If you came from stock cats you won't notice a huge low end TQ improvement.. but you will notice the top end improvement. If you come from test pipes, it will be the opposite: you'll notice a huge low end TQ improvement but not any top end improvement.

The only way to have an exhaust with absolutely no rasp or hiss, from every Z I've ever seen personally, is to use stock cats. It's as simple as that. Sadly, there are trade-offs when it comes to modding.. that's just how it is. For all the power you're gaining you have to give up a little something. The hissing on these things is EXTREMELY minimal compared to test pipes.

This is probably a loose ceramic coating bead that got into your ART Pipe when they were making it. Tony already mentioned this earlier in the thread. Did you not read it? ...

I would try to figure out exactly where the noise is coming from first, then go from there. If it's something inside the ART Pipe, I'm pretty sure Tony will take care of you. GL.

Tony said the new production shouldn't have this issue. Though I've already contacted him and he's ready to provide a replacement immediately if I say so. First I want to eliminate the possibility of it being anything else before I waste his time and before I have him send me a replacement I may not need.

Did you listen to the video? It sounds way too metallic to be a loose particle, if you ask me. It also goes away at above the 3K mark.

It shouldn't but if there are any of the ceramic beads, we will use a polishing method... that doesn't involve ceramic beads.

In any event that would be covered under warranty.

Here is a much better video of the sound. Notice as the idle drops, the sound goes away at the very end.

Video - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting

This thread is great! I can't wait till i can order mine

sounds like something is stuck inside the pipes. -- maybe the gaskets?

obviously your dead bolt came out- yours is less than a year old... i wish mine was that easy but it wasn't :shakes head:

Thats exactly what mine sounds like ....

sounds like something's rattling inside the pipes. but how come the rattle goes away by the end of the video?

That's what I don't understand, either. Damn, NeverBoneStock's response has me pretty concerned now. If the ART Pipes failed, I may have to put the OEM crap back on and waste another $120 for that job. And again another $120 to reinstall them - I refuse to drive the car and have it sound like this.

That'd be pretty unfair to pay all that money assuming the failure is the ART Pipes. I'm hoping for the best on Tuesday, but expecting the worst in all honesty.

You don't need to put your stock cats back on I'll send you a proper part. Just let me know which side its on.

Ok cool. I've replied to the PM. If it turns out to be something loose, I will send the replacement back. Let me know when it ships out, Tony.

Thanks again.

i get a hisssss on deceleration on my nismo with CNT res test pipes. just throwing that in there.

Well Arnold, you really need to get under the car to figure out exactly where the sound is coming from, to be sure.. but luckily Tony is helping you out since I guess not everyone has a race jack and jackstands like I do..

That is exactly what mine sounds like and the sound in my case is definitely coming from inside the pipe (the pipe is not hitting the car or anything). Tony is sending me a replacement as well so I'll keep you updated. It stinks that this is happening to some of us, but I guess that's how first production runs are sometimes.

The reason the sound goes away once you rev it up some is beause the ART Pipes (and exhaust as a whole I would imagine) vibrate at different intensities at different RPM's. Around 2000 RPMs (or a cold start) they vibrate a lot.. so that's why the rattle is worst there.

Alright, thanks for confirming that it sounds identical to your issue.

Thanks for those thoughts. I have to point out, though, that people have already indicated that different exhausts produce varying amounts of hiss with these ART pipes. So while it may never disappear completely, it sounds like there are some setups that are better at eliminating hiss than others.

I am hoping to hear some other cars with ART pipes and aftermarket CBEs. I'm interested to see what Motordyne comes up with on the exhaust front, but whatever it is will probably be too loud for my tastes anyway.