems. The 1000 series is a design improvement on that transmission vocation. It has superceded it very well. You need to look at it from the OEM's standpoint, and not from a hotrodders standpoint. Everything has it's weakpoint.

 

[Hohn]

Originally posted by will24

ZF needs to stick to making automatics... they make some of the best in the world but they are clueless when it comes to autos...

HUH??