When it comes to turbocharged cars, the exhaust system plays a critical role in maximizing engine performance. Two popular types of exhaust systems are the bellmouth and the divorced design. Both designs have their pros and cons, and choosing the right one for your car depends on several factors, including the size of the turbocharger, the engine displacement, and the intended use of the car. In this blog post, we will explore the differences between bellmouth and divorced exhaust designs, and discuss the advantages and disadvantages of each. Whether you’re a seasoned car enthusiast or just getting started with turbocharged cars, read on to learn more about these two exhaust system designs and how they can impact your car’s performance.
Bellmouth Vs Divorced
There’s no denying that bellmouth and divorced downpipes share many similarities. It is the sole reason people are unsure of which pipe to choose.
Despite how similar they may seem, in reality, they differ quite a bit.
The primary differences between bellmouth and divorced downpipes reside in their design, noise level, and torque and horsepower output. Moreover, they differ considerably in weight.
I would like to begin the article with a brief discussion of both pipes. Following that, I will discuss the major differences between them.
Let’s get started!
What is a Divorced Downpipe?
Simply put, a divorced downpipe is the one that splits the exhaust and wastegate piping. It is linked to further downstream pipes.
The pipe is also referred to as a divorced wastegate. According to manufacturers, these exhaust pipes reduce turbulence and enhance airflow through the exhaust system.
What is a Bellmouth Downpipe?
The bellmouth refers to a type of downpipe with an entirely open design. However, not all bellmouths are the same.
There is a variety of this pipe known as split bellmouth. It is identical to regular bellmouths, with the exception of a divider separating the wastegate.
Bellmouth Vs Divorced Downpipe
| Key Factor | Divorced Downpipe | Bellmouth Downpipe |
|---|---|---|
| Torque | With two gas exits, torque is improved significantly | Increases torque by a minimal amount |
| Construction | Comes with a design having two separate tubes | Has a single hole, although the split bellmouth possesses two |
| Noise Level | Provides a louder level of noise | Produces a more pleasant sound |
| Horsepower | Generates a small amount of horsepower | Has a high horsepower output |
| Weight | Heavyweight | Lightweight |
Divorced Wastegate Vs. Bellmouth Downpipe: Key Differences
Here comes the most thrilling part. Let’s compare these pipes based on their five main differences.
Torque: Divorced Downpipe
In case you are unaware, torque plays a crucial role in determining how fast your ride goes. It correlates directly with acceleration.
In terms of torque, divorced downpipes certainly are the way to go. Those unsatisfied with their vehicles’ torque usually opt for the divorced downpipe.
Why, might you ask? I will elaborate on it in the next section.
Torque: Bellmouth Downpipe
If you expect to gain a lot of torque from bellmouth downpipes, I regret to inform you that you will be disappointed. Though there is a small increase in torque, it is nowhere near a divorced downpipe’s torque.
Having said that, the bellmouth downpipe should provide enough low-end torque for your car. Please keep in mind that you may need to tune it a bit to achieve that.
Design: Divorced Downpipe
The design of an exhaust pipe matters a lot. Depending on the design, tubes, and holes, the exhaust gas passes differently, affecting the engine’s horsepower.
These two pipes have perhaps the most profound difference in their design. A divorced pipe has two paths for exhaust gas to travel. It is, therefore, apparent that this pipe will have a far better flow.
Remember when I said divorced downpipes produce more torque? Thanks to more efficient exhaust gas flow, they succeed in creating more torque.
Design: Divorced Downpipe
Unlike the divorced downpipe, the gas can only pass through one path in a bellmouth downpipe. As a result, there is very little torque produced, as stated earlier.
An important point to note is that there is a type of bellmouth referred to as split bellmouth. It resembles a divorced downpipe since it has two holes.
Sound: Divorced Downpipe
There are a lot of people who spend hours and hours trying to make their cars sound better. What’s the point of strugglings so much when you could simply install a divorced downpipe?
The pipe has a reputation for being loud: sometimes, a tad too loud.
Hence, I would like to warn you that your car may sound louder than you initially expected with this pipe.
Sound: Bellmouth Downpipe
What I appreciate about the bellmouth’s sound is how balanced it is. There is a rumbling noise that emanates from the divorced pipe. Fortunately, this irritating rumbling occurs less frequently in bellmouths.
Furthermore, bellmouth will undoubtedly appeal to you if you prefer a raspier sound.
Weight: Divorced Downpipe
When it comes to making your car go as fast as possible, weight reduction is of utmost importance.
Unfortunately, divorced downpipes tend to be heavy. In some cases, they won’t add any weight, nor will they reduce any.
Weight: Bellmouth Downpipe
A bellmouth downpipe is one of the lightest exhaust pipes on the market today. According to one user, switching from stock to bellmouth caused his car to weigh 11 pounds less.
If you are acquainted with the weight of a car, you will realize that’s a huge weight reduction.
Horsepower: Divorced Downpipe
Sure, the divorced downpipe has one of the unique exhaust pipe designs. However, regardless of how good it is in increasing torque, the pipe falls short when it comes to horsepower gains.
You will get a slight boost, but it won’t be as potent as a bellmouth downpipe.
Horsepower: Bellmouth Downpipe
Although the bellmouth downpipe directs the gas flow differently, it is highly effective at increasing your vehicle’s horsepower. These pipes usually don’t feature fancy designs like the one in a divorced pipe.
However, the design bellmouth boasts has been well implemented, which is why it generates more horsepower.
Bellmouth or Divorced Wastegate, Which is Better?
It is definitely a good idea to use divorced pipes since the unique design improves torque noticeably.
Nonetheless, I still believe the bellmouth pipe is superior as it increases horsepower and makes the car sound more pleasant while being lightweight at the same time.
Also Read: Gesi Downpipe Vs. Catted
Why Divorced Downpipes Create More Torque?
If you pay close attention to the design of the divorced downpipe, you will see two different tubes/holes. It means two separate routes are available for the gas to pass through.
Moreover, due to the two holes, the exit path has a much faster velocity than a regular or bellmouth pipe.
By combining fast velocity with superior gas flow, divorced downpipes produce more torque.
Also Read: Downpipe Vs Header (In-Depth Comparison)
To Sum Up
The article clearly shows that bellmouths and divorced downpipes differ in many ways. If you desire louder sound and higher torque, divorced pipes are sure to serve you well.
However, those who are seeking horsepower improvements, lightweight, and a quieter sound should consider the bellmouth downpipe.
Did you know that you could pass inspections even with a straight pipe? Here’s how.
