I just installed the Rt cats and it now has atasp to it @2500 to 3000 rpm. So probably the cats are the reason for the rasp wich is not a problem it only means you have not had your car tuned since you installed the cats. Reason being with high flow cats you have less back presure witch results in running rich and less HP.To get the most out of your mods for the z33 you must flash and tune your ECU . You can try TECHNOSQUARE.COM

 

Resonators cure the rasp, and you don't have to spend $600 to get the technosquare flash which i doubt will cure the rasp. If you would have botherred to read the thread you would see that KISS solved his rasp issue with resonators, as did I

 

& so did i. i was the first person who ever mentioned the kinetix resonated test pipes(resonators in general actually). i even posted how they did the research & designed thier resonated pipes just for this reason. its funny, if you look back to when i first started replying you can see i was touching on this very issue but noone was listening. then when somone finally responded to what i was saying there was an argument about how wrong i was & thst there was still a major problem..........just funny how everyone is now going the resonator route, lol! im glad that somone had started applying thier own resonators to thier testpipes to save from overspending to eliminate the rasp. i still highly recommend the kinetix resonated pipes for those that have not went with test pipes yet. it will be about the same as if you purchase non resonated pipes & add your own resonators, just easier from the get go...............good luck!

-justin

 

Has anyone tried Nismo's cats to see if it has the same rasp problem as the other cats/test pipes?

 

ANT

Take a look at how chapparo78 solved his rasp problem .Lots of pics.

 

Moved.

 

Well, although this is not related directly to the topic, I had a vibration coming from the rear of the car at around 1.8 - 2k after installing a y-pipe and resonated test pipes (stock exhaust). It also made some strange noises at higher RPM's under WOT. I later swapped the test pipes out for hi-flow cats (for other reasons) and the vibration was still there.

Well it turns out it was the thin flimsy V-shaped air shield that is bolted onto the stock muffler. Everything was nice and tight, but apparently it's so thin that it just naturally resonates at those frequencies or something...?

So I ripped it off and the sound is gone. I don't really think the shield did much for airflow anyway, the stock muffler is already pretty oval in shape, you would probably have to be going 150 for it to make much difference.

 

You have any pics of that V shaped shield? Btw, what is "rasp"? I have a sound that sounds like a metal on metal vibration. This appeared with the install of my Stillen Test Pipes. Is this Rasp and would resonators cure them?

Also, where can I find a good muffler shop in FL?

 

I read all ten pages of this thread and I seem to be the only one with this setup...

TopSpeed Headers and Kinetix HF Cats.

I have the rasp at 3-4k rpm at WOT and wonder if anyone knows if replacing the HF Cats with resontated test pipes will improve or worsen this?

 

bump wondering the same thing

 

BINGO! You get the gold ring, richie!
If the very manufacturer of our cars says the rasp is normal with their very own hf cats, then there's not much more to be said, imo, other than to find a type/brand of rasp you can live with for the gains produced, and move on to cracking the great ecu mystery!

 

most of you guys were talking about the test pipes. Don't the high flow cats have resonators on them?

 

I have ultimate racing hfc's and I'm getting the buzz. Shouldn't these be better than test pipes or even resonated test pipes?

 

bump

 

i have topspeed headers and kinetix HFC..and i do have that metal on metal ringing at certain rpm's (3-4)..its damn annoying and im thinking bout putting my stock cats back on and seeing if the problem is solved..ill post when i do

 

I'm going to be putting my car up on jack stands this weekend to see if its making a conection on the drivers side with the heat shield

 

i have the titek test pipes and im getting the rattling sound also. i checked underneath and i think its the flex pipes thats making the sound.

 

what are flex pipes?

 

let's bump an old a$$ thread why don't we...

the clip below is of my Z with *AAM test pipes & y-pipe, stock mid-pipe without the resonator and stock muffler. So I've read this thread and it's the only one with a distinct title to my problem.



BUZZING!

I don't mind rasp however much but this buzzing noise is killing me...

I might have an exhaust leak, cause I was excited while installing it so I might not have tighten down everything. I removed the metal heat shields above the muffler and the two over the test pipes. There is one more over the mid-pipe, I'm planning to remove it as well seeing that it might be it vibrating...
So in short I think it might be either of the following with my setup.

- mid-pipe without the resonator
- last heat shield over the mid-pipe
- chambers in the muffler itself

really don't want to ditch this parts due to the sound...cause the instant felt change it power was great...

EDIT:

Also the buzzing is from the very rear no where near the test pipes.

 

Sounds to me like rasp and metal vibration. I'm sure once the system heats up and it dissapates. Mine does have rasp when cold, once warmed up sounds very deep and just awesome, like an exhaust should sound.