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PacBrake C40102 PRXB Exhaust Brake for Cummins ISL 8.9L – 4" Half Marmon Turbo Flange

PacBrake C40102 PRXB Exhaust Brake for Cummins ISL 8.9L – 4" Half Marmon Turbo Flange
PacBrake C40102 PRXB Exhaust Brake for Cummins ISL 8.9L – 4" Half Marmon Turbo Flange
PacBrake C40102 PRXB Exhaust Brake for Cummins ISL 8.9L – 4" Half Marmon Turbo Flange
PacBrake C40102 PRXB Exhaust Brake for Cummins ISL 8.9L – 4" Half Marmon Turbo Flange
PacBrake C40102 PRXB Exhaust Brake for Cummins ISL 8.9L – 4" Half Marmon Turbo Flange
PacBrake C40102 PRXB Exhaust Brake for Cummins ISL 8.9L – 4" Half Marmon Turbo Flange
PacBrake C40102 PRXB Exhaust Brake for Cummins ISL 8.9L – 4" Half Marmon Turbo Flange
PacBrake C40102 PRXB Exhaust Brake for Cummins ISL 8.9L – 4" Half Marmon Turbo Flange
PacBrake C40102 PRXB Exhaust Brake for Cummins ISL 8.9L – 4" Half Marmon Turbo Flange
PacBrake C40102 PRXB Exhaust Brake for Cummins ISL 8.9L – 4" Half Marmon Turbo Flange
PacBrake C40102 PRXB Exhaust Brake for Cummins ISL 8.9L – 4" Half Marmon Turbo Flange
: C40102
In Stock(10)
$995.00
$1,297.27

PacBrake Special


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Sale ends 03/31/2026 at 11:59:59
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PacBrake C40102 PRXB Pressure Regulated Exhaust Brake for Cummins ISL 8.9L Motorhome and Truck Applications


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, you can choose when to engage the exhaust brake with just the lift of your foot from the throttle pedal. 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.

Product Benefits:

  • Provides 50 percent More Braking Power at Lower RPM's. PRXB gives you the best hold-back in the 1400-1800 RPM range (where you typically drive).
  • The spring controlled pressure regulated mechanism on the exhaust brakes protects against engine over-pressure.
  • When the brake is deactivated, exhaust flow is unrestricted and won't interfere with power output.
  • Patented 90 degree Non-contacting Butterfly Valve is specially engineered to maximize back-pressure while preventing seizing.
  • The brakes use industry exclusive Arcor nitride coating on housing and components which increases resistance to wear and corrosion while strengthening the exhaust brake and adding lubricity.

Applications:

  • Motorhomes with Cummins ISL with 4" Half Marmon Turbo

Special Notes:

  • Cummins ISL with CPL1096 must use part # C40020

Other Information:

  • Delivers the strongest braking horsepower, greatest speed reductions, and shortest stopping distances possible without the use of service brakes
  • Maintains optimum retarding performance by maximizing the exhaust backpressure throughout the entire operating RPM range
  • Delivers maximum exhaust pressure (braking) as low as 1200 RPM through to the maximum allowable engine RPM
  • Provides increased performance and peace of mind with technology that protects the engine from the potential of overpressure
  • Withstands extremely high exhaust temperatures
  • Compliant with latest emission regulations
  • Severe duty and military approved
  • No risk of engine overpressure



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Will this work on th 2016 freightliner xc Chassis with a VGT exhaust brake?

I am looking for an upgrade from the existing design to offer more braking, and i think the current one is stuck open, so looking for better options.

Thanks in advance
( Ken Dixon, 06/27/2023 )
No, these exhaust brakes are only for use with pre-2008 emissions vehicles. If you are thinking yours is "stuck open", that would mean you are having issues with the turbo or VGT controller as the engine braking is all done through the turbo itself. I would recommend having a Cummins dealer run their diagnostics on it to determine if that is the case.

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