Interesting Info on Intake Resonators

[xl_cheese]

I was curious why engineers were adding these appendages to the intakes now. They seem to be for more than just noise reduction and actually have a performance goal. Found this bit of information.

https://physics.stackexchange.com/q...a-side-branch-intake-resonator-helmholtz-work

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[Sabre]

I was curious why engineers were adding these appendages to the intakes now. They seem to be for more than just noise reduction and actually have a performance goal. Found this bit of information.

https://physics.stackexchange.com/q...a-side-branch-intake-resonator-helmholtz-work

That was really interesting...my knowledge base just increased again....thanks for posting!

 

[KingKona]

Time and time again;

Unless you're doing LTHers, just leave the factory CAI alone.

 

[joe603]

I think it's a balance between HP and sound coming from the intake. Interesting read for sure.

 

[Cobra Jet]

I was curious why engineers were adding these appendages to the intakes now. They seem to be for more than just noise reduction and actually have a performance goal. Found this bit of information.

https://physics.stackexchange.com/q...a-side-branch-intake-resonator-helmholtz-work

Good deal of info!

Now someone will corner the market to gathering and selling the stock Helmholtz resonators @10x the original cost back to those who removed/trashed that "ugly thing" and plugged the hole.

 

[WD Pro]

that "ugly thing" and plugged the hole.

That made me laugh considering the Ford supplied item looks like a large butt plug hanging under the intake tube ...

WD

 

[Skye]

Attached is a study of the phenomenon. The chamber is akin to the ones used in exhaust systems.

In general, the resonators are being used to cancel noises at certain RPMs. Excepts follow.

Regarding the charts and dB readings, the variations in sound might seem insignificant, but consider...+3 dB doubles waveform power while -3 dB reduces power by half. With sound waves, the inverse square law is also in-play: doubling distance from a sounding object reduces the received power not by 1/2, but by 1/4.

"Pressure variation in the fresh charge of the induction system of internal combustion engines is responsible for: (1) potential ``tuning'' by ensuring the return of the initial rarefaction wave in the form of compression wave before the intake valve closes; and (2) generation of airborne noise which propagates to ambient through the inlet snorkel."

"The narrow-band nature of the sound attenuation of the resonator is clearly demonstrated by the significant overall [Insertion Loss] IL at engine speeds with fundamental firing frequency near the resonance frequency and insignificant reduction at other speeds. With the exception of 1000 rpm, the intake primary runners are found to be nearly insensitive to the presence of the Helmholtz resonator. The impact of the resonator on the volumetric efficiency and therefore torque is hardly noticeable (within less than 2%) at engine speeds with fundamental firing frequency near the resonance frequency."

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