I'm wondering if anyone is familiar with the different sized magnapacks enough to weigh in on this. How does going with a larger case diameter change the sound vs going with a longer case? I know going from a 14 to a 18 long muffler is night and day, but how much of a difference is there between a 4" dia magnapack and a 5" or 6"? I imagine the larger diameter would be more effective at low engine speeds and be pretty loud at high rpm because of the exhaust gasses are moving too quickly for the short case to be effective.
So basically by my logic the larger diameter magnapack (6") would provide a noticeably deeper, mellower and quieter idle than the 4" but would not provide as much of a difference in volume at WOT. Am I thinking correctly or should I just not think about mufflers after 1am? I'm thinking about doing a new 3" y back to a si/so and I want it civil at idle but to be mean when I start to lean on it and scream at WOT. Would the 6" dia x 14" long fit the bill?

 

I would think that a 6" diameter casing would give it a lower tone. 4" rounds have a some what higher pitched sound, IMO.

 

^ agreed. The more packing involved I would think would help filter out high frequency sound and give you an all together deeper tone, but also quieter. WOT would also be quieter.

 

Sparko you are spot on with it. The idle of a 4" round wont be all too house awakening though, maybe on a cold start. These modular V8s with stock cats dont idle too obnoxiously, especially with straight through mufflers.

Not too much quieter, just less rasp toned.