Thread: Stembro Exhaust
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Old 07-23-2007, 03:05 AM   #18
boxsterz
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Quote:
Originally Posted by John V
You're not going to cancel the resonance (the "drone") by inserting more silencers. The straight-through glasspack-style silencers don't do anything for low frequency tones, and the resonance is caused by the low-frequency cylinder firing rate (CFR). I calculated it out to be about 110Hz.

The stock muffler uses helmholtz resonators with absorptive material plus long path length to attenuate the CFR. Any straight-through exhaust is going to resonate between 2-3k on the Boxster, period.

I do believe there are ways which you can eliminate the resonance using quarter-wave resonators and additional tailpipe length, plus reactive mufflers, but I don't have regular access to a welder nor do I have the desire to throw a bunch of money at the problem. Maybe someday.


I'd like to hear your ideas on it, and maybe I'll build it. I have all the tools necessary. You help me design it and I'll build 2; one for me and one for you What do you say? Or do you think there really isn't much power to be gained, and not worth the effort? BTW, I plan on forced induction later on...



I installed Che's exhaust and it sounds racy for sure (PM me if anyone wants to buy it before I put it up on Ebay and I'll give you the details). Just not my taste. I thought I would try it, but it's too loud for me. I like stealth. All I wanted was some more HP.
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