Home-built exhaust with silent/loud capabilities

goldNSX

goldNSX

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15 May 2004
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Anyone seen an exhaust like this: http://www.dk-content.de/tuning/pdf-archiv//Soundprobleme.pdf or http://www.exclusivo.de/pi-1064011619.htm?categoryId=0 or http://www.kreissieg-usa.com/index.php
All supercars are on there but no NSX. I'll soon come up with some drawings (I'm no engineer :)) with suggestions to discuss.
Goal: I'd like to have an exhaust with a silent/loud modus which can be selected from the cabin. Silent should be gf/granny-friendly, sth between CT and OEM, loud should be a little bit above CT.
 
Here we go. I know the picture quality is very bad, I'm gonna improve it. Please remind I'm no engineer so they're only suggestions. I know how a Helmholz-resonator works infact but I have no idea of what 'frequency' will be the input.

Explanations: there are 2 or 3 chambers. There will be Pierburg 'switchs' P1 and P2 which work as a throttle. Green is the silent way, red the loud one. For being silent the throttle has to be closed. Personally I think 3camber1 is the best. For the silent mode the exhaust air will be collected in chamber 2 with a lot of damping material. It then flows via by-pass to cambers 1 and 3 with lesser damping material, then goes out. For the loud mode the air mainly uses camber 1 or 3 directly, camber 2 only works as a Helmholz resonator. So for being loud it only uses 1 camber instead of two.
The walls which divide the cambers don't have to do three equal cambers, maybe chamber 2 could be bigger for more damping material but other frequency as well.

Does anybody has some thoughts about them?
 
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