When you come across terms such as test pipe and downpipe, that’s when you know how complex the exhaust system is. It is normal to confuse between the two.
The test pipe comprises a small section in the exhaust system where the catalytic converter is located. On the other hand, the downpipe is the exhaust part that connects the turbine housing to the exhaust tip.
This is just one of the many differences between a test pipe and a downpipe. Below, we will discuss in detail what they are and everything else you need to know about them.
What is a Test Pipe?
If you know a thing or two about cars, you are familiar with catalytic converters and their role in vehicles. These objects are designed to convert harmful gasses into less toxic emissions from the engine.
As good as catalytic converters are, they create some backpressure, limiting your vehicle’s horsepower.
For car enthusiasts who want to enjoy the full horsepower of their vehicles, a test pipe can be of significant help.
In a turbocharged car, the test pipe, as mentioned earlier, is located where the catalytic converter is. Without the latter, there is no backpressure, and the car enjoys unrestricted engine flow. As a result, you can now access your vehicle’s full power.
Also known as cat delete pipes, test pipes do not feature a catalytic converter. They improve your car’s performance by preventing back pressure in the exhaust system. When you look at a test pipe, it is a tube that acts as a catalytic converter replacement.
If you replace your catalytic converter with a test pipe, there is no conversion of harmful emissions into harmless gasses.
All the toxins coming from your engine manifold flow are released from the exhaust without any restriction. A test pipe isn’t the most environmentally friendly accessory to have in your car.
Despite its ability to improve power and performance, it may release a lot of harmful gasses into the air. Because of these reasons, test pipes are illegal in some parts.
If found with one, you may get fined or penalized. Before replacing your catalytic converter with a test pipe, confirm with the local authorities first.
Besides upgrading engine performance, installing a test pipe allows your vehicle to achieve a deeper sound.
The sound is even more appealing when you connect a test pipe with a resonator. If you have been craving a deep engine sound, then it’s high time that you consider a test pipe.
For car owners who prefer a more aggressive sound, you can opt for a straight pipe. This doesn’t limit the flow of gasses in any manner, and that’s why the sound coming from the mufflers will be deeper.
A test pipe can offer many benefits. And before we look at what a downpipe is, we must mention the following. As much as you have the freedom to fine-tune your car using accessories such as test pipes, you must consider the environment you reside in.
if you live in an estate that has noise policies, then you should be mindful about deepening the sound of your car as well as emissions.
To enjoy maximum car performance, as you fine-tune the exhaust system, don’t forget about the intake system as well.
What is a Downpipe?
The main similarity between a test pipe and a downpipe is that both direct gasses. The difference applies to where the gasses are being directed to and from.
A downpipe in your car exhaust channels exhausts gasses from the turbine housing to the exhaust system. Similar to the test pipe, the downpipe plays a critical part in a vehicle’s exhaust system, more so in a high-performance car.
The role of the turbine housing is to collect exhaust gasses and direct them to the turbo for it to spin. The downpipe directs exhaust gasses from the turbine housing. Due to its role, the downpipe must perform efficiently for the car to run smoothly.
Custom downpipes often feature restrictions that can make your vehicle lose some power. If you have just bought a high-end car, chances are you want to experience its full potential, and the custom downpipe might limit you to some extent.
Aftermarket downpipes often feature a bigger diameter which guarantees more flow and better performance.
Replacing the downpipe with an aftermarket option also boosts turbo efficiency. The bigger diameter pushes the turbo to spin faster, thus generating more power.
If you get a bigger downpipe on a high-performing vehicle, you will notice the difference and significant gains in power.
If you want to enjoy more performance, you can remove the catalytic converter and replace it with a test pipe that will remove any limitations.
How Are They Different?
1) A test pipe replaces the catalytic converter, whereas the downpipe leans more towards improving turbo performance. When you upgrade it, you get a bigger one that increases the flow of gasses, which boosts turbo efficiency.
The test pipe eliminates the catalytic converter in your car. As a result, the gasses in the exhaust aren’t restricted, leading to improved performance and better sound. A downpipe upgrade prevents turbo lag which might limit power.
2) If you are stuck between, which you should replace, we recommend the test pipe. Upgrading it is most likely going to give you more gains. The catalytic converter significantly limits horsepower and performance.
However, there are no restrictions once it’s out of the picture, and you will notice significant gains in power. This is, however, more a matter of preference. With more research and depending on your needs as a car owner, you should determine which option is best for you.
How Are They Similar?
Both;
1) Direct gasses. The test pipe directs gasses to the turbo, and the downpipe directs the gases from the turbo to the exhaust tip. Both play a significant role in directing gasses, and upgrading both will improve car performance.
2) Have some legal issues. Replacing the test pipe or downpipe is not recommended, and you will fail emission tests. Removing the catalytic converter is considered tampering with a car’s engine.
Also, upgrading the downpipe reduces restrictions which raises emission concerns. Before tampering with your exhaust system, you should do some research and find out if it’s okay to do so in your area.
You should also be mindful of your car’s impact on the environment. Because without a catalytic converter, the vehicle cannot convert harmful toxins into harmless gasses.
What’s Better about a Test Pipe Upgrade?
In matters related to improving sound and performance, you should upgrade your car’s test pipe. A test pipe can enhance these aspects of your vehicle since it eliminates the catalytic converter.
The role of the catalytic converter is to break down exhaust gasses and make them less toxic. As this happens, the engine experiences some form of restriction, and your vehicle loses a considerable amount of power.
You don’t have to worry about the catalytic converter restricting power with a test pipe. You will therefore enjoy maximum horsepower and better sound.
Depending on your car’s make, it may realize that the catalytic converter isn’t working, and the check engine light may turn on. This shouldn’t be a cause for concern.
What’s Better about a Downpipe Upgrade?
You enjoy fewer restrictions with a downpipe upgrade as gasses come from the turbine housing to the exhaust tip.
The benefit here is that a bigger diameter ensures faster movement of gasses coming from the turbo. This means that there won’t be any lag.
If you want to enjoy more efficiency in a turbocharged car, you should consider getting an aftermarket downpipe.
The faster gas is being channeled from the turbine housing, the faster the turbo spins, and the more powerful your engine will become. This upgrade is an excellent choice for car owners who want to enjoy a turbocharged engine’s full power.
Who Should Upgrade a Test Pipe and Why?
Some car enthusiasts upgrade both the test pipe and downpipe at once to enjoy all the benefits. Most, however, prefer only to upgrade one. If you are stuck wondering which option should you pick, here are reasons why you should upgrade the test pipe.
Immediately the test pipe replaces the catalytic converter. You will notice a significant improvement in the power and sound of the vehicle.
Unlike the cat, which often restricts the flow of gasses, the test pipe allows free movement of gasses, making the vehicle utilize its full power. As this happens, the sound produced also deepens.
The biggest concern with a test pipe upgrade is with emissions. Without a catalytic converter, there won’t be anything to convert the toxic gasses into something more environmentally friendly.
Who Should Upgrade a Downpipe and Why?
A downpipe upgrade isn’t as popular as that of the test pipe. That, however, doesn’t mean it’s not beneficial. When you upgrade the downpipe, the vehicle notices an increase in turbo efficiency. If you own a turbocharged engine and would like to improve it, this is the best upgrade for you.