PRXB Exhaust Brakes: Mechanics

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 a fully functional diesel exhaust brake over the entire RPM range, it is extremely important (and necessary) to maintain constant backpressure. To achieve this, Pacbrake has placed a variable orifice in the closed butterfly valve to regulate the amount of exhaust flow that is being passed through, as well as the amount that is being rejected. This flow is controlled by the arm, whose location is a result of the amount of force being placed on the spring. The spring’s 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. Every spring is pressure rated according to the vehicle application, for proper and precise braking performance.

PUTTING IT ALL TOGETHER

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

PACBRAKE'S PRXB