Best 5.9L Cummins Exhausts of 2021

| Last Updated: December 24, 2021

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Did you know that your exhaust system is an integral part of your engine? It’s true – exhaust systems are what ensures your engine does not get clogged up with smog and debris, so a well functioning exhaust system can actually make your truck more powerful and more fuel efficient. Read on to learn more about these critical system products.

Comparison of the Best 5.9L Cummins Exhausts

IMAGEPRODUCT
  • Will fit all cab and bed lengths
  • Mandrel bent tubing will provide maximum flow
  • Assembly instructions are simple and easy to follow
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  • Will work for all different bed lengths
  • Will increase both truck’s horsepower and torque
  • Designed to perform in the most extreme environments
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  • Durable, will last for years and years
  • Included hangers and clamps are sturdy
  • Can be installed in under twenty minutes
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  • Will fit all cab and bed configurations
  • Has a two piece tailpipe and bolt on hangers
  • Strikes a good balance between loud and quiet
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Benefits of Investing in a Quality Exhaust

It can be tempting to go with a cheap exhaust option, but here are the reasons why it is more worth your time to invest in a quality model:

Maximum Efficiency

The whole point of an exhaust system is to improve your vehicle’s overall functionality, which exhaust systems do by getting exhaust waste out of your engine and out into the world without letting it gum up your engine’s gears. You are going to want a system that is the top of the line when it comes to efficiency, and for that you will need quality.

Appearance

Appearance should always be a secondary consideration to functionality, but it is true that the more high quality an exhaust system is, the cooler it tends to look. And it never hurts to be the guy with the shiniest tailpipe on the road, right?

Versatility

The best exhaust systems are designed to fit all trucks with a certain engine, no matter what the cab configuration or bed length may be. The last thing you want is to order an exhaust system, wait for it to arrive, and discover it will not even work for your car. Save yourself some trouble and get a quality system with some versatility.

How to Choose an Exhaust for a 5.9L Cummins

Here are some qualities to keep an eye out for when you are selecting an exhaust system for your truck’s engine:

Longevity

Imagine the frustration of installing an exhaust system and then having it break right away, or even a few months down the road. The thing about exhausts is that they are dealing with a pretty intense, hot part of your vehicle’s engine, so you need to make sure your system is made of high quality material that is built to last.

Ease of Installation

Let’s face it, putting something new on your truck can be incredibly intimidating, especially an exhaust system which will definitely involve you physically getting under your car instead of just poking around under the hood. Make sure you make this process as simple as possible by investing in a system with straightforward installation.

Noise

Everyone has a different level of desired noise they would like their truck to produce. And there is nothing more disappointing if you are looking for a system that will make the loudest revs on the road and instead you get something whisper quiet – or vice versa, if you want something streamlined and quiet that then gives you a headache every time you drive it. Make sure you choose a system with the right level of noise for your needs.

Review of the Best Exhausts for 5.9L Cummins

Now that you know more about what makes a good exhaust, let’s look at some actual exhausts:

1. Diamond Eye 5” Aluminized Turbo Back Single Outlet Exhaust  

PROS

  • Will fit all cab and bed lengths
  • Will increase your truck’s fuel economy
  • Diamond Eye provides good customer service
  • Will increase horsepower and torque, as well as throttle response

PROS

  • Parts ship separately, so you may have to wait a bit for it all to arrive

The Diamond Eye 5” Aluminized Turbo Back Single Outlet Exhaust is an excellent exhaust system with all the perks of the Diamond Eye brand as described above with the Diamond Eye 4” Stainless Steel Turbo Back Single Outlet Exhaust. This exhaust system is simple to put together, with straightforward instructions that are easy to follow.

It ships with all of the clamps and hangers required for assembly, so you will not need to purchase any additional components. Its mandrel bent tubing will provide maximum exhaust flow, which ensures that all other aspects of your truck’s engine will run efficiently and your truck’s full power and fuel capability will finally be maximized. Really, there is not much more you could wish for with the Diamond Eye 5” Aluminized Turbo Back Single Outlet Exhaust.

Bottom Line

The Diamond Eye 5” Aluminized Turbo Back Single Outlet Exhaust is an excellent exhaust system that is easy to install and will work wonders for your truck. You may have to wait a while for all of the different parts to arrive, though.    

2. AFE Power ATLAS 4” Turbo Back Exhaust Kit (Aluminized Steel)  

PROS

  • Durable
  • Versatile
  • Easy to use
  • Increases horsepower and torque
  • AFE provides great customer service

PROS

  • Fit can be tricky, may need to be cut to fit exactly

The AFE Power ATLAS 4” Turbo Back Exhaust Kit (Aluminized Steel) is a fancy little exhaust system that will take your truck to the next level. It is customizable to all different bed lengths, thanks to a two piece tailpipe design that allows for adjustability at the tailpipe section (and will make installation as straightforward as it could possibly be).

In fact, users report that the entire installation process will take less than an hour and a half in total. This exhaust system is designed to perform at a high level even when in the most extreme environments.

It includes OE style band clamps to produce a leak free seal to ensure that the maximum amount of exhaust is released from the vehicle and will not gum up your vehicle’s engine. Its mandrel bent 4” aluminized steel tubing will also ensure maximum flow. You will be pleasantly surprised how efficient your vehicle will be once it has a high functioning exhaust system!

Bottom Line

The AFE Power ATLAS 4” Turbo Back Exhaust Kit (Aluminized Steel) is a great exhaust system that will elevate your truck’s performance. It may need to be cut in order to fit your truck exactly, though.  

3. Flo Pro Exhaust Systems

PROS

  • Durable
  • Increases miles per gallon
  • Increases horsepower and torque
  • Well made of high quality material
  • Fits all cab and bed configurations

PROS

  • Instructions can be a bit confusing
  • Does not provide as loud of a revving sound as other models

The Flo Pro Exhaust Systems is an excellent little exhaust system that will help your truck achieve its maximum power and efficiency. It is straightforward and simple to set up – users report that with two people working on the project, installation can be entirely complete in under twenty minutes in total.

It comes with all tools required for installation, including hangers and clamps that are super sturdy and will give you peace of mind that your system is firmly installed and will not come loose, even under extreme conditions. When ordering this system, you can customize multiple aspects of it to ensure you are getting the best option for what your truck specifically needs.

You can choose the system size, finish, muffler, and exhaust type to fully individualize your unique product.  Flo Pro Exhaust Systems prioritizes the customer and their needs over everything else.

Bottom Line

The Flo Pro Exhaust Systems is a great exhaust system that you can fully customize to your own unique needs. It may not be as loud as some other models on this list, though.

4. MBRP Performance Series Exhaust Systems

PROS

  • Made of 100% aluminized steel
  • Well made of high quality material
  • Has a two piece tailpipe and bolt on hangers
  • Can customize size, finish, exhaust type, and exhaust tip

PROS

  • Fitment can be a little tricky
  • Exhaust system can infringe upon truck’s ground clearance

The MBRP Performance Series Exhaust Systems are awesome exhaust systems that you will thoroughly enjoy using on your truck. They will fit all cab and bed configurations, so you do not have to worry about it not matching up with any model from 1994 – 2002.

The exhaust system also strikes a good balance between loud and quiet when it comes to noise level, so you will be able to rev your truck without worrying about deafening yourself. This system comes with a two piece tailpipe and bolt on hangers, so it makes the installation process smooth.

It will increase the horsepower and torque on your vehicle, as well as improve its fuel efficiency, which may come as a surprise to many people. An exhaust system will improve the overall effectiveness of your truck’s engine, which will allow you to reap numerous benefits.

Bottom Line

The MBRP Performance Series Exhaust Systems are fantastic systems that will boost the overall effectiveness of your truck for years to come. The only issue is, it may lower your truck’s ground clearance by a bit.

5. Diamond Eye 4” Stainless Steel Turbo Back Single Outlet Exhaust  

PROS

  • Easy to use
  • Not overly loud
  • Well made of high quality material
  • Easy to install, comes with a bolt on kit
  • Comes with the option to order a cool exhaust tip as well

PROS

  • Pipe may need to be cut to fit better

The Diamond Eye 4” Stainless Steel Turbo Back Single Outlet Exhaust is an awesome exhaust option that really checks all the boxes for truck owners. This exhaust system will enhance your truck’s performance in pretty much every way possible. You will have better throttle response, which also translates to better horsepower and torque.

Though it may seem counterintuitive, this exhaust system is also capable of improving your truck’s fuel economy. Its bent tubing system will allow for maximum flow of exhaust, which will make for a smoother, more efficient engine system all around.

And you will not have to worry about something breaking with Diamond Eye’s awesome warranty system: a one year limited warranty for aluminized kits and a six year limited warranty on stainless steel kits.

Bottom Line

The Diamond Eye 4” Stainless Steel Turbo Back Single Outlet Exhaust is a dope exhaust system that will enhance basically everything you could ever want enhanced on your vehicle. Be aware that you may want to cut the pipe so it fits your vehicle better, though.

6. Silverline Single Outlet 4” (TURBO BACK) Exhaust system

PROS

  • Easy to use
  • Easy to install
  • Increases miles per gallon
  • Tip has bolt on design, so can be adjusted to the desired length
  • Tip has multiple layers and will not suffer from heat discoloration

PROS

  • Tip’s finish could be nicer

The Silverline Single Outlet 4” (TURBO BACK) Exhaust system is a fantastic exhaust system with a number of awesome features to make life with your truck more fun. It comes with a performance muffler, some stainless steel mandrel bent tubing, and a double wall tip.

The mandrel bent tubing will improve your engine’s air flow, which will then increase its available horsepower. The system’s louvers will provide sound deadening for inside the cab, so you will not have to worry about your truck damaging your hearing with its awesome new exhaust system.

It also comes with an awesome warranty: the stainless steel system has a lifetime limited warranty, while the aluminized system has a two year limited warranty. You really are not going to find better than that on today’s market!

Bottom Line

The Silverline Single Outlet 4” (TURBO BACK) Exhaust system is a great exhaust system that will make driving your truck a thousand times better. Some users report the exhaust tip finish was a bit dull, though.  

Conclusion

Exhaust systems can take a tired old engine and make it clean and high functioning again. Make sure you invest in a system that will meet all of your specific needs, including when it comes to the noise you want your truck to produce. You will not be able to go wrong with a model from this list! Did you know that your exhaust system is an integral part of your engine?

It’s true – exhaust systems are what ensures your engine does not get clogged up with smog and debris, so a well functioning exhaust system can actually make your truck more powerful and more fuel efficient. Read on to learn more about these critical system products.

Sean comes from the forums actually and drives an OBS Ford. He writes fantastic DIYs and knows his way around a camera, too. We keep him caffeinated and away from DPF filters to avoid another rant about recent emissions restrictions.