Best Exhausts For LB7 Duramax – 2021 Guide

| Last Updated: December 25, 2021

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Are you a Duramax enthusiast? If you can tell from only the sound of an engine, if it's Duramax or not, then consider yourself a true enthusiast. 

For those looking for exhausts to upgrade your LB7 Duramax, we have got you covered with a detailed review of some of the best options you should look into. 

Considering the range of options available on the market, the decision about which exhaust to buy can be overwhelming. So, here we are to help you out!

Comparison Chart of the Best Exhausts For LB7 Duramax

  • Mandrel bent tubing for superior flow
  • Provides better throttle response
  • Improves overall performance
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  • Aluminized construction with bent design
  • Great sound and improved performance
  • Easy installation with all provided fittings
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  • Best for the Money
  • Made from heavy-duty aluminized steel
  • Provides better performance and sound
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  • Best 5 Straight Pipe Exhaust Lb7 Duramax
  • Improves fuel economy
  • Easy bolt-on installation
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  • Mirror polished exhaust tip included
  • Provides a mellow exhaust sound
  • Designed to improve over-all performance
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When is it Time to Replace My LB7 Duramax Exhaust?

Taking care of a Duramax demands a lot of attention. You need to be aware of the technical stuff. Not focusing on the engine panel may cause a lot of damages. When you are aware of your LB7 Duramax technicalities, you also know about the replacements and parts.

When the LB7 engine starts, white and hazy smoke is emitted, and the engine oil levels increase. If this is happening with your engine, then there is a need to replace the exhaust. The dripping at the nozzle causes the white smoke, and it is quite noticeable.

What Size and Type of Exhaust Should I Opt For?

Let's face it; it is not easy to keep an LB7. But, it is much more challenging to find the parts for a Duramax. The majority of the exhaust systems are restrictive, and they are heavy as well. Also, the entire system of an LB7 Duramax is not as simple as a regular car.

Firstly, you should identify the type of exhaust system—header-back, cat-back, and axle-back. The type will be identified by measuring the diameter of the other parts in your car. The type of exhausts also depends upon the noise and pitches. If you want a sound system, you can go for a cat-back, if you want a deeper tone; header-back and axle-back would work. 

Now when it comes to the size, you will get two options. You can go for a four-inch or a five-inch exhaust. The former will give a higher pitch, whereas the latter will give a deep pitch. A four-inch cat-back exhaust would work perfectly if you are looking for loud pitches. On the other hand, a five-inch header-back or axle-back might be your interest as it will give a deep pitch. 

You might need professional help in identifying the type of exhaust. Once you are done with this, you need to make a combination of header, piper, converter, and tailpipes. You need to do a bit of calculation about the size, the horsepower, and the number of exhaust pipes.

Review of the Best Exhausts For LB7 Duramax

Improving the performance and horsepower of LB7 Duramax requires a lot of understanding. Not everyone can understand the speed, functionality, and measurements of an engine. If you are an avid user of LB7 or want to purchase an exhaust for it, go through the reviews below.

Best Overall:
Diamond Eye 4" Turbo Back Exhaust


  • Decreases fuel consumption
  • Provides a deep sound to your vehicle
  • No need to spray any lubricant while installing
  • Offers a powerful performance with no loud noise
  • Installation process does not require any professional


  • Comes as a single unit
  • Does not provide any additional horsepower

What Recent Buyers Report

A large number of highly satisfactory reviews make this product the best on our list. The majority of the buyer reports tell us that the unit is easy to install and does not require any professional help. Also, it does not make any additional noise and decreases overall fuel consumption, allowing them to cut costs longer.

Why it Stands Out to Us

Admirably, this product has a lot to offer. It has a sturdy stainless steel body with a coating that resists corrosion. Moreover, this product decreases fuel consumption, which makes it an economical turbo-back exhaust.

Additionally, it provides high-performance that, too, with no barking noise. By installing this exhaust in your LB7 Duramax, your vehicle will get a deep tone noise. This Diamond exhaust stands out to us because it can be paired with some other products, which can help in efficiently increasing the performance. The best part about it is, you don't need to hire any professional to install or assemble it. So, there will be no installation costs, either.

Bottom Line

If you are looking for a back-turbo exhaust with high-performance and no loud noise, this is the ideal pick for you. Also, the unit increases fuel economy so you will be able to enjoy it for a long time.

Runner up:
FLO~PRO 4" Downpipe Back with Muffler


  • Features a mandrel-bent design
  • Does not affect the sound of the engine
  • Comes with a high-performance muffler
  • Decreases the overall weight profile of Duramax
  • No need to attach an additional catalytic converter


  • Attaching this downpipe might result in loose pressure

What Recent Buyers Report

Most of the recent buyers seem to be satisfied with this product. They believe this downpipe has what it takes to increase the horsepower of a Duramax without much of a hassle. The majority of the users reported improvement in their vehicle after installing this unit.

Why it Stands Out to Us

Well, there are many things that we admire about this unit. Firstly, this back downpipe comes with a muffler. The unit is aluminized, allowing resistance to rust, and there are no installation issues reported even by first-time buyers and users. Secondly, this downpipe increases the overall performance, creating an authentic engine sound that is not unpleasant for the car owner.

Besides, there is no need to attach any catalytic converter with it as it works without any support. Even if you have a V-band clamp on the bottom of the downpipe—there will be no fixing issues. Also, it eliminates CAT and DPF, with a three-bolt flange.

Bottom Line

Despite being a bit lose on the pressure, this Flo-Pro 4 inch Downpipe back is a pretty good option. You don't have to worry about the extra installations; this single unit with the muffler will do all the work on its own.

Best for the Money:
Magnaflow 18982


  • Comes as a complete 5-inch kit
  • Made out of heavy-duty mandrel bent
  • Equipped with the dyno-proven power
  • Encourages economic fuel consumption
  • Installation is easy with the help of clamps that come with it


  • Might emit more gases than other units
  • Resale of the Duramax might be hindered

What Recent Buyers Report

A high percentage of positive reviews backing this product suggest that it performs like any other high-end unit but by remaining budget-friendly. The clamp style is beneficial for easy installation.

The product comes with all the detailed instructions. Moreover, it saves on fuel consumption and does not require any complementary attachment. The noise is not irritating, and it does not produce any additional horning sound.

Why it Stands Out to Us

When you talk about a budget-friendly product, this Magnaflow model is the best at it. At such a price, you will be getting a remarkably efficient product. Taking care and understanding the technicalities of an LB7 Duramax is not easy. With Magnaflow, it is easy to fit the pipe without any help from a professional.

Also, it enhances performance, as reported by its buyers, without increasing or changing the engine's sound that might annoy the driver. It is made out of a heavy-duty mandrel bent, and it does not disturb the other parts. Besides, this unit is also compatible with the majority of the vehicles, as it is a five-inch long pipe.

Bottom Line

If you want to purchase an aluminized exhaust pipe at the right price, this is the ideal pick for you. With all the smart features, you will enjoy the efficiency and effectiveness of this unit without spending a huge load of money.

Best 5" Straight Pipe Exhaust LB7 Duramax: 
Diamond Eye 5" Aluminized Exhaust


  • Features a silent resonator
  • Fuel economy will be benefited
  • Guaranteed to improve throttle response
  • Known for increasing horsepower and torque
  • Comes with helpful instructions for installation


  • Requires a catalytic converter
  • Noise exposure in the cabin is quite high

What Recent Buyers Report

Put in simple words; this straight pipe exhaust is the most convenient way to increase the horsepower and torque in an LB7 Duramax. There is no need to think about the perfect size and diameters, as it comes with a direct fitting design that has resulted in even first time buyers to love this product. Moreover, the quiet resonator is the smartest feature of this unit.

Why it Stands Out to Us

What strikes us about this product is its versatile features. It increases performance by increasing the overall horsepower. Additionally, there is no need to get the calculation of the diameter; it is a sufficiently long straight pipe exhaust that fits comfortably.

The increased throttle response is another commendable feature that is enjoyed by all users. The higher horsepower also decreases fuel consumption, leading to cost savings in the long term.

Moreover, this model by Diamond is aesthetically pleasing since it is a straight pipe with no attachments. The location of the mounting clamps is accurate, and just by following the instructions manual, you can fix it.

Bottom Line

For those looking for a straight pipe exhaust that can increase the horsepower and decrease fuel consumption, you might be interested in this unit. Also, this straight piper does not need to be measured in diameters as it is a direct fit.

Editor's Pick:
MBRP 4" Exhaust Single Outlet


  • Backed by a three-year warranty
  • Helps boost torque and horsepower
  • Appearance and the sound both are pleasant
  • Comes with mirror-polished stainless steel tips
  • No need to use special hardware tools for installation


  • Might hinder the backpressure
  • Has little to no effect on fuel economy

What Recent Buyers Report

There are a lot of buyers that report the superb quality and functionality of this product. The majority praised the stainless steel tips, as they look aesthetically pleasing. Additionally, the noise performance is up to the mark and does not suppress or encourage any extra sound.

Why it Stands Out to Us

The high-quality, stainless steel tips meant to resist corrosion and rust are what stand out the most in this product. This exhaust increases the horsepower up to 120 and does not produce any additional noise.

It also comes with a three-year warranty that can further enhance its reliability and make it a good investment.

If you're worried about the installation, know that it requires no special hardware!

Moreover, there is no need to attach any extra component to support this single outlet. The easy-to-fit and easy-to-carry style of this exhaust make it excellent for LB7. The overall build makes it look a bit fancy, but the features are indeed robust.

Bottom Line

To conclude, we find this product as one of the most commendable singlet pipes. If you are looking for a direct fit, then this might be your pick. Additionally, if you are someone who won't be bothered by the cabin noise, this unit will suit you well.

Pros and Cons of Upgrading Your LB7 Duramax Exhaust

There are a lot of options when it comes to tuning or upgrading your LB7 Duramax Exhaust. However, before upgrading, you must be aware of all the factors, benefits, and disadvantages.

Let's talk about some pros and cons of upgrading your LB7 Duramax Exhaust.


When it comes to raising the performance bar of LB7 Duramax, there are a lot of advantages.

Increased Performance 

The main reason why most Duramax enthusiasts buy an exhaust system is improved performance. There is a potential increase in a vehicle's overall performance when an exhaust pipe is installed.


When a Duramax climbs up the hill, the driver feels a back pressure exerted on the engine. When an exhaust system is fitted, the gases flow freely hence reducing the backpressure.


The majority of the exhaust system increases the horsepower and torque, allowing the engine to work freely. Moreover, in some of the cases when the horsepower is increased, the fuel economy also improves.


With all the benefits, there are disadvantages too.

Unnecessary Emissions

A lot of the exhaust systems are not compatible with catalytic converters. When an exhaust system is installed, it does not hold back the emissions. The harmful gases are emitted when the fuel burns to generate energy.

What Do I Need to Know Before Buying a New Exhaust?

You must know certain things before buying a new exhaust, especially if you are buying it for the first time or if you are a beginner Duramax enthusiast. Before you set your mind on purchasing an exhaust kit, you need to see whether you know everything about it.


You cannot just simply go to the market and buy an exhaust kit. You have to know which is the right, most compatible size. Without knowing the diameter of your Duramax's fittings, you cannot buy an exhaust kit.


When you add a part to your vehicle, it can disturb the other original parts. You need to check the products to see if they are soundproof. Not all exhausts produce additional sounds, but you need to check this factor before purchasing the unit.

Type of Exhaust

Before you make a purchase, you need to make sure that you are well-aware of the purpose of the product. There are different types of exhausts—header, piper, converter, back-pipe, tailpipe, etc. Ensure that the kind of exhaust you are buying will fit in your LB7 Duramax and meet your needs.


If you want to install an exhaust kit in your LB7 Duramax, you will have to decide with extreme care and thought. There are many technicalities to exhaust systems, including sound, performance, mileage, horsepower, corrosion, etc. The best way is to make sure that you are well aware of your purchase's purpose and have your preferences cleared out.

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.