Educate me-exhaust brake

[amsoilman]

Carlton,

I talked to my DC parts guy today, and he said the e-brake has still not been released! Do you know anything about this?





Wayne

amsoilman

 

[Dean Upson]

Casey,



Would I have to pay the GST? How many yen (Canadian) would it cost me?



Dean

 

[JWhitcomb]

dtrevathan,

Get the brake from your dealer or put it on yourself. Just don't let the dealer charge you too much. I would question anything past $850 from the dealer. No big deal to put it on yourself. Drill and tap it for EGT pyro before it is installed. Do get one as I can assure you it is money well spent. Dealer might not want to add a shifter switch but you can do that later. The trucks (manual trans. ) should come stock with them because they are that good.

 

[Carlton Bale]

Originally posted by amsoilman

I talked to my DC parts guy today, and he said the e-brake has still not been released! Do you know anything about this?

Wayne,



We shipped parts out of our Memphis facility yesterday, today, and will ship the remainder of the first order tomorrow. As soon as Mopar receives parts, the parts will go directly to dealers.



The part officially becomes active/released this Friday, Dec 20 for logistical reasons. Be assured, the first shipment of brakes are on their way!

 

[dtrevathan]

Originally posted by JWhitcomb

dtrevathan,

Get the brake from your dealer or put it on yourself. Just don't let the dealer charge you too much. I would question anything past $850 from the dealer. No big deal to put it on yourself. Drill and tap it for EGT pyro before it is installed. Do get one as I can assure you it is money well spent. Dealer might not want to add a shifter switch but you can do that later. The trucks (manual trans. ) should come stock with them because they are that good.

Thanks, I'm ordering the truck this Saturday!

 

[Steve G]

dtrevathan,

Be sure and double check with dealer. My dealer told me that it would be 2,000. + for the exhaust brake.



Steve

 

[Casey Balvert]

Bore Size

Carleton,



What is the bore size of the Jacobs exhaust brake for the new trucks? I checked the threads but could not find it anywhere.



Happy New Year,



Casey

 

[jelag]

The PacBrake exhaust brake for the new 03 is a direct mount, like it has been on the earlier trucks..... It has a 1/4" NPT port in front of the valve to test either back pressure during braking (used to test for problems) and can be used for a temp probe.....



On some exhaust brakes the back pressure can be set based on the engine model and application..... on the exhaust brake for the Cummins engine this is preset at the factory and shouldn't be tampered with..... The back pressure on the PacBrake unit has been designed by the engineers to provide the maximum back pressure suggested by Cummins for safe engine performance... .



If an engine has the ablility to make 200 HP than the brake will provide about 180 braking hp, based on engine RPM, and back pressure, when the brake is on... ... . There are several specific charts available for rating brake hp at any given RPM and back pressure... .



On this new model the throat of the elbow and the valve have been enlarged to allow for the increased HP of the new engine... Dyno tests have shown that the exhaust brake actually has less back pressure in the open position than the stock elbow... .



On the new 03, if the ECM has been designed or maybe a better word is programed to cycle the exhaust brake during cruise control operation during decent of a hill than the PacBrake will cycle if the switch is on... .



I've mentioned earlier that PacBrakes decision to use an air pump over a vacuum pump will allow the exhaust brake to function faster and with more pressure..... my personal thoughts on this is that an air compressor is from a function standpoint a better way to go.....



The pin out on the ECM allows for a signal to the ECM (pin 39 connector B) to tell the ECM that the exhaust brake is turned on...



When the ECM decides that the exhaust brake should be activated, it sends a signal (pin 42 Connector B) (actually allows a ground circuit) to the relay in the circuit to close... . when the relay closes, the solenoid in the circuit allows air to pass to the cylinder and turn on the brake.....



I think I have covered all the questions I read from the above posts..... More later if there still is more questions... .

 

[DBVZ]

Also look at the PAC Brake discussion on this forum. Same function as the Jacobs Brake, but powered by compressed air instead of a vacuum pump. To each his own, but a compressed air source on the truck may have other uses if you can tap it to keep a small tank full to air tires, etc. IMO.

 

[Balzac]

I pull a 12,000# 5er and love that PacBrake. The only other time I use it is in the winter in snow and ice, with 1,000#'s of sandbags in the box over the axle. Works great when slipery.

Jim

 

[DBVZ]

Originally posted by JWhitcomb

dtrevathan,

Get the brake from your dealer or put it on yourself. Just don't let the dealer charge you too much. I would question anything past $850 from the dealer. No big deal to put it on yourself. Drill and tap it for EGT pyro before it is installed. Do get one as I can assure you it is money well spent. Dealer might not want to add a shifter switch but you can do that later. The trucks (manual trans. ) should come stock with them because they are that good.

I think $850 was a good price for a Jacobs Brake (before rebate) for the 2G trucks. The addition of the vacuum pump added $500 to the cost, and some time to the install. The PAC Brake seems like a better option to me, since it gets you an onboard air compressor also, and seems like an easier install IMO.

 

[geusterman]

And one more burning question for Carlton: Why not use a butterfly on the intake side? It would seem less disruptive and less stressful for the engine. George

 

[jelag]

Putting a valve on the intake side would be like having a gas engine..... the intake system would be in a vacuum..... not really the effect needed to absorb power... ...



The issue with the valve in the exhaust is to create some back pressure..... on some engines thats up to 60 psi... . This back pressure is what is doing most of the work... ... .

 

[HBarlow]

I appreciate the fact that Carlton Bale, a Jacobs employee, will provide accurate factual information about his company and product on the TDR discussion list.



As many TDR members know, Cummins, the parent company of Jacobs, will also answer product specific technical questions sent to them via e-mail or by telephone. It is satisfying and refreshing to be able to speak to the manufacturer of products one owns and uses.



Cummins and Jacobs are among few large manufacturing companies who will do this. To me this reflects their corporate philosophy of appreciating and respecting their customers.



I wish more large American companies had a similar philosophy.



Thanks Cummins and Jacobs. Keep up the good work. I'm a satisfied owner of a Cummins engine and a Jacobs e-brake.



Harvey

 

[geusterman]

Thanks Jim. I knew there had to be a reason but could not figure it. More back pressure power in resisting the exhaust that in creating a vacuum. More braking in other words. Question for ya: Will the 2001 HO PacBrake fit a 2002? A TDR member has one for sale. I have emailed PacBrake a few days ago but no answer. George

 

[Oakwood]

PacMan: How is the air compressor in the Pac Brake cooled? Is it with engine oil from the Cummins?



What does the compressor weigh?



And if lthe switch in your 3500 is always left on, is the compressor always running?

 

[jelag]

The compressor is electric and has a lo / hi pressure switch that contlols the line pressure..... On the Fords were the valve is about the size of the early dodge exhaust brakes its about the size of a coffee cup... ... On the larger valve exhaust brakes where more volumn of air is needed its about the size of 2 soda cans end to end... . Its air cooled.....



My 01 had a vacuum style brake on it... ... as the vacuum pump is suitiable to power the exhaust brake... .



I have ordered some air horns, and a air tank, which I'm planning to install with one of these compressors... . In fact there at the shop but I decided to watch the rose bowl game... our team lost...



I'm guessing that sometime in the spring or early summer I'll get ride of one of our fords and purchase another new Dodge.....

 

[Carlton Bale]

Originally posted by geusterman

And one more burning question for Carlton: Why not use a butterfly on the intake side? It would seem less disruptive and less stressful for the engine. George

George,



A butterfly in the intake would provide engine retarding, just as the throttle does in a gasoline engine. One downside would be increased intake restriction with the butterfly open but this becomes less critical with a turbocharged engine.



The biggest advantage of a butterfly in the exhaust versus the intake is increased braking power. Increased backpressure during the exhaust stroke (with an exhaust brake) produces more braking power versus increased vacuum during the intake stroke (with a butterfly on the intake side. ) This is especially true with turbocharged engines -- the turbo is producing boost even during braking. This boost would make an intake throttle less effective and an exhaust throttle more effective.



Placing the butterfly in the exhaust is much more complicated from a design standpoint and can be more stressful to the engine if it is not properly implemented. An exhaust brake can cause excessive exhaust backpressure, too much exhaust valve float, excessive intake valve push tube loading, and excessive pressure on the internal turbo seals. To insure that the Cummins/Jacobs brake does not over-stress the engine in any of these ways, we've completed about 2000 hours of test cell validation under braking conditions with a full set of high speed data acquisition equipment installed. We've also installed brakes on about 60 MY03 field test trucks starting in 1999. Our top priorities are maximum engine durability as well as maximum braking horsepower. It's taken a lot of work, but we've met these objectives with the MY03 brake.

 

[geusterman]

Thanks Carlton. Because I had a PacBrake on my 8. 3 motorhome which worked well I have been wanting one for my 2002 HO, especially with the gear shift switch. How do the Jacobs and Pac Brakes stack up together? George

 

[Carlton Bale]

Originally posted by geusterman

Thanks Carlton. Because I had a PacBrake on my 8. 3 motorhome which worked well I have been wanting one for my 2002 HO, especially with the gear shift switch. How do the Jacobs and Pac Brakes stack up together? George

Having not seen a PacBrake unit, I can’t comment on how their brake compares to the Cummins/Jacobs/Mopar brake. I can tell you that we have performed an extensive amount of testing on our design to insure that there are no reliability issues with the base engine (i. e. excessive backpressure, excessive push tube loading, excessive exhaust valve float, excessive pressure drop across the turbo). We started testing the brakes on early prototype engines about 3 ½ years ago and made changes to insure we didn’t have any negative effect on engine reliability. We provide the warranty for both the engine and the brake and we’ve made sure that the two work well together.