Sort of a weird question, but please bear with me.

Is there anyone making test pipes or high flow cats with *two* resonators? Obviously, high-flow cats automatically have one chamber in the first part of the pipe since that's where the cat goes. However, the second half of the pipe is just straight.

On the aftermarket resonated test pipes that are available, there is one chamber in the first half of the pipe, but again the second half of the pipe is just straight.

In comparison, the stock cat pipes basically have two resonators, each one containing a cat.

My reason for asking is that I have Kinetix high-flow cats and a Nismo exhaust. With those cats, the Nismo has a terrible droning on the freeway. Everyone I've talked to says the Nismo only has this droning if you use high flow cats or test pipes. I'm assuming that is due to the stock cats' increased resonance capability over test pipes and high-flow cats.

So, it seems it would be desireable if someone made a set of high flow cats with a resonator added to the latter half of the pipe... or even resonated test pipes with *two* resonators instead of one. Seems like a setup such as this wouldn't increase the loudness of your exhaust quite so much.

I suppose an alternative would be to just gut out the stock cats, since that basically results in a double resonator test pipe. Or you could just gut the 2nd cat, and leave the first intact. (That would still allow for a bit of air cleaning, which is nice.) However, I'd rather not mess with my stock cats. I might be up for it if I can find a set used, though.

 

bump

 

i saw a pair of gutted stock cats for sale on this site recently.

 

Yeah, that's what I'm considering trying. I just found someone selling a set of stock cats for a good price, so I might just grab those and gut them... just to see how it sounds. I set of pre-gutted oem cats would certainly be easier, though.

 

I owned Ultimate Cats and now Crawford. Both sound much better than the RTs I started with. I don't have the droning anymore you're mentioning with my Nismo exhaust. I'm very happy with sound.

 

even with 2 resonators, they will probably have worse "droning" than the hi-flow cats.

Especially since the resonator on the bottom section would be so short.

I would say, possibly have 2 resonators welded into your y-pipe section, then you could put a decent size resonator in there.

 

What about the idea of gutted stock cats? It seems that normal stock cats quiet down the exhaust quite a bit, so would gutting them increase the sound *that* much? Even more than high flow cats? I've got the Kinetix cats, and my Nismo drones really, really loudly on the freeway.

 

TEST PIPE SOUND CLIPS

If you want to hear a sound clip of the Alphawerks Racing Development test pipes you can go to:

http://www.nexusindustry.com/alpha_frameset_main.htm

1. Click on "DYNOS" section
2. Click on "NISSAN 350Z (TEST PIPES) Video Clip"

There we have two sound clips of a 350Z with the Alphawerks Racing Development test pipes and an HKS exhaust on the dyno.

It does not have any sound problems as you will be able to tell when you go to the clip.

Enjoy,
Victor D.
Nexus Industry

 

nice... i dont here any rasp w/ ur testpipes?

 

Moved.