325/600 Questions

[GIT-R-DONE]

I would like to know where they got the extra 20 horsepower from for the new Cummins. What ,if any, modifications did they do to the motor and auto transmission for the 2004. 5? I did see a picture of what appeared to be some type of sensor in the turbo but don't know what it was to be sure. Did they do anything to the automatic to hold the extra power from the motor? Just thinking of trading up, but want to make sure I'm getting something that will last and be as reliable as the previous Cummins I have owned. Being cautious here. Thanks in advance



Don

 

[klenger]

Before you read any further in my reply, please understand that I know almost nothing about how diesel engines work, so I could very well be full of stuff. Keep in mind, my comments are worth what you pay for them.



Check out the power and torque curves for the 3rd gen (pre 600) engines at the link below. The curves for the HO are at the bottom of the page. Notice that the torque cureve is very flat from about 1400 to 2900 RPM. That tells me that the engine is capable of producing much more torque (which converts into HP) in this range, but is electronically limited by either the ECM or wastegate (read 1st paragraph again). It appears to me that Dodge/Cummins reworked the software to let a bit more power out. I also understand that they have reworked the exhaust sytem and that it is now 4" to the tailpipe. I assume that this is to keep EGT's lower because of the higher power (no guages). I am not aware of any changes to the drivetrain aft of the bellhousing. Dodge is probably relying on the reworked 48RE to handle the additional power, and the NV5600 is probably OK anywhay from past history of people bombing HO's in the past.



OK all you smart people, take you best shot.



http://www.cummins.com/na/pdf/en/products/dodgeram/torque_curves.pdf

 

[Matt400]

Originally posted by cuda6pack

I would like to know where they got the extra 20 horsepower from for the new Cummins. What ,if any, modifications did they do to the motor and auto transmission for the 2004. 5?

No expert here but from my research the 48RE is the same except for 2 things... 1) It will have a "tow/haul" mode to choose that will cancel OD and lock the converter and 2) it will be controlled by the Cummins engine controller rather than a DC transmission controller.

The added HP as far as I know is the 4" exhaust and software changes.

 

[DLeno]

I'll offer my thoughts as well, since we're all making inferences from what we've read



remember that the motivation for the 325/600 was primarly emissions, and then HP. very significant changes to the fuel injection event to control NOx -- there is a very late and large fuel charge I believe. The other emission related change is the oxidation catylist (soot collector).



covering both the emissions control (soot) and the HP goal is the turbocharger. there are some temp sensors there which I believe are inputs to the ECM so that it knows how to control the wastegate. I understand that the exhaust housing is a tiny bit larger. EGT control of course.



And of course support for the additional HP has to come from fuel, so they dialed up whatever fuel charge they needed to win the HP race and still meet emissions. pretty cool if you ask me -- watching the HP race. Since the 5. 9L engine itself is used in commercial applications at higher power outputs than the RAM, all they have to do to stay in the HP race is dial up whatever they need, and then make it work in the truck.



So its hard to say exactly what yielded the extra power because both the HP and emissions goals were met at the same time, with the primary changes motivated from emissions.



The interesting thing to me is the NV5600. New Venture claims this is a 550 ft lb component and (they told me personally) that they were not asked to increase the rating on it. what that tells me is that Dodge has done testing themselves and found it worthy of 600 ft lbs. not surprising; the thing is a beast, at 200 lbs more in weight than the 48RE. And consider that there are many bombed trucks out there with the 5600 running 1000 ft lbs. I have yet to hear of a bomb-related NV5600 failure (am I not paying attention?... ).



As for the 48RE, I think this puppy was designed long ago to keep pace with the HP race. my guess is that Dodge will use it without any further power handling mods, unless the new tow/haul mode mechanism is a contribution in that regard. of course, if they support an exhaust brake that means there's additional capability there, but not in the area of handling additional input torque.

 

[Rosco]

Re: Re: 325/600 Questions

Originally posted by Matt400

No expert here but from my research the 48RE is the same except for 2 things... 1) It will have a "tow/haul" mode to choose that will cancel OD and lock the converter and 2) it will be controlled by the Cummins engine controller rather than a DC transmission controller.

The added HP as far as I know is the 4" exhaust and software changes.

My 2004 Ram with the 305/555 Cummins already has the tow/haul mode instead of the "OD Off" button (same feature's though) and if I'm not mistaken all 2004 trucks use the Cummins engine controller for transmission operation.

 

[Matt400]

Re: Re: Re: 325/600 Questions

Originally posted by Rosco

My 2004 Ram with the 305/555 Cummins already has the tow/haul mode instead of the "OD Off" button (same feature's though) and if I'm not mistaken all 2004 trucks use the Cummins engine controller for transmission operation.

Interesting, I hadn't thought it was just renamed. It was my understanding that the new tow/haul mode will insure converter stays locked for exhaust brake use. I will have to do some more testing on my 03 to see if it will stay locked when the OD is switched off.

 

[Rosco]

Re: Re: Re: Re: 325/600 Questions

Originally posted by Matt400

Interesting, I hadn't thought it was just renamed. It was my understanding that the new tow/haul mode will insure converter stays locked for exhaust brake use. I will have to do some more testing on my 03 to see if it will stay locked when the OD is switched off.

I think all 48RE's regardless of model year will lock the TC in 2nd, 3rd, and overdrive. For a test try putting the gear selector in 2nd and accelerate. The transmission should make the 1-2 shift then lock the TC in second. As far as exhaust brake useage goes that still seems to be unresolved even for 04. 5 trucks.

 

[nickleinonen]

Originally posted by Rosco

I think all 48RE's regardless of model year will lock the TC in 2nd, 3rd, and overdrive. For a test try putting the gear selector in 2nd and accelerate. The transmission should make the 1-2 shift then lock the TC in second. As far as exhaust brake useage goes that still seems to be unresolved even for 04. 5 trucks.

i believe the exhaust brake will be approved for the slushbox guys on the 04. 5 models...

 

[Matt400]

Re: Re: Re: Re: Re: 325/600 Questions

Originally posted by Rosco

I think all 48RE's regardless of model year will lock the TC in 2nd, 3rd, and overdrive. For a test try putting the gear selector in 2nd and accelerate. The transmission should make the 1-2 shift then lock the TC in second. As far as exhaust brake useage goes that still seems to be unresolved even for 04. 5 trucks.

Only thing is I have noticed while in decel if you tap the brake a little you can feel the converter unlock. That would be bad news if using an exhaust brake as it would then begin to sheer the fluid in the converter. As I understood the tow/haul mode keeps the converter locked while braking. The only time I have noted lock up in 2nd was while pulling a load on a grade where after a minute or so it then locked up and I thought that was triggered by the transmission temp sensor.



As far as I know the OD switch just shuts off OD where the tow/haul switch will keep the converter locked while braking.

I will try your test... . thanks.