A few weeks ago I bought a set of cnt hfc's and soon after a nismo cat-back that I bought used from another member. I received the hfc's a week earlier so I installed those first. Sounded a little raspy because of the mismatched sizes, but not too terrible. Friday I installed the cat-back. I am just not happy with the sound. It is much deeper which I like, but also still has a lot of raspiness and seems very loud. Has anyone else experienced this? Everything I have read indicates everyone loves the sound with similar combos. Do you guys think a resonated xyz would help?

 

i had kinetix resonated test pipes with my nismo setup and i loved it. absolutely no rasp

 

I'm running a Nismo cat back.I added Kinetix resonated test pipes soon after I installed the Nismo.Sounds good to me.I have few friends that were running straight test pipes.
Others with HFC'S of different brands.Most had the usual rasp.The resonated pipes
eliminated most of the rasp.Possibly buying used stuff is the problem?

 

Is it possible for something to be broken? The guy did kinda lie to me about it. Looked like the resonator had been rewelded or replaced.

 

The substrates on the inside could of been gutted. Shine a flashlight down and see if its damaged. But try a combination of S Tune and Berks HFC

http://www.youtube.com/watch?v=9pvPM..._order&list=UL

 

what y pipe are you using? If you are using stock y pipe, that could be the reason for so much rasp.

 

Using nismo y pipe.

 

Do you mean the muffler? Im not sure how I would see in it, but it looks ok from outside. Resonator had been rewelded back onto the midpipe. It is strait through though so Idk how that would affect much. Does anyone have a close up of the nismo resonator so I can tell if it is the original? Does it say nismo or anything?

 

Maybe I am just being too picky. I took it for a drive and took it through the rpm's a little more. It just seems like between ~2.5k and 3k rpm's is has sort of a loud raspy tone. Everywhere else really isn't bad. I wish I could hear another one in person. It sounds somewhat like Itzcashew's video, but with a loud spot right after low shifts. I do like how it sounds at higher rpm's. Not terribly loud, and nice and deep and throaty.

 

That is actually normal in the 2.5k~3k range. Try letting the exhaust and engine warming up completely then drive it through the gears. On my M2 exhaust, when its cold the exhaust is raspy. If you give it time it could just go away.

And about the resonator, take a pic of what yours look like so we get an idea of what you mean.

 

It does seem to get a little better when after everything has time to get nice and hot. Now that im getting used to it I like the way it sounds. Do you guys think a resonated xyz will help the sound at all?

Ill take pictures when I get the chance. Idk if it is possible without lifting the car. I might have to wait until the weekend when I have access to a lift.

 

http://www.youtube.com/watch?v=BibJZ7mcrXA
cousins S Tune nismo with M2 Y pipe and Berks 300cell HFC SKIP to 30:
at least you guys don't have a ball sack sound like mines...

 

Not bad. I can't wait to get mine on a dyno. Im not sure if I am just getting used to it or if it is physically changing but it is starting to sound better to me. I think I am still going to get a xyz pipe. Hopefully it will remove some of that 2.5k rasp. Also I am worried about my cats breaking. The nismo y seems very tight. I just hate spending more money on the exhaust. I was hoping to start putting money elsewhere, like an lsd and maybe lower final drive. Oh well.

How much is a used nismo y with a slightly torn flex pipe worth?

 

Slightly torn flex pipe? and you're wondering where your rasp came from? Double and triple check the "slightness" of the tear...I'd say that could easily cause some rasp. I'd make sure it wasn't leaking at all before I dropped more money in it.

Regardless, I'd say you're bound to find some rasp somewhere in your rpm range no matter what you do. Cleanest I've seem to find is the motordyne...I plan to run their shockwave v2 exhaust with straight test pipes so I do expect to have a little.

 

I hadn't thought much about the flex pipe I guess. Everything is still intact, but there is a hole through the mesh. I didn't think anything was leaking, but maybe I had better check again.

This is one of the things the previous owner lied about. The pictures definitely didn't show any tears.

 

Not to say it could be the root cause of all of the rasp, but I'd say if there's a hole it's definitely contributing. HFCs and test pipes are going to cause some, but most of the nismo exhaust + HFCs/test pipes clips I've watches seemed to sound smooth with little to no rasp.

 

SAME problem here!
I had the Nismo cat-back with a megan y-pipe (don't ask), strup headers and aam high flow cats. I had a good bit of rasp and a local exhaust guy suspected a "leak" at the y-pipe. Repair attempts=no success.

For the sake of better sound I put the stock y-pipe back on and now I have rasp from 2-3k and sometimes higher-up in the rpm depending on exhaust temps.

Lots of searching has yielded no solution.

I like the stock Z sound and just wanted a better flowing system that sounded like a Z but a bit more aggressive.

I was wondering whether or not a resonated y-pipe would solve the problem or not.

 

I plan to buy one soon so I will definitely post my results. Money is tight with school, so saving the extra money may take a couple weeks. I'm sure the motordyne would be a huge improvement over the megan y pipe.

I wouldn't expect it to sound like stock, or be anywhere as quiet. I have never heard a performance exhaust system that I would consider quiet. If there was a easy way to make free flowing exhausts quiet, auto manufactures would already be using it. My only problem is the raspy sound around 2.5k.



I did reach my hand under the car to check for leaks the other day. The only spot I could feel leaking was between the driver side of the y pipe and cat. It was actually fairly bad. I tightened the bolts a little more, but it still has a small leak. It seems to sound a little better, but at higher rpms I think I can hear it leaking. Less rasp now though. I'm worried maybe the gasket was messed up during installation. The gasket came with the hfc's so it has been been taken off once. I guess it can't hurt to try high temp sealant to see if it helps. I am worried about the fitment of the nismo y pipe after finding this leak. I know there is a problems with it causing the cat's to crack. Mine do have pretty solid hangers, so hopefully it won't cause a problem. It may be worth it to get the xyz pipe, just so I don't worry about breaking anything.

 

i had nismo exhaust with kintetix resonated test pipes. it was the best sound in teh world, best ive heard on a Z and i heard it all. Until the test pipes cracked. Never had that hiss or rasp until the crack.