Best Exhaust For 5.9 Cummins

Off-Road Bandit TeamMar 18, '21

Built for the Dodge Ram from 2003 to 2007, the 5.9 Cummins diesel engine is an engineering marvel. By combining horsepower, torque, and fuel economy, this engine still ranks among the best diesel truck engines ever. But what if you could take it to the next level?

With better airflow and a reduction in backpressure, your truck will become an unstoppable force.

What Makes an Exhaust Worth Buying?

Exhaust systems aren’t just something to make your truck sound better. They add so much more to the equation. With improved exhaust flow, you can enhance the overall performance of your vehicle and get the most out of your 5.9 Cummins. Plus, you’ll have a few extra bonuses thrown in.

Added Performance

When exhaust exits your system more quickly, the engine fires at a more optimal rate. That translates to more horsepower and torque, as well as better fuel economy. With both 4-inch and 5-inch exhaust pipe options, you can drastically improve the overall efficiency of your 5.9 Cummins to the point of making other truck owners jealous.

Improved Appearance

Stock tailpipes are decent. But with a chrome- or black-tipped tail pipe peering out the back of your truck, you’ll add that little extra touch that makes your vehicle stand out from the pack. And with matching chrome or black aftermarket additions, you’ll have a head-turner every time you drive down the street.

Better Sound

In 2007, the EPA enacted new emissions laws for diesel-powered trucks. With all of the added emissions controls, the later-gen 6.7 Cummins just doesn’t have the same growl as the 5.9 Cummins. And by adding an aftermarket exhaust system, you can take the guttural, aggressive growl to the next level.

Review of the Best Exhausts For 5.9 Cummins

Exhaust systems for the 5.9 Cummins come in a variety of options to meet your specifics tastes, styling cues, and budget. But before you dive into the hundreds of options out there, check out these reviews of the best aftermarket exhausts money can buy.

Best Overall: MBRP 4" Cat-Back XP Series '04.5-07: S6108409


  • Easy bolt-on installation
  • Made from super durable T409 stainless steel
  • Anti-corrosive construction
  • Limited lifetime warranty
  • 4-inch pipe for excellent exhaust flow


  • Too loud for some buyers
  • Cabin drone at low RPMs

What Recent Buyers Report

The MBRP 4” Cat-Back XP Series exhaust system is one of the most highly acclaimed cat-back options for the 5.9 Cummins, according to recent buyers. With this addition, the V-6 engine sounds more like a V-8, grumbling and growling when accelerating or idling. However, the ferocious growl isn’t loved by all—some buyers report that it’s far too loud for residential neighborhoods.

Why It Stands Out to Us

With a lifetime warranty, super durable construction, and simple installation, this exhaust system checks most—if not all—of the boxes of 5.9 Cummins Ram owners. Moreover, it provides a nasty purr, giving it the final coup de grace of an excellent aftermarket exhaust system.

Bottom Line

If you want the best exhaust for a 5.9 Cummins truck, you probably won’t find a better buy than the MBRP 4” Cat-Back XP Series. It has everything a truck aficionado needs, ranging from that voracious sound to improved performance thanks to better exhaust flow.

Runner-up: MBRP 4" Turbo-Back XP Series 03-04 S6104409


  • Low, aggressive tone that appeals to many 5.9 Cummins owners
  • Lets you hear the sick whistle of your turbocharger
  • Improved fuel economy
  • Chrome exhaust tip
  • Excellent durability thanks to stainless steel construction


  • Can be difficult to install for novice DIYers
  • Expensive compared to other exhaust system options

What Recent Buyers Report

Although installation is difficult as the turbo-back exhaust goes from the turbocharger out the back, few buyers are concerned once they see the final result. After installation, the MBRP 4” Turbo-Back XP Series unleashed the beast within the 5.9 Cummins. With a healthy growl and improved performance, this exhaust system pays for itself in terms of both improved fuel economy and the glances from other Cummins enthusiasts.

Why It Stands Out to Us

Nothing harnesses every pony and foot-pound of torque quite like a turbo-back exhaust system. Once you install the system, you’ll feel every extra bit of horsepower and torque, turning your 59 Cummins into one bad mother.

Bottom Line

If you want to harness all the power of your 5.9 Cummins turbo V-6, you won’t find many better choices than the MBRP 4” Turbo-Back XP Series. However, budget-conscious buyers or those who don’t want to shell out extra money for installation may find a cat-back exhaust a more suitable alternative.

Best for the Money: MBRP 4" Cat-Back AL Series '04.5-07: S6104409


  • More affordable version of the MBRP XP Series
  • Three-year warranty
  • Anti-corrosion coating to reduce rusting
  • Easy installation process
  • Sounds great when idling and accelerating


  • Aluminized steel can corrode in extreme weather
  • Some cabin drone at certain RPMs

What Recent Buyers Report

Overall, the MBRP 4” Cat-Back AL Series delivers above expectations and at a price point that 5.9 Cummins owners will love. And while you might hear a bit of drone or hum in the cabin, buyers report that the sound from the exterior is the equivalent of aural bliss. Throw in a noticeable improvement in fuel economy, and this beast is the real deal.

Why It Stands Out to Us

Aluminized steel always sticks out as a detriment to many cat-back exhaust systems. Yet with a three-year warranty and an added anti-corrosive coating, this exhaust is ready for a true beating in terms of both weather and driving style.

Bottom Line

If you’re searching for an exhaust system that provides a trifecta of improved mileage, better torque, and excellent sound, the MBRP 4” Cat-Back AL Series delivers where you need it most. However, harsher climates can take their toll, even with an anti-corrosion coating. As a result, owners that live in rainy or wintry areas may want to opt for the MBRP XP Series, as it uses more durable stainless steel.

Editor's Pick: MBRP 5" Turbo-Back Performance Series '98-02: S61120P


  • Bigger 5-inch pipes improve exhaust flow
  • More aggressive sound over stock exhaust/muffler
  • Turbo-back gets the most out of your 5.9 Cummins
  • Easy to install
  • Made from coated aluminized steel to prevent rust


  • Only a one-year warranty
  • Made need modifications for installation

What Recent Buyers Report

Buyers report that the MBRP 5” Turbo-Back Performance Series exhaust series provides a notable boost to torque, horsepower, and fuel economy. However, some also state that it requires some modifications and maybe even welding to correctly fit into place.

Why It Stands Out to Us

If you’re searching for less backpressure and improved exhaust flow, the 5-inch pipes on this exhaust system are sure to meet your expectations and beyond. And with a turbo-back design, you can get every bit of horsepower and torque from your 5.9 Cummins diesel engine.

Bottom Line

Although it may not offer the same durability and longevity as the XP or AL series, the MBRP 5” Turbo-Back Performance Series exhaust should still meet the approval of most 5.9 Cummins owners. Those that want a bit of extra performance or a deeper growl may want to consider the higher-grade of MBRP products.

Honorable Mention: MBRP 4" Turbo-Back AL Series '98-02 S6100AL


  • Three-year warranty
  • Allows the turbocharger to whistle during acceleration
  • No welding or modifications required
  • Includes all necessary hardware for installation
  • Looks great thanks to the chrome exhaust tip


  • Damage to the exhaust system can cause severe rusting
  • Some users report problems with the included hangers

What Recent Buyers Report

With a nice engine sound and improved performance numbers thanks to better exhaust flow, the MBRP 4” Turbo-Back AL Series is a true winner. And while the aluminized steel may rust in harsher weather, most users report that routine cleaning of the undercarriage should ensure the longevity of this product well beyond the three-year warranty period.

Why It Stands Out to Us

If you’re searching for an affordable exhaust system that allows you to get the most out of your 5.9 Cummins turbo, this is the product you’ve been searching for. And with the bonus of easy installation and a nice growl, this exhaust checks all the boxes.

Bottom Line

When you want to hear the whistle of your turbocharger without breaking the bank, the MBRP 4” Turbo-Back AL-Series is your greatest ally. That said, those who want more peace of mind (due to stainless steel construction) may want to go with the MBRP’s XP Series.

Types of Diesel Exhausts

Diesel exhaust systems aren’t just a one-size-fits-all equation. You have several different options depending on what you’re going for. So add these different exhaust options to your pile of research before you make an aftermarket exhaust purchase for the 5.9 Cummins.

Cat-Back (Pre-DPF Generations)

An aftermarket cat-back exhaust is an exhaust system that attaches to the truck after the catalytic converter. Before the mandate of DPF exhausts (diesel particulate filter), this was a common aftermarket upgrade. While you may not see much uptick in performance, the growl provided by a cat-back exhaust is worth the expenditure.


Following EPA emissions laws in 2007, diesel-powered vehicles had to be equipped with a DPF-back exhaust. These exhaust systems use a filter to trap ash and soot, effectively reducing the number of emissions spewed into the air. If you don’t have one for your 5.9 Cummins, you may need one to pass emissions tests. Besides, these exhaust systems can improve exhaust flow, lessen back pressure, and may also keep your warranty intact, if applicable.


A turbo-back exhaust is a full-length exhaust system that attaches to the vehicle right after the turbocharger. In a 5.9 Cummins, this will allow for maximum exhaust flow, which translates to better horsepower and torque compared to the stock exhaust.


Downpipe-back exhaust systems are another option that can provide some powerful benefits over stock systems. OEM systems may use cheaper metals and have several bends, but a downpipe-back allows for better airflow due to straighter tubing, essentially improving the overall performance of your truck.

Get the Most Out of Your 5.9 Cummins With a Top-Notch Exhaust System

With an aftermarket exhaust system for your 5.9 Cummins truck, you don’t have to worry about restrictive airflow, backpressure, or any of the other pitfalls of a basic exhaust system. Not only will your truck purr ferociously, but it will also have better performance, improved power numbers, and an alluring rear end to boot. Few other aftermarket parts can offer such a plethora of awesome benefits.

People Also Ask

Because exhaust systems come in so many different styles for every type of budget, you may have some additional questions about them. Here are some of the top questions people also ask about the best exhaust for the 5.9 Cummins diesel engine.

What Is A Safe EGT For A 5.9 Cummins?

An EGT, or exhaust gas temperature, is a gauge/sensor that measures the exhaust gas temperature of a vehicle. If it gets too hot, you risk damaging the engine or other engine components. In a 5.9 Cummins engine, 1,200 to 1,500 degrees is the maximum EGT you should shoot for. Any higher, and you could damage the engine. However, the onboard computer typically defuels the engine if you reach this point, acting as a failsafe in this regard.

How Many Miles Is A 5.9 Cummins Good For?

If properly maintained, many owners of 5.9 Cummins trucks state that the engine should last somewhere between 300,000 and 500,000 miles. This far outlasts other vehicle components, so make sure to take a look at the ball joints, U-joints, and transmission, as these are more susceptible to failure than the engine itself.