By David Swain
ENGINE EXHAUST RETARDERS
The engine exhaust retarders absorb vehicle motion energy by not letting the engine exhaust flow out freely. By restricting the engine exhaust flow, the exhaust cycle of a piston (which should require very little energy) now becomes a compression cycle for that piston. During the exhaust cycle of the piston, the intake valves are closed and the piston is rising. Restriction of the exhaust outlet (back pressure) opposes the piston’s travel upward, and absorbs vehicle motion energy in the process.
One of the best aftermarket exhaust brake systems on the market is made by Pacbrake, a Canadian company located in British Columbia and it is available for all popular diesel pickups on the market. We installed our system on a Dodge Cummins diesel but the installation process is similar for all models.
The installation is not difficult but if you aren’t comfortable splicing into your truck’s wiring or wrestling with your exhaust system it’s a job best left for a professional who has all the right tools.
The Pacbrake kit is complete and well engineered. There are five parts for making everything work. The first is substituting the factory exhaust elbow for the Pacbrake elbow with the butterfly valve and air solenoid. The second is mounting the air compressor to the engine block. Third, installing the remote air tank and connecting the air hoses. Fourth, connecting the wiring harness and splicing into the engine ECU and transmission connectors and fifth and finally installing a switch on your dash to control the exhaust brake.
With everything ready to go, the first thing you notice when you turn the key and flip the Pacbrake exhaust switch on is that the compressor turns on and the unit cycles several times (depends on transmission type).
This ensures that the butterfly valve remains free and is not frozen due to soot or rust. On the road nothing will happen until you are above 900 RPM and our Dodge unit was designed to work with the Tow/Haul setting so that the torque converter can remain locked while decelerating to provide maximum braking effect. Once you have slowed down sufficiently, the unit releases. The Pacbrake design provides consistent braking at different rpm with their patented PRXB design. This feature provides maximum backpressure throughout the engines RPM range and provides 1/3 more retarding power than a standard exhaust brake.
Immediately after the installation we had an opportunity to test just how well the Pacbrake exhaust brake worked by going on a 1200 KM road trip that crossed the Appalachian Mountain range through West Virginia and Virginia.
There were numerous descents with 9% grades that went on for kilometers, but with the Pacbrake on we rarely had to touch the brakes, a far cry from previous trips where we had to ride rather than wonder if you’d have any brakes left at the bottom. Imagine what having a loaded trailer pushing you down the mountain would be like… yikes!
The newer diesel pickups are starting to offer exhaust brakes as an option and it is well worth it. Adding it to your existing vehicle makes even more sense, as the money you save in burning though your standard brakes, plus the peace of mind knowing you can safely stop under the most extreme conditions more than makes up for the cost of the unit.
An added bonus with the Pacbrake unit is that you can use the on board air tank to pump up a flat tire or use the air nozzle to clean something; the unit comes with a complete accessory kit in a nice travel bag.
There is also a warm-up feature that will allow the engine to come up to operating temperatures in half the time, great for our cold winters.
The bottom line is that the Pacbrake exhaust brake should be the first addition to your truck if you tow anything; it works extremely well and will save you money plus give you peace of mind.