For those members with HFC's
 

I'm going nuts listening to the vibration sound between 3-4K RPMS. I thought I read a thread recently where someone used exhaust wrap to cover the HFC's. For those of you who want to know if this will really work, I'll let you know if about 1 week. I ordered my exhaust wrap today and I'll probably have it installed next Friday.

Hey, i wrapped my exhaust with heat wrap (Invidia Q300) and i wrapped few 350z test-pipes, that thing works, it'll reduce the heat when you stand next to your car, kill the raspy sound, and you'll hear what your exhaust really sounds like, it helps in reducing the echo/sound travel, it'll greatly deaden the sound, maybe you can read more as i discussed this matter before:

https://g35driver.com/forums/v36-eng...xhaust-20.html

I hope it help, but don't over wrap the HFC, otherwise the heat well never find a way to cool down.

Thanks for the advice. I'll check out your thread.

Well, I had my exhaust wrap installed last night. Definitely sounds a lot better. I still have that terrible "swoosh" sound when the car shifts but the wrap was a big improvement. Money well spent in my opinion.

I'm glad it helped, now just imagine the whole exhaust is wrapped in it, i really don't feel like having a cat-back at all :p, i used 75ft. to wrap my Invidia Q300 exhaust.

I don't know exactly how the piping is configured but the shop told me that they started a few inches in front of the cats and went all the way past a "Y" in the pipes. Before installing the wrap they put it on a lift and tried to figure out where all the noise was coming from and apparently it was in the "Y". I'm assuming this Y is half way between the cats and mufflers.