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PRXB exhaust brakes deliver constant backpressure throughout the entire operating RPM range for unmatched stopping power

PRXB exhaust brakes offer the highest braking power to lowest price ratio available. Pacbrake's flagship product is the unquestioned leader in the supplemental brake industry. It has changed the way people think about exhaust brakes by providing performance, safety and durability that is unmatched by any other exhaust brake on the market.

Upgrade any standard exhaust brake to a PRXB for an improved design and a longer lasting brake with significantly increased performance

Tow & haul with complete control!

PRXB Highlights

  • For the majority of diesel engines
  • Delivers the strongest braking horsepower, greatest speed reductions & 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


PRXB Features & Benefits

  • Delivers maximum backpressure throughout the entire operating RPM range
  • Withstands extremely high exhaust temperatures
  • Compliant with latest emission regulations
  • Severe duty & military approved
  • No risk of engine overpressure
  • Decreased service brake wear

PRXB Specifics

  1. STAINLESS STEEL SEALED AIR CYLINDER Hard anodized aluminum & stainless steel body & shaft with high performance seals
  2. AUTOMATIC LOW RPM ADJUSTMENT Optimum retarding performance maintained by maximizing exhaust backpressure throughout the entire operating RPM range
  3. MAXIMUM ALLOWABLE EXHAUST BACKPRESSURE LIMIT Designed & factory preset to meet standards & requirements set by the engine manufacturer
  4. NO OVERPRESSURE POTENTIAL Spring controlled, pressure regulated mechanisms
  5. 90° CLOSING, NON-CONTACTING BUTTERFLY VALVE Designed to maximize backpressure while preventing seizing
  6. ARCOR® NITRIDE HOUSING & COMPONENTS Industry exclusive process that increases resistance to wear & corrosion while strengthening & adding lubricity
  7. FREE FLOW EXHAUST When deactivated, exhaust flow is unrestricted and won’t interfere with power output
  8. PRECISION MOUNTING SURFACE Both contacting surfaces are machined, eliminating the need for troublesome gaskets

PRXB Exhaust Brake Operation

  2. ARM (Operated By Spring)
  4. ORIFICE (Hole In Butterfly Valve)
  5. WASTEGATE (Covering Orifice)
  7. BACKPRESSURE Maximum Over The Entire Operating RPM Range

Every PRXB Automotive Kit comes with everything required for a complete installation. PRXB Kits Include:

  • PRXB Exhaust Brake
  • Controller (when required for application)
  • AMP Onboard Air Kit, which includes: HP325 Series Compressor, ½ Gal Air Tank, 25ft Coiled Air Hose, Air Accessories & Fittings


Explain an InLineMount Exhaust Brake?

InLineMount – Some vehicle configurations do not allow for clearance around the turbocharger, for installation of a DirectMount exhaust brake, these applications require an InLineMount. Inline exhaust brakes require a minimum 7" of straight exhaust pipe which is then cut out and exhaust flange adapters are installed in its place. Ensure the exhaust brake is mounted as close to the turbocharger as possible and away from road spray.

NOTE: Clamped joints that exist between the brake and the engine must be welded to ensure that the joints cannot separate or leak under pressure. No flex pipe is allowed between the exhaust brake and the turbocharger.

Explain an DirectMount Exhaust Brake?

DirectMount –This application is preferred because of the reduced number of connections between the exhaust brake and the turbocharger. The mating surfaces are both machined cast iron which eliminates any chance of exhaust leaks.

For vehicles with straight back systems shortening of the header pipe is required to maintain an adequate amount of flex pipe. Vehicles with a 90° header pipe use a cast elbow to interface with the stock header pipe. Pacbrake offers replacement header pipes for some truck models.

What is a fixed orifice exhaust brake?

This is a traditional style exhaust brake tuned for maximum allowable backpressure at the maximum engine rated RPM by the drilling of a carefully selected hole size in the butterfly valve.

When should a turbo mount with a cast adapter be used?

This application is the preferred option for vehicles with a tight 90° bent header pipe post turbocharger. The cast adapter is constructed from cast iron with machined mating surfaces on both ends, eliminating any chance of exhaust leaks.

Can I change the spring in my PRXB exhaust brake to a stronger one and will it make my exhaust brake brake harder?

No, you cannot. This spring is specifically calibrated and adjusted and made tamperproof on the assembly line. This is done to ensure each application is matched to the maximum engine backpressure and will not cause any damage. Tampering with the springs will void the warranty and potentially cause severe engine damage.

What type of maintenance is needed on my exhaust brake?

The exhaust brake requires very little maintenance. If it is switched off the brake will go through an "exercise cycle" which activates the brake 3x at startup. This is to ensure it does not stick or seize up with inactive use. Also, it is recommended to apply a few drops of Pacbrake Super Lube to all pivot points every 3-6 months.

How can I tell how much back pressure my exhaust brake is producing?

Every Pacbrake exhaust brake has a 1/8" NPT port tapped into the side of the exhaust brake housing. It has a port plug threaded into it from the factory. Remove the plug and install a back pressure gauge to this port. Go for a test drive and observe the backpressure readings.

My exhaust brake comes on at idle. Why is this?

This is a normal operation if the engine is not warm. This allows the engine to warm up sooner by increasing engine load at idle. This feature can be turned off by cycling the toggle switch 8 times.

If i turn on my exhaust brake when my truck is first started, will it help to warm my engine sooner in cold weather?

Yes! This is a bonus feature of an exhaust brake. It creates a restriction at idle that puts a slight load on the engine, causing the engine to warm up faster.

Warranty Registration

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