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Semi Truck Dual Exhaust: 11 Super Facts You Should Know!

Semi Trucks require exhaust to let the air out of the cylinders faster and help the engines. Aside from the excellent appearance, it also provides better functionality for the truck’s engine. 

Semi Truck exhausts also help other drivers from getting fogged out by the smoke emitted by the truck.

Here’s a Short Answer to Why Semi Trucks have Dual Exhaust:

Semi Trucks have dual exhausts to provide more airflow thus expelling exhaust fumes faster. The dual exhaust also results in a quieter engine because there is lesser gas being forced through the smaller areas of the machine. Moreover, dual exhaust improves the overall horsepower of the engine. 

Do all Semi Trucks come Fitted with Dual Exhaust?

Not all semi-trucks come fitted with dual exhaust. However, most modern semi-trucks come with a dual exhaust system for fuel economy and improved horsepower.

In addition, a truck with eight cylinders is typically come equipped with dual exhaust. On the other hand, those with an OEM exhaust system typically use a single exhaust design.

This is because a single exhaust design is affordable, low-maintenance, and provides a good balance of economy and power.

If you wish to upgrade your single exhaust to a dual exhaust system, you can do so with the help of a professional mechanic.

However, there are also single exhaust aftermarket upgrades that will allow you to experience the benefits of having a dual exhaust system.

But according to professionals, the dual exhaust still works better than the single exhaust system because of the extra pipe. Thus, many truckers choose to upgrade from a single exhaust to a dual exhaust system.

Are Semi Truck Dual Exhausts Just for Aesthetics?

While dual exhaust provides a tremendous aesthetic vibe for the semi-truck, it works more than just its looks. 

The dual exhaust helps the engine in more ways than one. For example, it helps the engine emits quieter sound. Plus, it allows fumes to be expelled faster. 

More than that, dual exhausts are not manufactured and installed on your semi-truck just for the looks. It is made to match and serve its purpose of helping your engine for a better experience. 

Does Dual Exhaust Help MPG?

Yes, dual exhaust increases MPG or mile-per-gallon of a semi truck. Many factors affect gas consumption in one drive, and the exhaust system contributes to that. 

Dual exhaust increases your engine’s fuel economy and ensures that it will have enough energy for the semi truck.

Does Dual Exhaust Change the Sound of your Semi Truck?

Semi trucks being too big of a vehicle creates a roaring sound on the road. This is quite normal, but it may be better for it to be quieter for the welfare of its surrounding. 

Good to know that dual exhaust makes semi-trucks engine emit lesser sound. 

The two exhaust pipes allow better airflow for the fumes to get out of the engine faster. Also, lesser gas is forced into the small areas of the machine, promoting a more quiet engine. 

Does Dual Exhaust need Two Catalytic Converters?

Catalytic converters are necessary for vehicles because they remove harmful elements from the automotive exhaust. It includes rhodium and palladium. 

The catalytic converters also convert these toxins to safe components needed by the engine. 

In this case, vehicles with dual exhaust need two catalytic converters to make the engine’s function easier. It may be costly since the converters are stainless steel, but it is worth it. 

Is a Dual Exhaust Better than a Single Exhaust on a Semi Truck?

As mentioned, some trucks have a single exhaust only. At the same time, most of them are on the dual exhaust. 

Dual exhaust is best for a semi-truck to help its engine function and perform better than when in a single exhaust. 

Dual exhaust provides many good things, such as a quieter and cleaner engine and even helping the driver. 

The dual exhaust also promotes better gas mileage and increased horsepower, thus more acceleration and better speed. 

How much Horsepower does Dual Exhaust Add to a Semi Truck?

The installation of dual exhaust in semi-trucks results in to increase in horsepower.

The increase ranges from 15% to 20% from the semi truck’s original horsepower. For example, your vehicle will gain 30 to 40 hp if your truck has 200 hp.

There is an increased horsepower in the dual exhaust system because as the air and fuel mix in the internal combustion engine, an explosion occurs to fire the piston.

After such an explosion, the remaining gasses in the engine come out through the exhaust manifold.

The increased gas that comes out from the engine significantly affects the air intake, increasing horsepower and torque.

What are the Pros and Cons of a Dual Exhaust Semi Truck?

Dual exhaust is an excellent treat for your semi truck. Let us check out its pros first to better view this remarkable modification. 

Increase in MPG

The dual exhaust system in your semi-truck will provide lesser engine backpressure, which means less wasted energy. 

Low fuel consumption happens when the engine is energy efficient. This is great because you can save more on fuel expenses. 

Horsepower Increase

Dual exhaust pipes provide better access for the burned gases out of the engine faster. Two exit pipes are better than one. 

As a result, it increases the engine’s horsepower giving you better performance and fantastic acceleration. 

Cools the Engine

With two exhaust pipes in your engine, hot air created by the engine is expelled faster. Thus, it will not leave the engine heating up, unlike when you only have a single exhaust pipe. 

Overheating can cause problems to your engine in the long run. Combat this with a dual exhaust system. It will be worth the investment. 

Now that we know the pros let us look at the other half of it- the cons.


Since this will be an addition to your vehicle’s specifications, it will cost extra. Not to mention that it is made with quality materials and requires different parts to match your car. 

Prone to Rust

Since the dual exhaust pipes don’t get too warm, they are more prone to moisture due to the condensing from the exhaust. In this sense, it will get rustier than a single exhaust pipe. 

This means you will get to change them more often. A rusty pipe may cause more damage to your engine if left untreated. 

What Stack are Types Popular for a Semi Truck Dual Exhaust?

Look into the types of stacks suited for a semi-truck dual exhaust. Check out which matches your preference. 

Tech Nine

Tech Nine is the newest in style, perfect for those looking for a more aggressive look. They are available in monster stacks or standard tailpipes. 


This stack is named after a hometown in California where a customer created his stack to help smoke get out of the engine faster, 

Eagle Claw

If you want something that will make you stand out on the road, Eagle Claw will suit you. Its modern and unique design is set to make a statement. 


This stack is named after a lunch stop where truckers usually hang out. This design is the customer’s favorite. 

Flat Top

A classic look will never go wrong. Having this on your semi-truck will mean that the old king will never be out of style. 

Short 30

If you are torn between curved exhaust and bull hornpipes, Short 30 is perfect for you. It sits just between the two styles, hitting two birds with one stone. 

Can you make a Single Exhaust into a Dual?

You can make a single exhaust into a dual. In fact, many truckers upgrade their single exhaust system into a dual.

However, you have to be aware of the consequences it may offer. 

Transforming from single exhaust to dual exhaust will cause many modification processes and be costly. It may also cause smog check failure. 

If you have this checked by a smog technician, he will consider this as a tamper. Keeping your original exhaust system is very important to keep the warranty. 

If you are eager to have dual exhaust on your semi-truck, you must check out professional help to avoid problems.

But if you are not risky enough to splurge some money, you can go for aftermarket single exhaust upgrades.

After all, there are a lot of aftermarket single exhausts nowadays that are comparable to dual exhausts.

How much does it Cost to Put Dual Exhaust on a Semi Truck?

The price starts at $500 and may go up to $2,000 depending on the parts you would like to add. Here are some of the features that you may include: 

Exhaust Manifold

The exhaust manifold is in charge of collecting and removing post-combustion fumes. It may cost you around $160 to $330. 

Flange Gasket

This sets the seal between the exhaust manifold and exhaust pipe. It costs $1.50 per piece.

Catalytic Converter

It is from $800 to $1200, and the catalytic converter is responsible for keeping harmful emissions out of the engine. 

Middle or Cross Piping

It holds the resonator.


Allows the engine noise to travel to the muffler.


This costs $75 to $300 depending on the brand of muffler you will choose. It hushes the engine sound and creates backpressure for better performance. 

Other things that may affect the cost are the following:

Labor Cost

Of course, the experience level of your mechanic or technician will differ from one shop to another. LAbor cost per hour cost $50 to $60. Hence, the total cost range can be about $50 to $120. 

Do not settle for less, as this will be a vital part of your semi-truck. Paying for less might end up in more maintenance and repair costs. 

Your Semi Truck’s Make and Model

Of course, brands define the cost of the parts that will be used. 

Exhaust Material

This will determine the exhaust’s durability. 

Type of Exhaust System

It usually costs $300 to $1200 for a complete exhaust system. Your two options will be after-market products or original equipment manufacturers. The difference is the former is cheaper because they are generic copies.