WHAT IS A PRXB?
A PRXB is a Pressure Regulated Exhaust Brake that offers the highest retarding power for the lowest price available. Although the PRXB's retarding power is comparable to that of a compression release engine brake, the manufacturing and installation costs are significantly less.
HOW IS IT DIFFERENT FROM A STANDARD FIXED ORIFICE EXHAUST BRAKE?
Conventional exhaust brakes experience a reduced exhaust backpressure at low engine speeds, resulting in an unnecessary loss of braking power. Pacbrake's innovative PRXB addresses this issue with a patented wastegate design that regulates exhaust backpressure as engine speed changes. The valve maintains near constant engine backpressure throughout the entire RPM range, providing maximum exhaust braking power at all times.
PRXB EXHAUST BRAKE SPECIFICS
STAINLESS STEEL AIR CYLINDER:
Hard coated stainless steel cylinder and shaft with high performance seals throughout.
AUTOMATIC LOW RPM ADJUSTMENT:
Optimum retarding performance maintained by maximizing exhaust backpressure throughout the entire RPM range.
MAXIMUM ALLOWABLE EXHAUST BACKPRESSURE LIMIT:
Factory preset and designed to meet standards and requirements set by the engine manufacturer.
NO OVERPRESSURE POTENTIAL:
Enlarged oriface design.
90 DEGREE CLOSING, NON-CONTACTING BUTTERFLY VALVE:
Guarantees engine safety with special design to prevent sticking.
ARCOR NITRIDE HOUSING AND COMPONENTS:
Industry exclusive process that increases resistance to wear and corrosion, strengthens and adds lubricity.
FREE FLOW EXHAUST:
When not activated, exhaust flow is unrestricted and won't interfere with power output.
PRECISION MOUNTING SURFACE:
Both contacting surfaces are machined, which eliminates the need for gaskets.
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 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.
DIRECTMOUNT
Pacbrake's DirectMount exhaust brakes go behind the turbo in place of the exhaust elbow. It's a direct bolt-on kit that is easy to install. No fabricating for most applications. 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 degree header pipe use a cast elbow to interface with the stock header pipe. Pacbrake offers replacement header pipes for some truck models.
KIT CONTENTS
Every PRXB Automotive Kit comes with a everything required for a complete installation:
- 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 and Fittings Kit
PRXB Exhaust Brake Operation
With over a quarter of a million exhaust brakes manufactured and sold, Pacbrake has mastered quality product development. Being home to the only exhaust brake on the market with a true variable orifice, remarkable constant backpressure and strongest braking horsepower, Pacbrake has revolutionized modern day exhaust braking with its patented design of the PRXB.
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.
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 calibrated spring that is located on the outside of the exhaust brake housing. As the engine's RPM increase, the spring compresses and the arm moves away from the butterfly valve, releasing more exhaust flow through the orifice. As the RPMs decrease, the spring extends and the arm moves the plate, which covers the hole, and ultimately allows a smaller amount of exhaust flow past.
The maximum exhaust flow design accelerates the escape of gases through the wastegate which spools the turbocharger faster resulting in decreased turbo lag. In turn, this increases horsepower and torque while lowering exhaust gas temperatures. The brake's 5 bolt fl ange bolts directly to the turbocharger outlet (DirectMount design) eliminating the restrictive factory fl ange. Exhaust pipe adapters are available to fi t factory and all larger aftermarket exhaust systems.
WITH THE PRXB, THERE IS LESS THAN A 10% CHANGE IN BACKPRESSURE OVER THE ENTIRE RPM RANGE
PACBRAKE'S PRXB VS STANDARD BRAKES
With its unmatched retarding performance, the PRXB delivers constant exhaust pressure (braking) throughout the entire RPM range. Providing performance, safety and durability not seen in any other exhaust brake, the PRXB provides you with the control you need to slow your vehicle – extending your service brake life as much as 3-5 times!
Selecting the Allison transmission's tow/haul mode when reducing speed provides approximately 150 retarding horsepower. In the same mode, with the addition of a Pacbrake PRXB, the retarding ability is almost doubled, providing the most effective speed reduction possible without the need for service brakes. Allison transmissions will automatically downshift to attain higher RPM to aid in retarding, but with a Pacbrake PRXB, higher RPM is not as critical due to the unique modulation design.
Note:
All above DirectMount 2003-2007 kits will NOT work with Banks Turbo Back Monster Exhaust. However, they will work with Banks Cat Back Monster Exhaust. For applications for aftermarket turbo chargers, please contact Pacbrake for further kit information.