Background:
I’ve been testing various component combinations of the CC Design turbo-back exhaust to characterize sound levels and frequencies. CC Design recently sent me an alternate rear muffler to test.
Product:
The new component is a suitcase-style muffler that will replace the dual Stainless Bros. mufflers that are currently fitted to the exhaust.
As with the current muffler, the exhaust tips are separate parts to be installed. The latest tips have a subtle slant cut on the exit side, whereas the current tips have a straight cut.
The new muffler section uses 3.5″ piping, the same diameter as the CC Design resonated midpipe.
With the muffler installed, I test-drove to compare sound levels and dominant frequencies with the previous configuration.
Test Results:
The suitcase muffler reduces the cabin sound level from ~1,500 to ~2,500 RPM, with the largest drop at the lower end of the “complaint zone“. The complaint zone is where the majority of time is spent operating, and therefore any annoying sounds in this region are especially unwelcome.
The next chart is a bar graph version of the data shown in the line chart.
In addition to reducing the sound level compared to the dual-muffler configuration, the suitcase muffler more effectively absorbs annoying frequencies.
In the complaint zone, the dominant frequency drops from ~89 Hz to ~61 Hz — moving well below the 100 Hz drone boundary.
Sub-100 Hz content jumps from 59% to 94% of samples, now exceeding the Magnaflow muffler reference (92%).
Conclusions:
The Suitcase muffler shifts cabin sound toward lower frequencies and reduces sound levels in the driving range where drone matters most to the driver.