Originally Posted by badwithcomputer
I have this muffler with the Roush CIA and it drones like a mother on the highway at 1800rpm.
My buddy says it's the CIA that's making the exhaust louder, I can't really wrap my head around that but maybe he is right!
It's the muffler. This platform tends to drone in the 1800-2200 rpm range, especially under load (pulling a hill, a trailer, etc).
Some folks experience this - other don't. One fix is to put a bullet in front of the muffler - acts as a resonator. The larger MangledFlows don't do it as much if at all.
CAI/WAI's can do this as well - another seemingly random symptom.
Try-before-you-buy if you can. Some shops are amenable but most are not.