Most car enthusiasts love the sound of a well tuned exhaust and there is nothing more grating to these people than exhaust drone. But what is exhaust drone?
We take a look at this phenomenon and what causes it. We’ll also look at how you can fix it and where you will never hear exhaust drone?
What Is Exhaust Drone?
Exhaust drone is a tone and a vibration that is created by a vehicle’s engine and exhaust at a specific rpm. The tone has an unnatural resonance that is unlike anything you will hear from a stock vehicle exhaust which is more of an organic rumble.
There is no mistaking the sound of exhaust drone, it has the same annoying quality as someone singing off key.
Although some people may not even notice it, for those who love the sound of a well tuned exhaust it’s a noise that cannot be ignored,
So how does exhaust drone happen, and what causes it?
What Causes Exhaust Drone?
Not every instance of exhaust drone will be exactly the same, but there is a general cause of exhaust drone. When the engine’s sound matches the exhaust note a pressure wave is created.
This pressure wave causes vibration throughout the vehicle and this is what creates the exhaust drone. It is not just the exhaust system that is affected. All the internal components of the car even down to your spare tire can add to the droning.
As the exhaust drone occurs at a specific rpm it will be different for every vehicle and exhaust system.
Why Stock Vehicles Don’t Have Exhaust Drone
You won’t find a stock vehicle with exhaust drone. This is because a stock vehicle has not been modified in any way and has been designed to reduce any unwanted or unnecessary exhaust noise.
Engineers spend a lot of time making sure that the vehicles they design are in perfect tune with their exhaust systems (see also ‘What Is A Downpipe?‘).
Exhaust drone only occurs when an exhaust system has been modified in some way. It is through installing aftermarket systems that the problem of exhaust drone will rear its head. It is more likely to occur in a loud, low-frequency exhaust system.
How To Eliminate Exhaust Drone
There are a number of steps that you can take to eliminate exhaust drone.
Mufflers
To get rid of exhaust drone the best place to start is with the muffler (see also ‘What Is A Muffler Delete?‘). They have the most effect on the tone and sound of your exhaust, so it makes sense to begin there.
The number of chambers and the size of the muffler will have a significant impact on the note of your exhaust. This can reduce drone but if you like the loud rumble of your exhaust this effort to eliminate drone will also reduce the sound that you enjoy.
However, there are good quality aftermarket mufflers that will take out the drone but leave the tone that you want.
Modifications
As we have discussed, the cause of exhaust drone is the frequency of its note. Modifying the exhaust will change that frequency and help to get rid of drone.
You can lengthen the exhaust pipe or install a J pipe. These two options will definitely make a difference to how your exhaust sounds.
It is also possible to change the diameter of the pipe or the tips. However this can have an effect on the performance of your car. While trying to eliminate exhaust drone you need to avoid creating other problems with your vehicle.
Exhaust Tips
The purpose of resonated exhaust tips is to slightly alter the note of your exhaust. As part of the problem comes from the tailpipes, changing the tips can work to adjust or dampen the frequency.
Although they don’t produce a huge change it can be enough of a tweak to the acoustics to make the difference and get rid of the exhaust drone.
This is also a more affordable option for those who don’t want to pay out for an entire new exhaust system.
Adding different sized exhaust tips also changes the length of your exhaust pipe. This in itself will change the frequency of the exhaust, but you would have to try lots of different lengths in order to find the right one.
Sound Dampeners
One solution is to add insulation to the interior of your vehicle. This could include engine compartment insulation, sound blocking mats in the car’s interior or even heavy-duty carpet floor mats.
Although this won’t change the frequency of either the exhaust or the engine it will reduce the associated vibration. This should make the exhaust drone less noticeable.
This insulation should have a sound deadening effect and reduce the decibel level inside the car. Dynamat is one such product that you can use for your vehicle’s interior or constrained layer dampening tiles.
Even small changes like securely keeping your spare tire in its allocated place can help.
Replace The Entire Exhaust System
Of course if all your efforts have failed then all you can do is take the whole exhaust system out of your vehicle and replace it with a new one. This is of course the most expensive and drastic solution but at least you will know that the problem will be removed.
Not only will the right exhaust system get rid of the awful exhaust drone but will potentially add performance gains to your vehicle.
There is also the added benefit of having a pleasing, growling exhaust rather than an annoying buzzing drone.
You can also now purchase specific no-drone systems which will eliminate the problem.
Final Thoughts
If you are experiencing exhaust drone due to incompatible frequencies from your engine and exhaust system it can be very frustrating. However, as we have discovered there are solutions to this issue, although each case will be slightly different.
We hope you have enjoyed our guide to what is exhaust drone and that we have been able to help you find a solution.