Quote:
Originally Posted by niky
Also hopefully reduces irritating buzzing and drones, as well.
By silencer I mean a resonator like this:
Some smaller cars around these parts only use a resonator, as the cats already remove most of the sound and you're not getting a lot of noise out of a sub-liter breathing through a paper straw, anyway. |
This style of soundreducer, aka glasspack, are a really great way of reducing noise while maintaining exhaust flow.
The maximum velocity of gas occurs at the center of the pipe while the sound waves propagate and "ride" on the inside wall of the pipe. The perforated ID allows the sound waves to pass through into the sound absorbing material while the gas flow is relatively unaffected.
Also related to noise reduction is pressure. As the pressure increases the sound is reduced. Don't believe me? Idle your car and put something over the exhaust pipe to cover the majority, as the pressure increases the noise is reduced until it becomes a puffing sound.