Annoying Car Sounds Explained: Exhaust Drone

There are many sounds that your car may make that you can easily ignore—exhaust drone isn’t one of them. It can be a deep bass sound that will rattle everything in your car when it reaches certain RPMs. Loud, disruptive sounds like this bring many customers in to our service department to investigate the problem.

You may have experience the sound our came across the term on automotive blogs, but never understood what it is. So here’s a basic overview of what exhaust drone is, what causes it, and how to prevent it.
 

What Causes Exhaust Drone?

Exhaust drone is caused by a combination of sound waves travelling through the air and vibration that is travelling through your car’s frame, body and components. When the sound frequency between the engine and exhaust align it causes a pressure wave. When this pressure wave occurs, it causes serious vibration in your car and a loud droning noise that drives drivers and passengers inside crazy.

The conditions that cause exhaust drone have to be just right for it to occur. The design of a muffler’s baffles may also play a huge part in muffler drone. When an engine’s RPMs increase, the cylinder’s exhaust valve will produce sound waves that will also increase with the speed. As this sound travels through certain mufflers, it gets enhanced.

Exhaust drone may not be totally avoidable, but that doesn’t mean it can’t be controlled. Factory exhaust systems are designed and tested to reduce issues like this. However, many aftermarket mufflers may have increased drone on certain frequencies. Some are designed with baffles to counteract it or have a frequency that is either too high or too low to be noticeable.

How to Reduce Exhaust Drone?

You may have bought a car with an aftermarket exhaust system or installed one yourself. Now, you need to know how to fix it. Here are some basic steps that our service department may be able to do for your car.

One possible fix is to install thicker-walled tubes that run from the catalytic converter to the tail-pipe. This can help because thicker tube can have a much lower frequency than thinner tubes do. Many times, this means that thicker steel tube may also put on a little more weight, but it may be all you need to solve the problem.

For many cars, another fix is to shorten the exhaust pipe. This works because certain frequencies are generated by the length of the exhaust pipe. If it matches the frequency that is coming from the engine, then it generates the drone. So, shortening the pipe may not allow the frequencies to match up. If you have a dual exhaust system, shortening one of the pipes has also been known to help.

There are also some aftermarket resonators that you can attach to your exhaust system. However, it’s best to have an experienced mechanic perform any work on your exhaust system.

The technicians in our service department are experts in the difference between the performance of factory and aftermarket parts. They will also be able to know how if any changes or additions will affect your vehicle’s warranty.

For unusual noises you experience in your car, visit our expert service department. Our experienced and knowledgeable technicians can find and fix any problems in your car. If you have any service questions, give us a call at (405) 632-3600 or visit our convenient location off I-240.