Help with exhaust noise
 

Hey everyone,

I am a new Z owner and I noticed that there is a weird exhaust noise. It mostly happens when the RPMs start to drop, but it does happen more often than that.
I posted a video on YouTube to show you all what I'm talking about.
Any help would be greatly appreciated!

https://youtu.be/MXhM3hA3JH4

Thanks,
Josiah

What exhaust mods do you have as its obviously not stock...this might help.
From what I can hear it sounds like you have un resonated test pipes at least.
I dont hear any tapping, or rattle sounds just the raspiness of a test pipe.

Thank you for your response!
All the exhaust work was done prior to my purchasing it.
It does have test pipes and I believe the exhaust to be a custom job with no muffler.
I like the sound of everything except that high pitch noise when it's coming back down.

Z33Garage is right. It sounds like you have non resonated test pipes, combine that with a "custom exhaust" and you could get unique results like shown in the video. There is a small chance something else is going on, perhaps a leak downstream of the test pipes. Your best bet is to inspect it yourself or take it to a shop. For daily driving I'm personally not a huge fan of test pipes (resonated or not) because of the high pitch tin can sound you often get (Also living in CA makes this a huge chore every two years when smog checks are due). If I were in your position, I would replace the "custom" portion of the exhaust system with a known, tried and true maker like Invidia, Motordyne, Fast Intentions, Bassani, Nismo, etc. That's just me, but there's so many options, I'm sure you could find something that fits your goal.
-Icer

I've checked everything out and there is no leak. Test pipes aren't an issue because I'm in South Carolina so there is no emissions testing.
I guess I'm failing to understand the science behind why test pipes would cause a squeak like sound when it's backing down?

What you're hearing is commonly referred to as "rasp" which is common with test pipes due to the increase/difference in the exiting exhaust gas. Read more here: https://my350z.com/forum/intake-exha...pipe-rasp.html

Ah, okay. Thank you. I did not know that is the sound that is called a "rasp." Haha doesn't sound raspy to me but I certainly don't like it.
I do love the overall tone and volume though :D

Thank you for your response!

You're hearing what I used to have when I had the Stillen Y-pipe with decats/straight pipes.
Check if your Y-pipe has flexi's or not, if it's solid pipe work you're going to get some weird goose hissing noises like that exacerbated by the decats.
You can try a different y-pipe or get different decats with Helmholtz piping (ARK/Motordyne).