Rasp Galore?

[Diokaef]

I know but in my experience the headers is causing 90% of your rasp so putting resonators is like putting bandaids in bazooka holes. I tried all the systems on the market, so I know that your headers is the killer. the S-pipe just cause to be released on to open air and the x-pipe just going to make things worse. You should consider AA headers with the setup that you want to run since it will most likely sound better then even SS headers.

[mfanatic325]

hehe, not going to swap my headers now. Too late at this point. Plus, I got my JVT's for free, and did the work myself, so it's double or triple worthwhile
I'm thinking of swapping my SS section1 with someone for their stock section1, then cutting off the rear two cats and replace with resonators. They'll hafta pay cash on top of course. I really don't want to cut into this quality piece of SS engineering hah.

[Diokaef]

You Know you have other option coming soon right?? maybe just maybe you should hang on for a bit with what you got... just a friendly advice...

But anyways I wish you luck on solving the issue.

[mfanatic325]

haha budgeeeet! Can't break the wallet more than it already is

[pokeybritches]

Originally Posted by mfanatic325

or if I have a hot date or something lolol

Is there any other kind?

[onebluemcm]

Nice vids - depicts the rasp pretty well. Now it sounds like my M3 did. That is why I do not agree that it's the headers - my M3 sounded like you car now with stock everything.

First, the "rasp" you car is making almost sounds mechanical, like a vibration. I'd first double check installation. Second, if you are hearing a "hiss" sound at all, there is anexhaust leak somewhere, so again I'd just run over the system, check installation.

The rasp noise is worst in a specific rpm range, as far as I can tell from the vids. This is because of harmonic resonance that is occurring - this is why you need resonators. For whatever reason, the sounds and gas pulses are resulting in bad harmonics that vibrate the whole system and make the rasp in that specific rpm range - this is how the rasp occurs. I think it has to be due to Section 1 - as you may know, the M3s didn't have secondary cats, at least my '04 didn't. Only one pipe in the M3 section 1 had a puny little resonator. The M3 and Z4M stock headers are essentially identical but it's section 1 that varies a lot between the two cars and stock, the M3 has way more rasp than the Z4M stock.

You must resonate the system. If you remove the resonator in the x-pipe by going to the SS x-pipe it will probably be even worse. As for cutting out the cats on section 1, it may be trickier than it appears - the pipes leading into the cats are not a standard diameter but are custom pieces that gradually enlarge. You have to cut it way forward in the section before the pipes enlarge and then fab up the rear part from scratch. Because a stock section 1 costs so much to replace, there is some incentive I could see to not bastardizing your stock section 1.

Honestly, best thing is probably to find a good, reputable exhaust shop and get a custom section 1 made with resonators. If it's hard to fit them side by side, they could be potentially offset from each other, one ahead of the other in opposite pipes.

I am a rasp hater too, and that was one thing that drove me nuts about the M3 as well. I'm a little concerned that swapping my US headers for euro headers will bring some of it back, so I feel your pain. Knowing that I'm keeping the stock section 1, I am a little at ease though because I am rather certain that it's the loss of cats in section 1 that would result in bad rasp. If you haven't checked out Jack's stuff at Custom Performance he has worked some wonders on M3 systems to get them sounding great and rasp free. You might just call him to pick his brain on what to do or not do.

[inTgr8r]

Originally Posted by mfanatic325

[B]

BTW, my current exhaust mods are (in order): JVT headers, SS section1, stock section2, SS race mufflers.

...so with headers & the catless SS, you're completely catless?
That's got to be a challenge to get rid of the rasp.

subscribed for further results. (not a rasp fan either)

[onebluemcm]

http://www.m3forum.net/m3forum/showthread.php?t=350154

This is what we need. I may be able to be a test mule for Jack, he's only about 45 miles away from me - it's just the fact that I have very little free time....and Jack has a ton on his plate with the M3 crowd...

[Nate2046]

Originally Posted by onebluemcm

First, the "rasp" you car is making almost sounds mechanical, like a vibration. I'd first double check installation.

Agreed, sounds like something is rattling. Double check and make sure nothing is touching, heat shields, etc.

[ZStig]

def something rattling in your setup. Probably an easy fix

[inTgr8r]

Originally Posted by onebluemcm

http://www.m3forum.net/m3forum/showthread.php?t=350154

This is what we need. I may be able to be a test mule for Jack, he's only about 45 miles away from me - it's just the fact that I have very little free time....and Jack has a ton on his plate with the M3 crowd...

wow... nice pipes

[mfanatic325]

Yeah, my heat shield is probably hitting somewhere. I had to push it back once already. I probably also need to tighten the two bungs that come with the SS section 1.
Also, I probably could tighten the junction between the headers and the S-Pipe more. I figured I was going to take everything out again once my X-Pipe comes in, so I kind ofjust make it tight "enough" lolll half-assed it sorta.

Wow Jack's pipes look amazing! Those are meant for E46 M3's, correct? Damn, wish I could obtain something like that for our cars. I'd sell my SS section1 in an instant for a no-rasp option =P

I would rather cut up a second set of OE section 1's for a custom resonator fitting than to use my own Just in case Cali decides to poke me in the ass like a prison convict

[eunosracr]

I think i will be adding resonators this weekend too. My AA headers, RE X Pipe and Meisterschaft cans combination is loud as all hell.

[onebluemcm]

Originally Posted by eunosracr

I think i will be adding resonators this weekend too. My AA headers, RE X Pipe and Meisterschaft cans combination is loud as all hell.

And you have a stock section 1?

[eunosracr]

Yep. Stock section one the S looking pipes.

[cmark8]

Only stock section in my car is section 1 and I usually have a hard time finding some peace in my car. When the pipes are cold I get this really annoying buzz, but when everything is nice and warm, it sounds very nice and raspy. So Lon, chill and you'll get used to it...

[mfanatic325]

lol NEVAR! I'll get rid of this rasp, even if it kills me

[ZStig]

fix the damn rattle!

[mfanatic325]

I don't hear any other sounds beside the rasp though. And it only hisses when I come to a stop, which I'm guessing is because I didn't tighten the junction between headers and section1 all that tightly.

[eunosracr]

Let me know if any of you guys get the rasp eliminators to fit. I went to a muffler shop today and they said there is no space in our cars. Oh well.

[ZStig]

try welding a small bracket between your exhaust pipes

[mfanatic325]

Originally Posted by Roffle Waffle

try welding a small bracket between your exhaust pipes

But my pipes aren't rattling at all at the moment. Everything seems tight. The only complaint I have is the raspiness, which is purely engine harmonics. And pretty much the only thing I can do is readdress the section1 piping; whether it be doing some custom work in resonating one or two of the pipes or buying a whole new setup altogether. We'll see.
For now I'll try to live with it. At least it's not all nasty @ higher RPMs, which is where I'll be anyway for track.