The larger BMW engines have always been noted for the sound they produce. Somewhere between a sense of unleashed power matched by a feeling of opulence and luxury. BMW’s tagline, “Sheer Driving Pleasure,” is never more experienced than listening to one of its vehicles accelerate away at high speed.
There are a few ways to increase the sound of a BMW exhaust:
- Change the muffler on your BMW
- Install a complete aftermarket exhaust system
- Install an exhaust tip on your BMW
- Connect your exhaust system with welded hangers
Before selecting the type of modification, you want to make, carefully consider what you intend to achieve. Some improvements may increase the sound and performance, whereas others will only work on the sound.
Here’s How To Make Your BMW Exhaust Louder
Six- and eight-cylinder BMWs engines are renowned for their smooth signature sounds. The power plants produce a unique sound that hints at the restrained power lurking under the bonnet.
The factory-equipped exhaust compliments the sense of refined muscle waiting to be unleashed.
Some petrolheads want more – much more!
If you are looking to make your BMW exhaust louder, you should first consider your goal. Are you looking to increase the vehicle’s power, or do you only want a more aggressive sound?
This article discusses the options available to increase power AND sound and then sound only.
Increasing You BMWs Power And The Exhaust Sound
By changing the capabilities of the exhaust on your BMW, it is possible to increase the available horsepower. I do want to note, however, that when making exhaust modifications you should keep in mind that horsepower in a vehicle is generated internally from the engine. If you are not making modifications to the engine block (think piston, camshaft, and turbo upgrades), you are typically going to see at best modest performance gains in exchange for a lot of time and money.
It is also important to remember that when your BMW was designed and engineered at the factory, the designers chose the engine and exhaust configuration because it provided the best balance of performance, fuel economy, driveability, and durability.
If you make a significant change, you may lose this balance, and what you increase in power and sound, you may lose in the other three factors.
With this in mind, If you are planning on changing any of the BMW’s components to change the car’s characteristics, it’s a good idea to obtain advice from a BMW professional.
Changing The Exhaust System
Internal combustion engines need enough oxygen to ensure that the spark plugs ignite the fuel.
Four cycles occur within the engine’s piston chamber, which are:
- Intake – the air-fuel mixture is drawn into the chamber.
- Compression – The air-fuel mixture is compressed.
- Explosion – The spark plug ignites the mixture and causes an explosion.
- Exhaust – The gasses are forced out of the exhaust port.
If the size of the exhaust is too small, it may restrict the volume of gasses removed via the exhaust port.
It could cause a build-up of pressure, which may restrict the amount of fuel oxygen that can be input into the cylinder chamber, making the spark plug less efficient, which makes the size of the explosion smaller, and thereby reduces the engine power.
Performance exhausts claim to get around this problem by:
- Reducing the back pressure which prevents the problem just described.
- Creating a particle vacuum to actively “pull” the exhaust gasses out of the cylinders.
Therefore, a performance exhaust can cause the exhaust gases to flow more quickly by reducing the restriction and actively sucking or ‘scavenging’ them out.
Theoretically, as the combustion chamber has more space to inject the fuel/oxygen mix, the engine makes more power.
The Power Gains May Not Be Achieved
The reality is that a modified exhaust will produce minimal additional power on cars that are normally aspirated (non-turbo).
In BMWs equipped with turbochargers, the exhaust gasses drive the turbo. If the exhaust flow is less restricted, the turbos will spin faster, which will cause higher boost pressure and, therefore, better acceleration.
It does not apply to supercharged engines because the crankshaft drives the superchargers.
If you want to increase the engine power, we suggest you research other possibilities thoroughly because a performance exhaust system may not achieve the improvements you were hoping for.
Sometimes, lower-cost options can improve performance more effectively than an exhaust.
Changing The BMW Exhaust To Make It Louder
If you are only looking for an increase in exhaust volume, then several options are open.
Change The Muffler On Your BMW
The existing muffler on the BMW has been specifically designed to generate the sound it does.
Removing this and replacing (or deleting) the muffler with a unit containing fewer baffles will dramatically affect the sound your BMW makes.
Alternatively, there is an option to install a “straight-through” muffler, making the exhaust significantly louder and reducing the backpressure to the manifold.
Once again, discuss the change with specialists to ensure that the most suitable muffler is chosen.
You should also be aware that “technically” a muffler-delete is illegal pretty much anywhere in the United States. I know, this is one of those rules that is obviously frequently ignored, evidenced by the fact that there are lots of people in my hometown driving with straight-piped Hondas. Just be aware that deleting your muffler may cause some issues with passing inspections and technically you can get ticketed.
Install A Complete Aftermarket Exhaust System
In these instances, the whole exhaust system is replaced with a prefabricated unit designed specifically for your model BMW.
Aftermarket exhaust systems may include cutback and performance throughflow systems.
Although suppliers of these systems claim an increase in power, we suggest that your primary aim should be to change the exhaust sound (which will be awesome). You will certainly get an HP increase, but it will be limited to somewhere on the scale of 1-5 HP, this kind of increase is almost completely unnoticeable on a 300-400 HP car.
Install An Exhaust Tip On Your BMW
Because you are only looking for an improvement in your BMW’s sound, an exhaust tip designed to change the exhaust note is a very viable option.
These tips are readily available and can be chosen according to the sound you want.
If you intend to install an exhaust tip, consider the following points.
The Size Of Your Exhaust Tailpipe
Ensure your exhaust tailpipe has sufficient diameter to fit the exhaust tip intake.
The intake side of the exhaust tip should be the same as your BMWs exhaust tailpipe.
The Exhaust Tip Construction
Exhaust tips are generally made from aluminum or stainless steel. Both these materials resist heat and corrosion.
Only purchase an exhaust tip made from these materials.
Make Sure The Exhaust Tip Is Suitable For Your BMW
Some exhaust tip manufacturers supply exhaust tips specifically for BMW vehicles, and these would be the preferred choice for your BMW.
Choose The Sound You Want
For a relatively low cost, exhaust tips are devices that you can select based on your sound requirements. Whether you are looking for a deep base roar, aggressive growl, or even a higher pitch “turbo” type sound, there is an exhaust tip available for you.
Some of the best BMW exhaust tips are made by Active Autowerke. These tips are fully adjustable and are extremely simple to install!
Connect Your Exhaust System With Welded Hangers
BMW installs the exhausts on its vehicles using rubber hanger mounts.
These are to reduce the amount of vibration and rumble generated between the car and the exhaust.
If you replace the rubber exhaust hangers with welded metal units, there will be a noticeable increase in sound in the passenger cabin.
It can work too effectively, and the sound in the cabin may become unpleasant.
Conclusion
BMW designed its products to achieve the most desirable driving experience for its consumers. If you want to change the exhaust systems, despite what you may hear to the contrary, you will probably not achieve the considerable gains in power you may have been hoping for.
If the purpose of the exercise is to make your vehicle roar, then look for the lowest cost method to achieve the sound you are looking for. It is suggested that an exhaust pipe tip will produce the best result.
References
https://www.motorbiscuit.com/do-performance-exhausts-really-increase-horsepower/