Resonated Test Pipes sound bad with stock exhaust
 

So this past weekend I installed a set of Beluga Resonated Test Pipes on my Z. I had purchased Berk HFCs off a member on here, however USPS lost my package and after 4 weeks of trying to deal with them I finally gave up and decided to just buy these even though I knew they were a cheaper brand. My friends told me with the exception of ART pipes, most resonated test pipes will sound the same.

My plan was to keep the test pipes paired with the stock exhaust with the exception of the Top-Speed Y-Pipe I had bought for my Z a long time ago but never installed. Installation went well, after spraying PB Blaster on the demon bolts 3 days straight before the install they came off without much hassle.

However, after the install my car is way too loud for my taste and sounds horrible. Under 3k it doesn't sound that bad with light throttle, but any half to full throttle acceleration makes a blaring sound after 3k rpm like a Civic taking off. I thought installing the resonated pipes would give it a deeper sound with less rasp. There is hiss when decelerating from about 2.7k to 2k rpm but after reading on this forum I found out this was common for our motors.

Any ideas on what I should do to tone the sound down? Is the y-pipe causing this? Will installing a resonated catback help or should I just take off test pipes and just money on another set of high flow cats? I also thought of just going down to my local exhaust shop and see if they could add another resonator somewhere to help quiet the exhaust down.

Any advice is appreciated, thank you.

Resonators don't reduce volume.

Like you, I wanted the benefit of a freer-flowing exhaust, without the noise. Originally I wanted to have welded-in performance cats, but found that it couldn't be done. I went with the Motordyne ART pipes, and included some observations in this thread: http://www.the370z.com/intake-exhaus...t-2-5-3-a.html

Now that there are some miles on the exhaust, as the installer suggested, the insides of the new pipes have lined with enough soot to deaden the sound even further. The Garageline X and Mid-pipe combo does add some low-end grumble through the floor, but it's really not that bad.

In my opinion, if you want a quiet-running car, keep the stock muffler (perhaps upgrade to a Nismo), and go with the setup I've done.

So if resonators don't reduce volume would getting a small muffler welded in solve the problem?

Also, is a Nismo exhaust quieter than the stock base Z exhaust? And do you think the new Y-pipe could be a contributing factor to the increased exhaust sound?

Resonators don't reduce volume, per se, but are designed to limit the possibility of drone. A Nismo exhaust is more free-flowing than that on a base model, primarily because of the H-pipe and HKS muffler. This results in a deeper, and perhaps a slightly "louder" tone. If you remove the cats and replace with test pipes, your best bet is a pair of the ART pipes.

Again, if you're looking for more hp/tq, yet maintain a civilized exhaust, follow the advice above. My car just put down 312hp/269tq with the setup described above, yet you can carry on a quiet conversation in the cabin.