Go Back   986 Forum - The Community for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical Chat

 
 
LinkBack Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 04-17-2007, 10:34 AM   #11
Registered User
 
Join Date: Oct 2006
Location: MD
Posts: 447
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.
John V is offline   Reply With Quote
 



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 10:56 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page