Why Do Superchargers Whine? Typical Causes and Solutions

“Why do superchargers whine loudly?” is a question many drivers ask after hearing the high-pitched sound a number of times. Superchargers produce a whine due to how they operate.

The sound can be as thrilling as it can be confusing. This article explains why superchargers whine and how to fix it.

Why Do Superchargers Whine Loudly?

Superchargers whine loudly because of the type of supercharger and the number of blades. Other common reasons for this issue are the size of the supercharger, the air pressure, the nature of the belt drive, and the low supercharger oil level.

• A Noisy Type of Supercharger

A noisy type of supercharger is the main reason superchargers produce a whining noise. There are two primary types of superchargers: centrifugal and Roots. Centrifugal superchargers are commonly found in high-performance vehicles, while Roots superchargers are typically used in muscle cars.

The air movement and speed of a supercharger determine the sound it produces. Centrifugal superchargers operate by compressing air drawn in through the engine’s air filter and transferred to the engine. This process is quieter because the air moves through the impeller and diffuser at a slower rate.

However, Roots superchargers use two meshing lobes to compress the air. The lobes rotate at high speeds, causing the air to be drawn in and compressed, which results in a whining noise.

• A Larger Supercharger Size

The size of the supercharger can also affect the level of the whining noise. The larger the size of the supercharger, the more air it can compress and the higher the speed of its internal components, typically resulting in a louder whining noise.

Bigger engines usually draw more air and fuel to their cylinders. By introducing pressurized air into the engine, a supercharger can significantly boost the engine’s power capabilities. In general, larger superchargers can generate more power due to their ability to force greater volumes of air into the engine.

• The Nature of the Belt Drive

The nature of the belt drive you use determines the extent of the whiny sounds from your supercharger. The belt drive’s tension impacts the pitch and volume of the supercharger’s whine, with a loose belt producing a lower pitch and volume and a tight belt producing a higher pitch and volume.

Another aspect of the belt drive that affects the supercharger sound is the size of the belt used. For instance, a wider belt will produce a deeper, more aggressive sound in the supercharger. On the other hand, a narrower belt will produce a higher-pitched sound, making the supercharger whine louder than normal.

The material of the belt drive can also impact the whining sound of the supercharger. For instance, a supercharger using a rubber belt produces a softer and smoother whiny sound. On the other hand, a Kevlar or carbon fiber belt produces a sharper and more aggressive sound in the supercharger.

• Higher Number of Blades

The number of blades on a supercharger also affects the whining sound it produces. Generally, superchargers with a higher number of blades produce a higher-pitched whine, while those with fewer blades produce a lower-pitched whine. If your supercharger whines too loudly, you are most likely using one with many blades.

The sound difference is because the number of blades determines the frequency at which the supercharger spins. A higher number of blades means that the supercharger spins at a higher frequency, producing a higher-pitched sound. Fewer blades imply that the supercharger spins at a lower frequency.

• Increased Pressure and Airflow

The airflow and pressure your supercharger produces can significantly impact its whining sounds. This is because the whiny sound directly relates to the supercharger’s ability to compress the available airflow and pressure. Hence, the increased or restricted air pressure makes a big difference in the car sound.

If the airflow is restricted, the supercharger will be unable to compress the air efficiently, resulting in a weaker whining sound. On the other hand, if the pressure is increased, the supercharger will be able to compress more air into the engine, resulting in a more pronounced whining sound.

• Low Supercharger Oil Level

Another reason why your supercharger may make whiny noises is because it is low on oil. Superchargers require lubrication to function correctly. If the oil level is low, there may not be enough lubrication for the bearings and other moving parts of the supercharger. Insufficient lubrication causes them to wear out faster than they should.

As the bearings wear out, they can create a whining noise, which is often a big problem. If the oil level is not checked and maintained regularly, these moving parts can wear out completely, causing the supercharger to fail.

How To Reduce Supercharger Whine Noise

To reduce supercharger whine noise, adjust the belt tension and install sound deadening or soundproofing materials. In addition to these, other ways to decrease the noise are by reducing the supercharger speed, using a smaller pulley or a different oil, and using a different supercharger.

• Adjust the Belt Tension

Adjusting the belt tension is one of the fastest and easiest ways to reduce supercharger whining sounds. To do so, first, locate the tensioner pulley and loosen the pulley bolt. Adjust the tension using a pry bar or a wrench until the belt is tight but still has some allowance.

After adjusting the belt, tighten the pulley bolt, then test the supercharger by starting the engine and listening for the level of the whining sounds. Over-tightening the belt can damage the supercharger and other components, so it is essential that you perform the tasks carefully.

• Reduce Supercharger Speed

Reducing the speed of a supercharger can help to decrease the whining noise. The whining noise is caused by vibrations from the high-speed rotation of the supercharger’s internal components. When you reduce the speed of the rotation, you automatically reduce the activities of the supercharger and, consequently, the whining noise.

To reduce the speed, you can either install a smaller pulley or a larger crankshaft pulley. You can also change the supercharger drive ratio or replace the supercharger with a model that has a lower operating speed. However, you should note that modifying the speed could easily affect the supercharger’s performance.

• Switch to Another Supercharger

If other methods fail to reduce the supercharger noise, you should consider switching to a different type of supercharger to minimize the sound. One option to explore is a centrifugal supercharger, which is designed to produce less noise than other types of superchargers. They also work efficiently.

Centrifugal superchargers operate by compressing air through a spinning impeller, which is driven by belt tension. Unlike other superchargers that produce high-pitched whining noises, centrifugal superchargers are known for their quieter operation. They are also more efficient at higher RPMs, making them popular for high-performance vehicles.

• Install a Sound-Deadening Material

To reduce the supercharger’s whine noise, you can install a sound-deadening material. Begin by choosing a suitable material, preferably one that is designed specifically to reduce engine noise. Clean the surface thoroughly before cutting the material to the appropriate size and shape. Most sound-deadening materials come with self-adhesive backing.

Peel off the adhesive layers and stick the material to the surface. Make sure to press the material firmly and evenly to avoid any air pockets. Repeat the process for all areas where you want to reduce supercharger noise. Test the noise level, then add more material if necessary.

You should note that sound-deadening materials cannot eliminate all engine noise. But they can significantly reduce the noise level. Some whining noise may still be present after installing the soundproofing material, but the sound will no longer be as loud as before the installation.

• Install a Smaller Pulley

To install a pulley that reduces supercharger whine noise, you must first find a smaller diameter pulley that can replace the original one on the supercharger. The new pulley must be smaller in diameter than the original one. Once you have the new pulley, remove the old one from the supercharger.

You will need to remove the belt and the pulley bolts before removing the old pulley. This will help you to access and remove the supercharger pulley easily. After removing the old pulley, install the new one. Make sure that the pulley is correctly aligned with the supercharger shaft.

After installing the new pulley, your next step is to tighten the bolts correctly. Once you have done that, you should reinstall the belt properly. When you start the engine, listen for any unusual noises or vibrations. If everything is working correctly, you should notice a reduction in supercharger whine noise.

• Install a Bypass Valve

Installing a bypass valve is another effective way to reduce supercharger noise. The first step to achieving this is by removing the engine components to access your supercharger. Next, find a bypass valve that is compatible with your vehicle and the supercharger.

Remove the vacuum line and the original bypass valve. You can install the new valve immediately after you remove the old one. However, you will need to connect a vacuum line to the bypass valve for it to operate.

Once you are done, you can test the bypass valve to see if it has successfully masked the noise from the supercharger. If the noise was not concealed to your satisfaction, you might need to try other methods to reduce the supercharger noise.

• Use a Different Supercharger Oil

Using a different type of supercharger oil can be an effective way to reduce supercharger noises. This is because the nature of the oil also affects the sound. Thicker oils have a higher viscosity and can help absorb sound waves, reducing the noise produced.

When changing to a different type of supercharger oil, ensure that it is compatible with your supercharger. Using an incompatible oil can eventually damage your supercharger. You should also note that changing the supercharger oil may not completely eliminate the noise, but the right oil could drastically reduce the whines.

FAQ

– Can Superchargers Stress the Engine?

Yes, superchargers can stress the engine. This stress happens because it forces more air into the combustion chamber, which requires more fuel to be burned. This increases the engine’s power output but also generates more heat and pressure inside the engine.

Conclusion

Now that you know why the supercharger makes whiny noises in your engine when driving, you no longer have to worry about the sounds.

Here is a quick summary of what you have learned in this article:

• The type of supercharger you use is the most common reason your supercharger makes high-pitched, whiny noises.
• The size of your supercharger also influences the noise it makes, as bigger superchargers make more noise than smaller ones.
• The nature of the belt drive, and the higher number of blades also influence the increased whines from your supercharger.
• There are different ways to reduce supercharger noise, including adjusting the belt tension, using sound-deadening materials, and changing the supercharger to a smaller one.

You now know the different factors that cause your supercharger to make high-pitched whiny sounds and how to reduce the sounds if you do not want them.