@Supermoto I’m in a similar boat. Clamped in Vibrant resonator, but to a AWE Track exhaust, and am experiencing drone in the same RPM range.
From a different thread, a knowledgeable member suggested clamping instead of welding is the root cause of the drone problem.
I feel like I read that somewhere as well, however I dont see how it could make that big of a difference if all the clamps are tight. Either way, at this point I have nothing to lose so I will be welding the majority of the system next week when the stainless wire arrives. I might try moving the vibrant res closer to the downpipe.
Noico 80mil in the hatch area and under rear seats helped a lot. A hi-flo cat does help quiet it down a bit too AFAIK.
I have worked with noico in the past when covering the entire inside frame of a MX5, its good stuff. However from my experience it doesnt tend to help with exhaust drone very much as drone is a resonation of the entire frame due to the exhaust frequency. Its a possibility though.
Pictures supermoto? I do know the second piece that goes in curves and the tail of the first piece curves but idn
The whole system is installed right now for testing, but when I have it out next week to weld I will take pics.
I cut out the 2.5” section so it’s 3”all the way. Removed the first big resonator and had the vibrant welded in. Drone was definitely reduced but it’s still there from about 2,500 to 3,200. I have the catless rev9 downpipe as well which I bet is the big culprit here for the drone. I’m not gonna modify the exhaust anymore as it’s not a daily driver and it’s tolerable at this point. The drone is at its worst under boost, not bad at all when just taking it easy, and under 2,500 it’s very quiet.
I still have to remove the 2.5" section, besides that I have the same setup as you. For me though, the drone comes on strong at 2.5k regardless if im under boost or not, its just
a lot worse under boost. As someone else said, welding the system might make a difference so I will be doing that soon, cause at this point I don't have much to lose. My downpipe is kinda hacked together and I was planning on replacing it in the future, so maybe when that day comes the drone will die down.
Edit: After research, I am heavily considering a 1/4 wave resonator. It would need to be around 20.5 inches and theres room in the front part of the tunnel. Not sure what diameter to make it out of, but welding a 90 degree J bend to the side of the exhaust and extending it to be a total length of 20.5 then capping it should solve the issue of the drone patch at 2.5k rpm.