Discovery on STi JDM axleback and perhaps others
 

Some times ago I fitted the STi JDM axleback, instructions said to replace nuts, gasket, and hangers, but I didn't do it as my car was new.
I was happy with the sound, except an annoying resonance at 3000 rpm.
I asked here, and I was said it was drone, nothing to do, characteristic of the exhaust; it was not drone to me, but a resonance inside the cabin.
Recently I discovered a japanese article: I was right, and I made a great mistake.
I didn't check the part numbers of the additional parts, as I took for granted that they were the stock ones; but the hangers weren't, they were a different part number!
The article said that the cabin resonance frequency of the 86/BRZ is 125 Hz, and the STi steel exhaust (the titanium one don't) needs that specific hangers to avoid the noise. AND THIS WORKS!
If you have resonance, and you want to try risking just few bucks, you have to replace just the 2 rear hangers (the ones toward rear bumper) with 44066AJ010 part number. The front ones has to remain stock.

Thank you, I might have to give this a try. I experience pretty much the same thing around the same RPM with my Blitz Nur-Spec R, because it's pretty tame and drone-free at any other speed.

Amazing how even the exhaust hangers have some sound engineering behind it.

before and after video clips would be awesome. my system is loud, but im not sure if i should call it drone or resonance, or just loud.

I tried taking videos, but it's completely useless, like all videos on exhaust noise, you have to hear it in person to understand dB, pitch etc..

Yes. I am using these 2 STI rear hangers.

What exhaust do you have? Thanks!

The same like gpvecchi. The STi JDM axleback.

Where did you find the Axle-back?

Imported from Japan

Thank you sir! Another small mod to keep my mind busy.

a good explanation of why OEMs spend so much time and money on R&D.

Confirmed working with the replace of all 4 hangers on HKS Spec-L.

I ordered mine on the 15th and they're still not here...

I ordered the remaining 3 (one for midpipe too, it's the same as the others), I'll update with the results.