I recently put on a Fabspeed maxflo exhaust with the sport headers. I absolutely love the sound of the exhaust. The only problem was that around 2200RPM, it would resonate pretty loudly. Typically it was the worst when decelerating through that rpm. I could hear it when accelerating through 2000rpm also but it wasn't as loud, probably because I didn't spend a lot of time in that range on acceleration.
I read just about every thread in the forum concerning exhaust drone and resonance but wasn't satisfied with doing nothing, or taking the new exhaust off and putting the stock exhaust back on; not after hearing what the Fabspeed put out.
I got under the car and looked around a bit and noticed that the pipe that bends into the muffler was butted up against the heat shield. After tapping around on the heat shield in that area, I figured that on deceleration, the exhaust would then vibrate causing the heat shield to vibrate as well. This is where all the noise was coming from. The pipes were touching the heat shield on both sides of the car.
I took a trip to Home Depot and bought a Flame Protector, found in the plumbing aisle. See picture. It cost about $15. It feels like heavy duty felt and it is good up to about 2500 degrees F. It also acts a great sound dampener. So, I cut a section of the flame protector to fit between the exhaust pipe and the heat shield. I didn't have much room in between, otherwise I would have doubled up the material on the left side. I had more room on the right side so I did double up there.
I took the car for a drive and voila. I can still feel a little resonance but I can't hear it anymore.
