Do you have a 718 GT4/Spyder/GTS 4.0L and are you more sensitive to the amount of cabin drone/resonance in your car, whether it be stock or accentuated by various aftermarket exhaust configurations? You’re not alone, and if you’ve been following our Exhaust Development Thread you might know that Porsche has piped extra sound into your cabin through the firewall right behind your seats via a vibrating diaphragm called a Sound Symposer (and this is not the only car they do this in). Over the past month or so a few Rennlist members and customers of ours have been pursuing DIY modifications of deleting that sound symposer, and have reported significant reduction in drone/resonance in the cabin with different exhaust setups including various manufacturers. Spurred by this feedback, we documented the process for the Porsche community to reference, and hear the difference for ourselves.
KIT INCLUDES TWO CAPS TO COVER ENGINE SIDE OF SYMPOSER AND FIREWALL PORT
If you have any questions about this process or the results – please contact us. Modify your vehicle at your own risk.
To start, here is a Porsche diagram to show the full scope and functionality of the sound symposer:
With all engine covers removed, here’s the symposer as it sits from the factory:
Symposer section removed and remaining tubing capped:
Interior side of the cabin port:
The resulting delete is effective in reducing in cabin drone even on a stock 718. Here is a guide we made to show the process (on a Boxster GTS but the steps will be very similar for other models).