Project Dodge Mega Cab: Magnaflow Diesel Performance Exhaust

Nov. 22, 2010 By Jaime Hernandez
Dodge Mega Cab with 5-inch MagnaFlow Diesel Performance Exhaust

After we added the K&N FIPK II Intake on Project Dodge Mega Cab, we knew our 5.9l Cummins was breathing easier. To help the Holset Turbo along, we needed to increase the exhaust flow. 

The 5.9l HO Cummins diesel comes with a big 4-inch exhaust pipe, but we found an even bigger aftermarket system that would provide better flow and more power.

MagnaFlow Performance Mufflers feature a 100% Stainless Steel construction with Straight Trough, No Restriction flow—delivering great sound and amazing power gain.

MagnaFlow has been in the automotive aftermarket for over 30 years building catalytic converters, mufflers and complete exhaust systems with quality craftsmanship and proven power gain. If it doesn’t provide more power, they won’t make it. This has been Jerry Paolone’s policy for over 30 years.

We like that.

MagnaFlow claims to add up to 11Hp & 35ft/lb of torque on the 5.9l 24v HO Cummins; 29hp & 49ft/lb torque on 6.7l Cummins.

MagnaFlow makes their stainless steel exhaust systems in the USA, at their very own state-of-the-art ISO-9001 facility. With big names like Mario Andretti, Chip Foose, Grave Digger and Robby Gordon backing their product, you can be assured MagnaFlow is no run-of-the-mill muffler.


With diesel performance gaining popularity in the last few years, it was a natural transition for MagnaFlow to start developing performance exhaust systems for these machines.   

For the Dodge Cummins 5.9l and 6.7l, they make both cat-back and turbo back systems. The best type of system for your truck depends on your intended use (racing vs. street) and your state’s emission laws. 

MagnaFlow also offers just the muffler for those on a budget. If you can do it, go with a complete system.  The increased pipe diameter and mandrel bends will give your diesel truck a much better flow than stock.

MagnaFlow Performance diesel systems are the premium line featuring a [olished 100% stainless-steel muffler and mandrel-bent stainless steel tubing with a double wall tip. They also offer a Lifetime Warranty.

We chose to go with the MagnaFlow Series Cat-back exhaust system (Part#16955, fits 1994-2007 5.9l HO Cummins){RDhref+}id=2578

The MagnaFlow Cat-Back exhaust system is C.A.R.B. approved and will not give you a “No Pass” smog test. This is important in states like New York, Nevada, Colorado and California that regulate light-duty diesel truck emissions. 


We were lucky enough to be invited to MagnaFlow’s R&D Facility in Rancho Santa Margarita, CA where Gabe Hall, Chris Coll and crew helped tackle Project Dodge Mega Cab’s exhaust.

The MagnaFlow R&D facility is amazing. They have two dynometers on site, a lot of stainless-steel pipe, jigs and welding gear. Not to mention lifts and state-of-the-art tools that their R&D techs use to design and test new exhaust systems.

If any of you ever watched Overhaulin’ with Chip Foose (, this very building is where many of those builds were done. We were a little starstruck knowing that project Dodge Mega Cab was going to be transformed under that same roof.

Jose Cruz, the MagnaFlow maestro, was assigned to our truck. Before we could get our camera out--Jose already had the Mega Cab on the lift and removing the old pipe and muffler.

Even for Jose, a tenured muffler man, taking off the factory exhaust was a challenge. The cutting wheel and an extra pair of hands had to come out to make it happen. I’m just glad they were there to help.

The MagnaFlow Performance Exhaust installation is a simple bolt-on. The hardest part is getting the old pipe and muffler off.

Using a pneumatic cutting wheel might be necessary to allow extra wiggle room to slip the factory pipe and muffler off.

To ensure everything goes smooth, MagnaFlow creates great fitment of components and provides easy to follow instructions and a toll free number for questions (1-800-959-9226, ext.4500). Although a tree-shade mechanic could do this installation, MagnaFlow encourages having a professional do it.

Jarrod Gunn wrestles the giant boa muffler and factory pipe from our Dodge diesel truck.

The MagnaFlow system for our 5.9l Cummins featured 5-inch mandrel-bent stainless-steel tubing, a MagnaFlow muffler and 6-inch double walled tip. A big difference when compared side-by-side to the factory 4-inch steel pipe exhaust.

The cat-back exhaust system for our Dodge Mega cab included the following:

1 - Step-by-Step Instructions
1 - 4" Clamp
4 - 5" Clamp
1 - Reduced Inlet
1 - 25" Pipe
1 - MagnaFlow Muffler
1 - Tailpipe Extension
1 - Tailpipe

Since we went with the Cat Back system, a Reduced Inlet adaptor had to be used to accommodate the new 5-inch stainless steel pipe.

Getting everything lined up, Jose started slipping the stainless steel pipe together. The 25-inch pipe section in front of the muffler is used on long-bed and Mega Cab models only.

All components are mounted loosely, allowing adjustment and final fitment for clearance.  MagnFlow recommends at least 1/2" of clearance between the exhaust system and body panels to prevent heat damage or fire.

Once everything is perfectly aligned, the clamps are tightened to 65 ft-lbs. Adding a few tack welds ensure things stay put--this is especially true if you plan on using your truck off-road.

The big 6-inch double-wall exhaust tip really makes the system come together. The polished tip and engraved MagnaFlow logo give it a show quality touch.


We have logged over 1500 miles since installation. It still sounds as good as it did the first time we heard it. The truck definitely gained more power. The power estimates seem spot on for the claimed 11 hp and 35 lb-ft of increased torque.

The turbo spools up faster, giving the truck a much more quick throttle response and acceleration. EGTs are also lower.

The truck is a little louder than stock, but not obnoxious.  It’s a smooth, performance sound with the horsepower and torque to back it up.

Hear MagnaFlow Diesel Truck Exhaust

Our 5.9l Cummins is really starting to come alive--making it more fun to drive and tow with.

Overall we’re really happy with the addition. The MagnaFlow Diesel Exhaust system is amazing. It makes our truck run better and looks great too.

I would recommend anyone serious about performance and quality exhaust systems to look into MagnaFlow for diesel or gas powered engines. 

Like we stated earlier, if it doesn’t produce more power--they don’t make it.

We can live with that, and I’m sure you gear heads can too.

For MagnaFlow’s full line of Diesel Performance Exhaust visit


MagnaFlow Performance Exhaust
22961 Arroyo Vista
Rancho Santa Margarita, Ca 92688
800.824.8664 Newsletter
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