Jacobs or Pacbrake, which is best

[mgonske]

That was my understanding too, Harvey. I'm looking forward to being somewhere that I need the warmup feature



The key factor in the imaginary operating mode would be to de-energize when the temp is up and the vehicle speed is zero.

 

[HBarlow]

Mark,



Yep, know what you mean. I made a trip down the West Coast of FL to Key West then back up the East Coast to Charleston and Virginia Beach in April.



I'm not sure the mighty Cummins even used the grid heaters to make cold starts while in your state.



Harvey

 

[Casey Balvert]

Carleton,



Has there been any progress in the testing of the brake with the 48RE transmission? My BIL just bought a new HO auto I was looking for a way to spend some of his money.



I also agree with some of the above posts. Once the engine is up to normal operating temperature it would be nice if the brake shut off at idle. Mine never shuts off, even now that we are having some warm weather. Is there any way of linking it to the clutch somehow so that it at least deactivates when the clutch is depressed?



I am really pleased with the Jacobs product so far. Thanks again for all of your input regarding the exhaust brake.



Casey

 

[Dean Upson]

Sometime ago, I think it was posted that on the trucks made after (Jan?) the Jacobs exhaust brake would shut down at a certain temp. I do not recall the exact temp, but the Cummins runs so cool at idle I doubt it would make the feature a big deal. I am pretty sure that Carlton posted something on this quite a while ago.



Dean

 

[Carlton Bale]

With regards to the E-brake shutting off, you are all correct! Here's the deal:



Model Year 2003: The E-brake turns off at coolant temps above 220 degrees F.



Model Year 2003. 5: The E-brake turns off at coolant temps above 175 degrees F. (It turns back on if coolant temp drops below 170. )



As you know, coolant temp rarely reaches 220 F, so MY03 trucks will rarely turn-off the brake at idle. This was changed for MY03. 5 to make this feature more usable.

 

[jelag]

Carlton



Could you expand on the e-brake shutting off at below the 170 degree temp... ... please qualify what conditions have to be met for this to happen... we'd expect that coolant temp must be below 170, and the speed sensor we'd assume would be at zero... . any other items... ... .



Also is there a vin or production date code where this take effect... . that is from below the 220 and 170, as you call it the 03 and 03. 5... ...



This is starting to answer some questions that I have encountered.....



Jim / Pacific Clutch

 

[Carlton Bale]

The Jacobs/Cummins manual is a little vague on the exact conditions when the brake turns off at idle. The Pac manual appears to have copied only a portion of the info from the Jacobs/Cummins manual, so I can understand all of the confusion.



It is an overly simple routine. When the engine reaches idle speed (and the throttle pedal is not depressed), the brake is turned off if coolant temperature is above 175 degrees (for MY03. 5).



If the E-brake is installed in the approved manual transmission application, this condition will only occur when the vehicle is stopped.



If the brake is installed in a (currently unapproved) automatic transmission application, the engine will return to idle long before the vehicle stops moving. This is due to the way an automatic transmission operates. Since the engine is not producing any braking power at idle conditions anyway (diesel fuel is spinning the engine), there is no need to have the exhaust brake on unless it is for the sound effect.



We are still in process of figuring out what to do for 48RE transmissions. Some test results were positive and some were negative, so I really can't give any indication at this point as to what will happen. We will not release the brake for the 48RE until there is proven reliability and a comprehensive set of users instructions so that users know exactly what is going on with their vehicle.

 

[RMcCulloch]

Carlton,



I know of one HO/48RE that DC approved the installation of a Jacobs Exhaust Brake before delivery - mine.



If some problems crop up with this combination, I'd appreciate it if you'd post something outlining the problem(s).



What, if any, are the principle differences between a J. E. B. for a manual and one for the 48RE?

 

[jelag]

Carlton



Maybe a new thread would be in order for the issues with the 48re..... would love to hear you comments... ...



Great thought RMcCulloch... Thanks



Jim

 

[Carlton Bale]

Originally posted by RMcCulloch

What, if any, are the principle differences between a J. E. B. for a manual and one for the 48RE?

There are no brake hardware differences at all. The existing E-brake kit would be the one used for 48RE applications if warranty approval were given.



I will start a thread on the 48RE/E- brake when I have something official to communicate.

 

[mgonske]

Originally posted by Carlton Bale

With regards to the E-brake shutting off, you are all correct! Here's the deal:



Model Year 2003: The E-brake turns off at coolant temps above 220 degrees F.



Model Year 2003. 5: The E-brake turns off at coolant temps above 175 degrees F. (It turns back on if coolant temp drops below 170. )



As you know, coolant temp rarely reaches 220 F, so MY03 trucks will rarely turn-off the brake at idle. This was changed for MY03. 5 to make this feature more usable.

Thanks, Carlton, that clears it up for me (and now I vaguely recall this discussion from before). Is the programming that was changed within the ECM itself? I don't suppose there's any reflash option for those of us with the 'old' '03s then?



And while we're talking (typing?), let me throw in my thanks for your participation here. I can't think of another example of an RE for a product (from a large company) engaging in this kind of direct communication with the end users!

 

[Dean Upson]

Carlton, I would like to echo what Mark just said. Thank you and Cummins.



Dean

 

[RMcCulloch]

Originally posted by Carlton Bale

There are no brake hardware differences at all. The existing E-brake kit would be the one used for 48RE applications if warranty approval were given.



I will start a thread on the 48RE/E- brake when I have something official to communicate.

Thank you!



I, for one, will truly appreciate it.



FWIW, my installation does have warranty approval [or so I've been told by the dealer].

 

[HarryWright]

pac brake

Oo. I got the pacbrake on ebay new in the box for 600. 00 and will buy air tank for better operation. The brake has a great warranty and is very well built.

 

[J&LRam]

WOW !!! Where did you dig this dead thread from???

 

[Matt400]

With regards to the E-brake shutting off, you are all correct! Here's the deal:



Model Year 2003: The E-brake turns off at coolant temps above 220 degrees F.



Model Year 2003. 5: The E-brake turns off at coolant temps above 175 degrees F. (It turns back on if coolant temp drops below 170. )



As you know, coolant temp rarely reaches 220 F, so MY03 trucks will rarely turn-off the brake at idle. This was changed for MY03. 5 to make this feature more usable.

Hi Carlton,

Sorry to re-hash this old thread but I will be installing a Jacobs Cummins part #4089427 on a 5/29/03 build date manual trans and wondered where the cut off is on your above post and if I need to consider a replacement APPS will also be needed?



Thanks

 

[Carlton Bale]

Hi Carlton,

Sorry to re-hash this old thread but I will be installing a Jacobs Cummins part #4089427 on a 5/29/03 build date manual trans and wondered where the cut off is on your above post and if I need to consider a replacement APPS will also be needed?



Thanks

Hey Matt! Based on that build date, you should have a MY03. 5. There is no APPS issue on the common rail engines (MY03 and later). That was only for a very narrow range of engines just before common rail.

 

[Matt400]

Thanks a bunch Carlton!