Upgraded to PRXB Exhaust Brake?

[OKDynasty]

Anyone upgraded their exhaust (jake) brake to the PRXB by Pac Brake? How was the install and did it make a significant difference? This would be on 2001 Dynasty Chancellor 40ft w/ tag and 370 hp Cummins ISC. Thanks,
Clarke

[WeBeGone2]

jake and pac are two different things

[OKDynasty]

Sorry,...........just call it an exhaust brake made by Pac Brake Company.
Clarke

[Diplomat Don]

Clarke......If you're looking to gain more braking at higher speeds, the PRXB won't help. It only assists with braking at lower speeds which realy isn't of much value to me.

[OKDynasty]

Don, Thanks for the reply. That's the kind of information I'm looking for . I currently have the earlier Pac Brake version. Thanks again, Clarke

[Chef Guy]

Clarke,

Upgraded my PacBrake to the PRBX last July. Wow! What a difference it makes.

As Don says, it really takes better effect at lower speeds significantly, but it also helps keep the coach at a slower speed, in a higher gear, coming down the big mountains (we live in BC, Canada and have lots of them). It will stop the coach without using the service brakes when exiting the freeway (provided the decline in slope is not too much)

It was the best $800 I have spent on this coach to date! Cannot say enough good stuff about the PRXB.

[OKDynasty]

Thanks Chef Guy!! That's what I thought / have heard it will do. Thinking about that as an upgrade before doing more mountain driving out west. Appreciate the reply and your experience,....... Clarke

[Rex]

Best price I know of (under $700) for the PXRB is here:

CLF Warehouse
1347 Terminal Street
West Sacramento, CA 95691
916-372-1447
http://www.clfwarehouse.com

[OKDynasty]

Thanks Rex. I'll give it a look. Clarke

[BigSkyBob]

I replaced my Jacobs exhaust brake with a Pacbrake PRXB almost two years ago. My old Jacobs brake was about as effective as dragging one foot on the hiway. It had about 35 PSI of exhaust back pressure and the PRXB has 60 PSI of back pressure checked with a liquid filled gauge. I checked the back pressure on a 6% grade in fourth gear @ 2300 RPM. Cummins states the back pressure for my ISL 400 should be 60 PSI so I would hesitate exceeding that specification as it might float the valves.
On Edit: I might add that on a 7% grade I have to shift to third gear for the brake to hold me back effectively.

[OKDynasty]

Thanks BigSkyBob.......................appreciate your insight and information. Clarke

[Diplomat Don]

OKDynasty......I may have come across as a jerk in my response.......didn't mean to do that. A couple of years ago I had an appointment at Quartzsite to install the PRXB (I'm willing to buy and try most anything), but as I pulled in for my appointment they were out of the model I needed. After that I went and did some research before I ordered one. After speaking to a couple of people who had them installed I learned that they were of no advantage on my coach (400ISL) for providing what I was after, more braking power from 55-65 mph. The PRXB is not designed to help at that speed.

When I descend a grade, 6% or above, my coach will continue to gain speed unless I allow the trans to shift into third gear at 44 mph with the exhaust brake on. Once I hit that 44 mph in third, my exhaust brake will hold most grades at that speed. The PRXB doesn't help at the higher speeds so it was of no interest to me.

Everyone who has one states that they really improve braking at slower speeds. Apparently the spring controlled hole in the flapper valve is what helps. It may have a different effect on your engine and coach weight, especially if you need more braking at lower speeds.

If I ever need to replace my PacBrake because of mechanical failure, I would probably buy the PRXB at that point.

[OKDynasty]

Diplomat Don, Not a problem, not a "jerk" response!! I can appreciate different / diverging viewpoints. You shared your experience and that is what I wanted. I am looking for more braking power in the lower speed ranges: 55 - 60mph and / or below,.............this coach is NO "lightweight". Thanks for clarifying your reply, I always look foward to your posts. Clarke

[Denali]

I replaced ours with the PRXB when the original failed about a year ago. After a lt of comparison shopping, I bought the new one from CLF Warehouse for $679. They drop shipped it to me direct from the Pacbrake warehouse in Seattle.

It made a significant difference. As it happens, I made several trips between CA and OR over the Siskiyou Pass on I-5 just before and just after I needed to replace the Pacbrake. On 6-7% grades I can now keep it down to 55 MPH with occasional use of the service brakes. With the original Pacbake, on those same grades I needed to keep the speed down to 45-50 MPH so the coach would stay in third gear because the Pacbrake gave virtually no braking power once I popped into fourth.

It's no Jake Brake, but it would have been well worth the expense even if the old one hadn't failed.