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C40109 - Pacbrake PRXB Exhaust Brake Cummins 8.3L ISC 4" Half Marmon

C40109 - Pacbrake PRXB Exhaust Brake Cummins 8.3L ISC 4" Half Marmon

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Part # C40109 PacBrake PRXB Exhaust Brake Cummins 8.3L ISC 4" Half Marmon

Description:

Pacbrake’s flagship product, the PRXB (pressure regulated exhaust brake), is the unquestioned leader in the supplemental brake industry. The patented PRXB design delivers the strongest braking horsepower, greatest speed reductions and shortest stopping distances possible without the use of service brakes. It maintains optimum retarding performance by maximizing the exhaust backpressure throughout the entire RPM range. Unlike a typical exhaust brake, which requires high RPMs to work properly, the PRXB delivers constant exhaust pressure (braking) as early as 1200 RPM through to the maximum allowable RPM. 

Controlled by a master ON/OFF switch, Pacbrake’s exhaust brakes provide whisper quiet supplemental braking that allows service brakes to be used much less, ultimately saving you money. They have the ability to be left on all the time, making it ideal for in-city driving or for steep, downhill grades. This product pays for itself as less wear on the brake pads means fewer brake jobs.

WHAT’S SO SPECIAL ABOUT THE PRXB?
In order to have consistent and effective braking over the entire RPM range, it is important (and necessary) to maintain constant backpressure. To achieve this, Pacbrake’s patented design has incorporated an additional waste gate on the butterfly valve to regulate the amount of exhaust flow that is being passed through. The flow is controlled by a spring-loaded arm, whose pressure rating and location are key factors in the functionality of the PRXB. Located outside of the housing and away from the heat, the spring is able to maintain its strength and durability for years of proper and precise braking performance.




CREATING & MAINTAINING BACKPRESSURE
Backpressure is created by exhaust flow entering the housing, hitting the closed butterfly valve and being forced back out in the direction it came. It is maintained by the pressure-controlled spring that is located on the outside of the exhaust brake housing.

PREMIUM BRAKING PERFORMANCE
As the engine’s RPM increase, the spring compresses and the arm moves away from the butterfly valve, therefore releasing more exhaust flow through the orifice. As the RPMs decrease, the spring releases and the arm applies pressure back onto the plate, covering the hole, and ultimately releasing a smaller amount of exhaust flow.

There is less than a 10% change in backpressure over the entire RPM range on the PRXB




Features & Benefits: 

  • PRXB Delivers Strongest Braking Horsepower
  • Less Wear & Tear On Service Brakes 
  • Ideal For In-City Driving Or Steep, Downhill Grades 
Will the C40109 fit my 2006 Holliday Rambler Ambassador powered by a 8.3 Cummins diesel? Does it include the clamps and or gaskets necessary to complete the replacement. If I have to order them separate can you tell me which ones to order with cost. ( Larry Mahugh, 04/05/2021 )
Your RV will take the part # C40108 brake unit, turbo clamp part # C11355, and exhaust clamp part # C11350. ( Support )
What Pacbrake kit do I need for my 2007 T300 w/ 8.3 ISC Cummins--Allison 6 transmission-- Engine has been uprated to 310 HP
Do I need to change any valve springs?
Can you give me a quote for the parts I need to install a Pacbrake?
( Ed Werkhoven, 06/26/2020 )

Our notes indicate that you would need the following parts: C40107, C11591 and C10218. We do not see anything that would require different valve springs, that was only on the older mechanical C8.3L's.

C40107: https://www.ultrarvproducts.com/C40107-Pacbrake-PRXB-Exhaust-Brake-Cummins-8.3L-ISC-4-Full-Marmon-Cat-Flange

C11591: https://www.ultrarvproducts.com/C11591-Mounting-Group-for-Kenworth-T300

C10218: https://www.ultrarvproducts.com/C10218-Control-Group-Isb-Isc

( Support )
I currently have a jacobs exhaust brake but the actuator had failed, leaks bad and does not activate. All I need is the air actuator not the entire system. Is this something I could get through you? ( Gavin Bitz, 04/12/2020 )
I am not aware of a source for this part. I do not think the PacBrake actuator cylinder would be compatible with the Jacobs exhaust brake either. ( Support )
What all do I need for my 8.3 cummins ISC CM554 it now has a poor exhaust brake.
Will the valve train take the extra force?
I am in Canada.
Thanks for your time. John
( John Stafford, 06/25/2019 )
Yes the PRXB is designed as a direct replacement, the only engines that require modification to the valve train are the older C8.3 mechanical engines. ( Support )
Currently have a PACBrake on my ISC. PACBrake serial 098959. Which I am told is a C20384 PACbrake part number. Can I change out this older product with a new PRXB unit without any changes to the engine or transmission programming? ( Jon Tribbey, 05/19/2016 )

Jon,

Yes the PRXB brakes are designed to be direct replacement for the original style and do not require any changes to the engine or transmission.

( Support )

Would this brake valve fit the C series 8.3L cummins. Truck is an international acco 2350E

( Gavin, 07/18/2015 )

I always advise to contact PacBrake directly for fitment, their phone number is 800-663-0096.

( Support )

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WARNING: Products may contain one or more chemicals known in the State of California to cause cancer and/or birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov

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