Well I am going to get my headers installed on this Thursday, and I will definitely post afterwards to see if i can detect exactly where the noise is coming from.

 

I'm dying to hear what you find out!

 

I had the same problem, and it has to do with the engine itself. There is rasp in this engine between 3-4k which is taken care of by the stock cats and resonators. I had the same problem when I put on the helix pipes with the stock resonators. But since I put on my exhaust I have literally no rasp at all. I think this is mostly due to the fact that the injen exhaust has a resonator on each pipe. A friend of mine has race pipes on his altima and a single to dual custom exhaust similar to the nismo. In order to get rid of the rasp, his performance shop modifies a resonator from a ferrari that cost him like $350 (normally $900) which took care of the rasp with a single midpipe exhaust setup.

 

nevermind...

 

Has anyone tried putting the stock cat back system back on to see if the lack of a tuned resonator in the middle pipe is in fact the cause of the problem?

 

I had the OEM muffler/resinator, RT Cats and JIC Y-Pipe and had the "buzzing" sound. I just installed a Fujitsubo Y-Pipe back exhaust tonight and it's still there.

 

Obviously you didn't read what I said 2 posts ago.

 

Did you install the headers? Figure out where the rattle is coming from??

 

I've had Kinetix cats with the stock exhaust and the cats with a Borla. Never had the buzzing, except for the left cat rubbing against the heat shield during med-heavy throttle (engine is twisting in that direction).

 

I have the Borla True Dual with the Kinetixs cats. The ONLY time I have any Rasp is when I get OFF the throttle around 6-7K. It's a very short rasp that quickly disappears as soon as I get bak in the throttle.

My personal opinion is that it has to do with exhaust velocity and / or back pressure.

I LOVE my Kinetixs cats. I can live with a SHORT rasp every once and a while for the performance gains I got!

 

I've had the Injen SES for a while with no problems, and now I have a noise that just developed. My car makes a metalic raspy noise at low rpm (@2000), and under moderate to heavy throttle. And of course it doesn't do it while neutral reving, so I doubt I'll ever find it. I don't think its the Injen, but who knows....

 

I have the Crawfords CATS. I too have the raspiness between 3-4K. More pronounced when cold, but less once warmed up. If gradually accelerating through the rev range, not much of a rasp is noted; however, when WOT, there's definitely a rasp, even when warmed up .

 

Well there goes my possible cold weather theory for the buzzing problem. If you have the same problem in Hawaii, then my much colder weather definetly isn't the cause.

 

Yeah .

 

Does anyone have headers, y-pipe and so on with an Invidia/rsr type exhaust, and STILL have the buzzing? No matter what exhaust is used, it seem this sound is unavoidable. Is this what a race car sounds like? The more you open the exhaust, the more you hear the engine?????

 

Look at the post about 13 back (SCZ), Injen SES Exhaust. He said the buzz is non-existant with his duel resonator exhaust, but does it restrict somewhat?

 

The resonator is what it is, for resonation. I guess the engine is definitly tuned different. I don't think that resonators cause any restriction. Most are wide open pipes with perferated materials. I guess our cars need this to tune the sound. I have a 88 fiero gt v6 with wide open exhaust, headers, no cats with a flowmaster and it sounds like a v8. I was hoping my car might pick up some v8 characteristics.

 

Yeah. If you heard the JGTC 350Z, it sounds like sh*t. Perhaps it's the nature of the engine.

 

yeah but the NISMO exhaust has a resonator and i still get the noise

 

So you have Kinetix Cats and still you have the sound? I thought this Cat didn't have the rattle. Oh well. Man, I can't believe with all the motorheads on this forum, nobody has solved this. Maybe when I get dyno'd they can check the exhaust under torque load.