turn350

I have a 3inch catback exhaust, aftermarket y pipe, stock cats, i have this noise that almost sounds like a burrower bee buzzing noise every time i accelerate/ am going a constant speed. I have looked everywhere on here and posted videos on facebook groups and no one can figure it out, i work at a nissan dealership and the mechanics cant even figure it out. I replaced both gaskets were the cats join the y pipe and it is still making the noise, Do any of you have a similar issue? Like i said it sounds like a buzzing noise almost like a powered razor (id post a video but it wont let me)

travlee

iTrader: (8)

is it a resonated cat back? have you checked the head shields to see if they are vibrating

turn350

It is resonated, and i took all the heat sheilds off when i installed the y pipe so there arent any heat sheilds on the car so thats why im getting frustrated

travlee

iTrader: (8)

it is possible that the material in the resonator could be busted loose

turn350

Should i just have a muffler/exhaust shop check it out then?

travlee

iTrader: (8)

take resonated part down.... hit it with palm of hand, if it is loose you will hear it

dboyzalter

iTrader: (3)

Could stick your stock system back on and see if the noise goes away if you still have it. It's odd if a mechanic looked it over and couldn't figure it out unless they did a half assed 5 minute looks good to me bro kinda diagnostic. How are the heat shields on your exhaust manifolds and catalytic converters?

DaveJackson

iTrader: (5)

Bump. I'm having the same issue except it's mainly when I'm DEcelerating and it's pretty unique to about 1800-2500 rpm. I do have resonated test pipes - Megan. I didn't think there was anything in the resonators. I thought they were just an empty cavity. Are you sure about ^this?
I crawled under it for a long time today and took the heat shield off of the y-pipe. No change. Listening very carefully under it, the noise is almost certainly coming from the flex pipe on the driver's side. It sound like there's a freaking marble rattling in there! But, you can't hear anything from tapping/banging on it without the car running.
If this resonator "material" is true, I bet a chunk came off and worked is way downstream to get stuck in the flex pipe.
Sound reasonable? Any other suggestions?

dboyzalter

iTrader: (3)

If they didn't have any resonator material in them I think they would leave the word resonated out of the name. I know when i had a test pipe on my old car it wasnt called resonated because it was a straight piece of 3 inch exexhaust pipe.

But it sounds like you might have pinpointed your problem so you should probably remove that side of you y pipe and see if a piece of megan racing quality comes out of it.