All done and drone GONE. So happy. Our target frequency was 100hz which I was getting at 2000 rpms. This calculates to a 33.72” chamber. After driving around and examining areas with drone and also to account for variables such as exhaust temperature, design etc my shop designed an adjustable helmholtz resonator that can adjust from 30” to 42”. The main tube size is 2.5” with a 2 3/8” tube slipped inside (12” long) and clamped to stay in place.
We spent a lot of time changing the length then driving around and seeing the impact. It seems to kill drone within a roughly 500 rpm range and we ended up at 32” which kills 1900 to 2400 rpms.
Did a great job tucking them up and hiding them behind the rear bumper too so it doesn’t impact the good looks of the setup.
I hear nothing but road noise now at normal cruising speeds around town and highway but still sounds so mean under acceleration. Now this is done I’ll work on getting sound clips.