Turbo Flutter: What Causes That Noise?

Are you interested in optimising your engine but unsure where to start or worried that you might do something wrong? Turbochargers are a great way to increase the power and performance of an engine, but they can also make a strange or alluring noise sometimes (depending on who you ask). This noise is called turbo flutter, and several things can cause it. In this post, we'll explain what turbo flutter is, how to get turbo flutter, and how you can fix it if it’s not something you want. 

What exactly is turbo flutter?

Turbo flutter is the noise that occurs after you let go of the accelerator once you hit peak boost. It's caused by the airflow passing over the turbine blades in the turbocharger, which can be pretty loud. 

But is turbo flutter bad? It's usually not harmful to the engine, but the noise can disturb some. This noise happens due to a few things, namely the state of the blow-off valve. Turbo flutter can become commonplace with a modified blow-off valve (or without one altogether). It occurs when the intake air from the turbocharger doesn’t have a place to go since the blow-off valve normally handles this. Without somewhere to go, the air goes back into the turbocharger, creating what is known as turbo flutter.

What is a blow-off or bypass valve? 

A blow-off or bypass valve is a pressure relief system component of turbochargers. Its function is to release compressor surge (pressurised air that tries to escape the turbocharger) and keep it from damaging the turbine blades. 

Pressurised air tries to escape back through the compressor when the throttle valve is closed quickly (such as when lifting off the gas pedal). If this reverse flow of air continued, it would cause the turbocharger's blades to spin too quickly and fail. The blow-off valve opens rapidly to relieve this pressure and protect the turbocharger.

How to make a turbo flutter

Put simply, the easiest way to get any form of turbo flutter in a turbocharged engine is to remove the blow-off valve from your car. Doing this will ensure that the air intake has no smooth way to escape, creating that satisfying noise that we car enthusiasts know and love.

However, if you’re looking for the best turbo flutter that can also benefit your engine, a modified blow-off valve is the perfect option. 

Using a modified aftermarket blow-off valve 

Though you may be tempted to buy just any aftermarket blow-off valve to achieve the best turbo flutter, you need to be aware of fake turbo flutter through subpar products. By purchasing a genuine aftermarket blow-off valve from a reputable provider like Car Mods Australia, you ensure that your turbo flutter is satisfying to the ears and completely harmless to your engine. You can even create some lag to prevent turbo-system damage. 

So, if you’re planning to enhance your car’s engine with mods to increase boost through a bigger super or turbocharger, you can use a blow-off valve to achieve it. By pumping a significant amount of air into your car’s intercooler, the engine will have a buildup of pressure that will throttle the body upon high acceleration. The valve will then increase the pressure even further when you rapidly slow the throttle or brake, creating a compressor surge that is forced back into the turbocharger. At this stage, the best blow-off valves separate themselves from the rest. 

The release of the built-up pressure will create a sound that is specifically dictated by the type of valve you purchase — creating a louder, more aggressive and ultimately more pleasing turbo flutter sound. 

Disadvantages of turbo flutter

For car enthusiasts, creating turbo flutter is highly sought after. Whether you’re looking for a standard loud flutter or a characteristic noise to stand out from the rest, you can achieve it with a modified blow-off valve. 

So, does turbo flutter damage your engine? The short answer is no. However, it can affect performance, such as creating some engine lag, which can negatively affect throttle response, though this will not harm your engine. 

How to get rid of turbo flutter

If you're not a fan of turbo flutter and want your engine to run smoothly in both performance and noise, keep your standard blow-off valve or purchase one that is specifically designed to eliminate noise.

Another thing you can do is to make sure that the airflow into the turbocharger is smooth. This can be done by using a larger diameter intake pipe or by making sure that there are no obstructions in the path of the air — you can also use a different turbine blade design. 

Some designs are less susceptible to turbo flutter than others. Finally, you can tune the engine so that it runs slightly leaner. This will reduce the amount of airflow through the turbocharger and therefore reduce the amount of flutter.

Car Mods Australia — your auto parts expert

So, if you’re looking for an easy way to achieve the best turbo flutter for your tastes, you need to go to a reputable provider. At Car Mods Australia, you’ll find a wide range of Aeroflow turbochargers , blow-off valves, and associated accessories made by the most reliable brands to get exactly what you need. To discuss all the necessary parts and processes involved, get in touch with us and speak to a qualified professional today.