Helmholtz resonator by-pass + airbox modification

[krestian]

Hi Guys

On all my previous cars I have always modified the airbox to improve the sound under acceleration. Cutting big holes in the original airbox( in front of the filter) normally gives the deep growly sound that I like.
A modified airbox is louder mainly when the flow through the filter is increased( acceleration), but is not much louder at steady flow( constant speed eg motorway)

On my 2000 Boxster S I have discovered two resonance chambers( helmholtz resonators) on the air intake pipe.

are these resonators there for sound or for flow tuning?
If they are there for inlet flow tuning, then I will not touch them.
If they are there to lower the noise, then the question is if it is overall noise in order to comply with regulations? or are they there to take out distinct annoying resonances?

I found a similar discussion on a US 997 forum.

http://www.6speedonline.com/forums/showthr...0190&page=2

Now, I am thinking of doing the airbox modification + bypassing the resonance chamber on my 2000 Boxster S, but before I do, I want to hear if any of you guys have done this to your boxster and hear about your experience?

Best regards

 

[Richard_Hamilton]

I've seen it written up on the 996 forum (http://www.porscheclubgbforum.com/fb.asp?m=277390) and elsewhere, so it probably works with a 986. It didn't make much difference when I blanked off the chamber on mine, but it seems to have different results depending on what exhaust you have.

 

[krestian]

Thanks Richard

Lots of info now

cheers