Pacbrake or Cummins E-brake

[Roger rodbolt]

Re: Re: Re: Pacbrake or Cummins E-brake

[Quote

Towing 21,180 GCW (21,500 GCWR) 36' 5ver with aerodynamics of a brick wall. Max EGT's in Texas summer weather running through the Hill Country - 1100 degF. Yep, that danged Jacobs brake is about to melt the engine down, I guess.



I did not say that the little hole in the Jacobs brake would melt the engine. I have towed a 5'ver, over 11,000 miles to Alaska and returned with a Jacob's brake and controlled egt's with my right foot, same as most folks do. I now do the same with my 4" remote BD brake and stage 8 injectors--but I do have to keep my towing speed below 85 if the hills are very steep . This isn't rocket science, just measure the e-brake diameter, subtract the area for the shaft and valve and chart what horsepower you wish to flow. Most folks install 4" exhaust and straight thru mufflers as they add horsepower to IMPROVE flow, but if you choose to restrict flow so be it. The 1rst Generation trucks were 160hp at the flywheel and had small exhaust (2. 75"?)with flattened bends, the 2nd Gen. trucks @160-245hp used 3" pipes and the 3rd Generation are rated up to 305hp and use 4" exhaust... ... ... ... ... ... ... ... ... ... .....

How much horsepower do you want to make or use for towing??



Big A asked in his original post which e-brake was the least restrictive when open. I'm not sure, I only know that the Jacobs '89-'02 e-brake is the most RESTRICTIVE that I've seen. Several others are less restrictive. HTH's

 

[Carlton Bale]

Originally posted by Big A

Thank you for all the info. I know that some of the brakes have better stopping power than the Cummins brake, but is too much back pressure detrimental to the engine. Carlton, did Jacobs design the new brake for the 24 valve engine, or are they basically using an old design that was meant for the 12 valve. I guess my question is, is the outlet on the Jacobs brake 2. 5" as Larry pointed out, or is it different for the 24 valve engine.

Thanks

Big A

The brake for the 2003 engine is a completely new elbow casting and butterfly designed specifically for that engine. It has a 4" connection on the inlet (turbo) side and a 3. 5" connection on the outlet (exhaust) side. This allows it to connect to the factory 3. 5" exhaust downpipe.



The increase in backpressure from the brake in the open position is very minimal and was taken into consideration during development of the engine calibration.



When closed, the exhaust brake is designed to deliver the maximum amount of braking power without causing any damage to the engine.

 

[Big A]

Re: Re: Re: Re: Pacbrake or Cummins E-brake

Big A asked in his original post which e-brake was the least restrictive when open. I'm not sure, I only know that the Jacobs '89-'02 e-brake is the most RESTRICTIVE that I've seen. Several others are less restrictive. HTH's [/B][/QUOTE]



That's correct,

Wtih that in mind, I think I'll probably still stick with the Jacobs. The BD and Pacbrake sound like a good setup,if not a better setup than the Jacobs. My only problem with the other brakes, is the fact they have not been around long compared to the Jacobs. According to the Cummins website,Jacobs uses a different brake for the 24 valve engines.

Thank You again

Big A

 

[Bill H]

I've had the Jacobs for a little over a year and no problems. Not had a Pacbrake so I cannot comment on that. Not really towed with mine yet but use it all the time with a axle switch mounted on the gear shift. If you decide to go with Jacobs, check out Mechanicsville Dodge in VA.

 

[RichB59]

I also am looking

into an exhaust brake. I want the least restrictive and adaptable one I can find. With a 4" aftermarket exhaust and the stock hy35 turbo what are my options? It looks as if the BD remote mounted would be the best. I only plan on using it in extreme condtions as I do have the auto trans. Mine is modified with the DTT pkg and smart controller but from what I understand the exh brake can still cause some increased wear ect on the auto. I had kind of a scare last year coming out of death valley into Cal down 9% grade while towing could smell the brakes cooking. Sure would like to have something to slow me down in a case like that.





RichB:--) :--)

 

[RHARVEY]

I'm not sure. . but I must have missed it. . what brake offers the best solution for an HX40 turbo???? I know that it would be some type of remote.

Sorry for the stupid question but I have sold my Pac Brake in prep. for a member of the HX40 family. I will be going with a 4" exhaust soon and I just want to know what the best options are...



Rick

 

[willyslover]

Rick. . I have the BD 4"er. . works well. . however after the crap that BD gave Piers I don't know if I would buy it again... might look at the U. S. Gear unit... [better yet call Piers and see if they are all patched up or still not doing business together].

 

[LarryB]

Originally posted by Carlton Bale





When closed, the exhaust brake is designed to deliver the maximum amount of braking power without causing any damage to the engine.

Carlton

I have noticed on long downhills under heavy (45psi) e-brake use at relatively high revs, I get white smoke out the exhaust. I'm thinking that my turbo seal is allowing oil to be pushed into the compressor side. Is this is the case, is 45psi too high or do I have a bad seal? What other damage can occur?



Thanks for your contributions to the site.

Larry

 

[Roger rodbolt]

Originally posted by Carlton Bale

The brake for the 2003 engine is a completely new elbow casting and butterfly designed specifically for that engine. It has a 4" connection on the inlet (turbo) side and a 3. 5" connection on the outlet (exhaust) side. This allows it to connect to the factory 3. 5" exhaust downpipe.

Carlton,

Thanks, that was my understanding, the 2003 e-brake is 3. 5".

Could you tell me what the elbow measurement is for the '98-2002/2nd Generation trucks? I know that it is substantially less then 3. 5" and just received a email that it was 2 3/8" smallest point. I thought that Big A was equipping his 2001 truck with an e-brake, are you suggesting that a 2003 Jacob's brake be used (or even will fit) on pre 2003 trucks or am I missing something? I apologize if Big A is wanting a 2003 model brake as I know that they are larger diameter.



RichB59 and Rick,

I think the BD 4" remote on my truck measured 4 1/4" and frankly wish that I could have purchased a 5" since I'm over 500hp and should upgrade my 4" exhaust. I changed out my Jacobs brake to install a HX 40 and since that time it has been nice experiment with other turbos/downpipes without replacing the remote e-brake. Piers told me last month that PacBrake was about to release a 4" remote brake and someone said they now have a turbo mount e-brake for the HX40. Both BD and Pacbrake have a 4" 2003 e-brakes, not sure about US Gear but I do know that their early remote brake was very compact and the early model had some service issues. Larry



I just received this article, interesting reading



http://www.usgear.com/alert.htm

 

[Carlton Bale]

Originally posted by LarryB's Super Starter Contacts

I have noticed on long downhills under heavy (45psi) e-brake use at relatively high revs, I get white smoke out the exhaust. I'm thinking that my turbo seal is allowing oil to be pushed into the compressor side. If this is the case, is 45psi too high or do I have a bad seal? What other damage can occur?

Larry,



I think you have an accurate diagnosis. The engine isn't fueling when braking so you're correct in suspecting an oil leak. The smoke is not likely coming from the power cylinder -- ring and valve stem seals would be no more likely to leak when braking. The turbo seals are a good guess; the pressure across the turbo is much different when the exhaust brake is closed. This may be causing a small amount of oil to be pushed into the compressor side of the turbo and then passed through the engine.



Possible engine problems caused by an improperly-sized exhaust brake include too much backpressure in the exhaust manifold, too much of a differential pressure across the turbo, too much exhaust valve float resulting in piston contact, and too much loading on the intake push tubes resulting in push tube bending and possibly increased cam wear.



I hope this helps solve your problem!

 

[LarryB]

Originally posted by Carlton Bale

Possible engine problems caused by an improperly-sized exhaust brake include too much backpressure in the exhaust manifold, too much of a differential pressure across the turbo,

Carlton

What max pressure has your testing shown to be acceptable?



Thanks again for your help.

 

[Carlton Bale]

Originally posted by LarryB's Super Starter Contacts

Carlton

What max pressure has your testing shown to be acceptable?



Thanks again for your help.

Larry,



Unfortunately we don't publish or advertise the max backpressure when the brake is closed. We look at a lot of dynamic performance parameters when sizing the brake -- I don't know that there is a single maximum backpressure spec that would be acceptable for all test criteria. Sorry I couldn't be of more help.

 

[LarryB]

Originally posted by Carlton Bale

Larry,



Unfortunately we don't publish or advertise the max backpressure when the brake is closed. We look at a lot of dynamic performance parameters when sizing the brake -- I don't know that there is a single maximum backpressure spec that would be acceptable for all test criteria. Sorry I couldn't be of more help.

I fully understand

Thanks!

Larry

 

[Roger rodbolt]

BD remote braking pressure

Larry,

Have you changed your internal spring or noted it's color? After setting the idle pressure I installed a permanent guage to monitor braking pressure and have played with the high pressure braking by swaping springs and shimming. I only see a puff of soot when my e-brake releases, no white smoke when engaged. Let me know if you want to adjust max pressure down.



other Larry

 

[LarryB]

Larry

My 4" BD is adjustable. I started at 25psi and worked my way up to 45. I'm now wondering if 45 is too high or I have a bad turbo seal. Maybe I'll back it off a ways. If I don't let the revs get too high on downhills it doesn't smoke but the pressure still stays at 45. Mmmm.

 

[Roger rodbolt]

Larry,

If you are adjusting the shaft to change pressures, you might try reducing the idle pressure to 20-25lbs by the threaded shaft, and add two washers under the big spring inside the brake. Not sure which number e-brake you have but BD puts different internal springs for different applications, they are color coded.

I believe that you have a motorhome and tow a trailer so it might be worth a call to BD, give them the model & serial no. for the proper spring/GVW.



LC

 

[RichB59]

Roger Rodbolt

Thanks for the article that really helps in the process of picking out the correct system. I'm glad to see putting a 4" exh on the hy35 really is helpful. After I looked at the installation 3" turbo outlet into 4" exh I wasn't so sure. I see BD makes some exh brakes for further downstream I'll be looking at those. LOL







RichB