i noticed your small exhaust looked like the short side looked like it was capped off. is that the resonator like whats on intake boxes on stock stuff?

 

I’m not trying to derail this thread I promise lol


but yes that is a j tube resonator, puts the problem frequency 180* out of phase canceling it. It’s perty simple but if done correctly it is absolutely crazy what it does

( you find the frequency of the problem, then easily find the wavelength of this frequency……… you then build a resonator tube that is 1/4 the full wave length……. Sends the sound wave down a 1/4 of its length and back 1/4 of its length…….. traveling 1/2 its wavelength…… putting it 180 out canceling, very similar to how active noise canceling works)

here is before, showing the problem frequency to tune the resonator for





and here is after, trust me you wouldn’t believe unless you witness lol

 

Coming from the NVH lab at JD I love that setup and use of the resonator.