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Originally Posted by 3SRT4ME
My experience, and I believe that of many others, is that the objectionable drone was a function of the interior tone/resonance change brought about by the C going into MDS or 4 cylinder mode. Given that are SRT8s are always firing on 8, I don't envision the drone issue being nearly as prevalent, if at all present.
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A dramatic harmonic is introduced when the motor shifts MDS modes. We had to incorporatea completely different design to counter this shift. We started with an external x much like the factory part but when the exhaust pressure was reduced the dampning effect of the x was as well reduced. We had to locate the x all the way inside the first muffler (mid-body) and perforate the x to minimize the MDS "buzz."
Now as far as resonance goes, this noise is function of the noise cancelling capacity of the muffler AND system pipe design. Both noise and harmonics due to exhaust pulse contribute to cab resonance (this is the loud booming in the cab) that typically occurs when the engine is under high load and low throttel position. There are many ways to combat this ranging from harmonic dampners to changing exhaust pulse character through modifying turbulance/laminar flow, speed/heat and balance such as that provided by a cross over tube of sorts.
Each application changes how effective a certain approach will be at reducing noise. There is NO one best way. I does infact take time and testing.
Richard
