The location of a car's air filter is too far from the turbo to make any difference in sound. The factory air box is designed to dampen sound, so unless you have a cool air intake with a tube and cone filter, your intake will sound the same. With turbo cars, the inlet is connected to the turbo, so you will hear more of the groan and the exhaust valve without the box. High-performance air filters, such as those from K&N, are made of foam, coated with oil. Without the air box, the sound of air entering your car will no longer be muted, providing you with a louder and more aggressive sound when you step on the accelerator.
In theory, high-performance air filters should make the engine sound louder because they increase airflow. I was looking for an air induction kit, just because of the noise, but also because of such a slight BHP gain. In the case of my car, a capsule filter made the induction noise 5 times louder and the relief valve was also noticeably louder. It made no difference in terms of sound or performance (the design seems to be free-flowing, but the actual gain is negligible).However, there is another type of air filter that comes in the shape of a cone: they are larger and are much more exposed. Which means that they restrict the amount of air that can enter the engine and, theoretically, this can reduce performance.
I think the main benefit of the K&N filter is that you can clean it, which will save you a little money over time.Dust particles, flies, insects, sand - there are a lot of impurities in the air, and they should not enter the car engine. Although the cold air intake is marketed to increase power, the real beauty of the cold air intake is the unique sound it provides. This way, the air cleaner is widely exposed and you will hear a louder sound from the air flowing into the engine as you accelerate.
