Dodge Ram 5.9L Cummins Exhaust - Better Than Stock

How to install a 4-inch after-cat exhaust

Stephen Clark
Aug 24, 2007
Photographers: Stephen Clark
Photo 2/15   |   CAG technician Chris Boyd laid out the exhaust and made sure all the parts were there before beginning to remove the stock exhaust from the truck.
Sound, performance, and style were the main factors that motivated Dan Adams to choose an MBRP Pro Series 4-inch after-cat exhaust for his '06 Dodge Ram 3500 with the 5.9L Cummins. Although Dan's Mega Cab had a 4-inch exhaust from the factory, the aftermarket kit from MBRP has several advantages over the stock exhaust. The MBRP exhaust is mandrel-bent with low-degree bends to maximize exhaust flow. This means the exhaust gases can escape from the engine easier, which lowers exhaust gas temperatures and increases horsepower, torque, and fuel mileage.
The muffler that comes with the MBRP kit is significantly smaller than the stock muffler and is much less restrictive. Also, the MBRP exhaust is manufactured from mirror-polished 304 stainless steel. This material is less susceptible to corrosion than the stock steel exhaust and will likely outlast the rest of the vehicle. Dan is a professional snowmobile rider who lives in Wyoming, and his Dodge will be driven thousands of miles on roads coated with highly corrosive salt, so stainless steel was the only was to go. As for style, MBRP hit the nail right on the head for Dan. The mirror finish looks really good, and the embossed MBRP logo on the muffler is a nice touch. To finish off the kit, Dan chose a 5-inch dual-walled exhaust tip.
We visited the guys at CAG Performance in Idaho Falls, Idaho, to witness the exhaust installation and got some tips and tricks from their master technician, Chris Boyd.
Photo 15/15   |   The total install took Chris about 40 minutes and didn't require any professional tools. Although it's easier to install an exhaust with the truck on a lift, he managed fine with a creeper on a flat concrete floor.
Keep In Mind
Dan's truck is currently running an Edge Juice module with the A2 monitor, and the MBRP exhaust has helped reduce his EGTs. Owners planning on really aggressive performance modifications-like big-horsepower electronics and injectors-would be wise to choose either a 5-inch, 6-inch, or stack exhaust system. The after-cat system does a good job of increasing performance while keeping noise levels suitable for a daily driver or tow vehicle, so it's definitely performance you can live with.


CAG Performance



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