ok I have DC headers nismo exhaust and Kinetix HF cats anything can do about this rasp sound?

 

Or anything to cut back on it?

 

Crawford cats . I went from RT cats , to La Bree resonated Pipes , finally to Crawford cats...No rasp . I couldnt stand the rasp myself . The La Bree's got rid of a little..not much . The RT's had bad rasp....and collapsed...Crawfords the way to go

 

I have dc headers, CRAWFORD CATS, jic ypipe, japtrix mix pipe, and I still have the rasp...any suggestions? I had the same problem with the magnaflow exhaust...

 

collapsed? how long did it take for this to happen?

 

have a resonator welded into your midpipe

 

The japtrix mid pipe has a resonator on it. I'm wondering if the sound will change when my sc goes on. What do you guys think?

 

custom y-pipe with twin resonators

aside from the nismo exhaust. so far i have experienced that there will not be any rasp as long as you have an aftermarket exhaust. i have heard, the borla, greddy, stillen, fujitsubo, power enterprise, and some more that have either headers and cats or test pipes, and they dont have rasp.

 

that's funny, there is another thread that says just the opposite, that a/m exhaust is the cause of the rasp.

 

yup thats what i read as well

 

well, i believe that the stock exhaust was not made to handle the extra flow of the gasses as soon as we open up the restrictions like the headers and cats/test pipes. so in a way, the stock exhaust is more baffled to quiet everything down, that is, until a high flow of exhaust hits those baffles. when that does happen, i think it creates sort of a resonant frequency that causes the rasp.

now, when you unrestrict the actual exhaust (y-pipe back) with a bigger opening. first, you create less restriction and the aftermarket exhausts were designed to take that sort of flow.

here are some vids:
this car has headers/test pipes/greddy exhaust:
http://islide.net/z33/dynoday1/vids/...%20nitrous.wmv

compared to my car with just stock exhaust and headers:
http://islide.net/z33/dynoday1/vids/...%20daytona.wmv

you can tell i have a bit more rasp with my stock exhaust vs his. and yet he is running test pipes on top of the headers.

i dunno tho, its just my opinion

 

Try putting back your stock cats. I noticed the rasp when I installed my hi-flows.

 

The rasp comes from no cats. I had rasp after removing the cats and after I put on my headers it was unbearable. I added a second resonator and it sounds a lot better now.

 

I have seen with several of my customers a few things.

Generally, even when they have very aggressive exhausts like the Injen, etc. they use them with our hi-flow cats and have no rasp at all.

The only times they have suffered from rasp is when they couple them with aftermarket headers.

One of my recent customers even had problems with the rasp with stock exhaust, but he had hi-flows and aftermarket headers.

 

so does anyone have rasp free exhaust with aftermarket headers....

 

There seems to be a few combos out there that are working...I'm in the same boat. Check out:

http://www.350zmotoring.com/forums/s...5&pagenumber=1

 

Kinetix cats + stock exhasut = no rasp

Cats + NFC Y-Pipe = no rasp (nice sound!)

DC Headers + cats + Y Pipe = huge rasp! Checked for air leaks none. Rasp almost seemed to get worse as the weeks progressed

DC Headers + stock cats + Y Pipe = wow, I can actually hear the engine again! Zero rasp.

 

I PM'd Zboater and he does not have rasp with:

Nismo headers+Kinetix Cats+Nismo Exhaust

Go figure why the headers would make it on yours and not his...is it possible the outlet diameter of the DC's doesn't match up with the cats as well as the Nismo's creating a turbulent area? That or maybe they just flow better.

 

Did you notice any power drop off when going back to stock cats? Also, does it still sound better/louder than stock?

 

I have TopSpeed headers and Nismo catback. No rasp.

What other exhaust elements can I add and still have zero rasp?