Pacbrake C44074 DirectMount 4-Inch PRXB High Performance Exhaust Brake Kit with Max Flow Design

The Pacbrake C44074 DirectMount PRXB Exhaust Brake Kit is a high-performance, air-actuated exhaust braking system built with Pacbrake's patented PRXB (Pressure Regulated Exhaust Brake) technology. Engineered for the Cummins 5.9L 24-valve diesel engine with a 3-inch stock exhaust and HX/HY35 turbocharger on manual transmission applications, this kit delivers the strongest supplemental braking performance available without relying on your service brakes.

Max Flow Design — Brake Smarter, Not Harder

Unlike conventional exhaust brakes, the C44074 features a Maximum Exhaust Flow Design with a unique cast housing that integrates directly to the turbocharger outlet via a 5-bolt flange, eliminating the restrictive factory flange. This design allows waste gate gases to escape faster, spooling the turbocharger more quickly to reduce turbo lag — actually increasing horsepower and torque while simultaneously lowering exhaust gas temperatures (EGTs). There is less than a 10% change in backpressure across the entire RPM range.

Key Features:

• 50% more braking power at lower RPMs — optimal holdback in the 1,400–1,800 RPM range where most driving occurs
• Patented 90-degree non-contacting butterfly valve engineered to maximize backpressure while preventing seizing
• Spring-controlled, pressure-regulated mechanism protects against engine overpressure
• Industry-exclusive Arcor nitride coating on housing and all components for superior wear and corrosion resistance
• Hard anodized aluminum body and stainless steel shaft with high-performance seals for long-term durability
• Unrestricted exhaust flow when deactivated — zero interference with power output
• DirectMount design — 5-bolt flange mounts directly to the turbocharger outlet; no additional exhaust piping required for stock exhaust
• Severe duty and military approved
• Maintenance-friendly — periodic application of Pacbrake Superlube lubricant is all that is required

What's Included:

• PRXB Exhaust Brake unit
• HP325 Series Air Compressor
• 0.5-gallon air tank
• 25-foot coiled air hose
• Air accessories and fittings kit

Optional & Required Add-Ons:

• Switch Pac: Optional — Pacbrake Part Number 18040
• ECM Bypass (C14004): Required for 1998.5 applications (sold separately)
• ECM Bypass (C12015): Optional for 1999–2002 applications
• Exhaust Adapter (C11342): Required if vehicle has a 4-inch aftermarket exhaust system

The Pacbrake PRXB is the flagship exhaust brake system trusted across automotive, vocational, and military applications — including exhaust brake systems for the U.S. Army's Stryker Wheeled Vehicle fleet. The C44074 is sold as a complete kit with everything needed for a full installation.