To start off, let me first say that i am currently runnnig a Stage 2 Stillen Supercharger on an 5AT 2006 Coupe. Just so that i am not told this question is too vague to answer.


Right now, my issue is this raspy/clanky noise i am getting from my exhaust, when going over 3500 rpms. Let me explain the combination of systems i have been running.

Stock Cats, Stillen Cat back exhaust = No rasp
Stup Test pipes, HKS cat back exhaust = LOTS of rasp
ART V2 Pipes, HKS Cat back exhaust = Plenty of rasp, less than above
Fast Intentions RESONATED test pipes, HKS Cat Back = Same amount of rasp as above
Current: Fast Intentions Resonated Pipes, Stillen Cat Back = Less rasp, but still plenty.

The installer who installed the exhaust systems told me that test pipes always cause that sound. I have personally sat in a car with one of the above setups and it does NOT have any type of off noise like mine. Also, i have seen PLENTY of videos on youtube from cars running the same exhaust setups (minus the supercharger) and they do not have that sound.

The guy says the reason between the difference in sound between theirs and mine is because of A. Being 5AT and B. Having the supercharger.

When i removed the ART pipes from my car, i had a leak on the passenger pipe.



I havent checked the FI pipes to see if they are leaking.

I dont have a video right now cuz i am at work, but when i get home i will attempt to make one. The best way i can describe the noise is the same nasty sound you hear when a rice Honda passes by.

What do you guys believe can be the cause of this? Some of my local club members know what the sound is like, and probably can describe it better.

 

I think its the testpipes. I have that raspy sound on my vortech supercharger also. When the supercharger is not connected the rasp is even louder. I have resonated testpipes by the way. Thinking about going back to stock cats.

 

I'm thinking about trying the his exhaust with the stock cats. I just want to know exactly what is causing this noise. Something doesn't feel right about everything. I get the exact same sound from both the fast intention test pipes, as well as the art pipes, and in theory, they are 2 completely different sounds.

 

I feel your pain. I had the stock exhaust, and when added ART pipes it brought on the rasp.

Now I have a custom exhaust setup and there's no rasp at all. It's just certain exhaust combinations that cause it, not necessarily the test pipes/ART pipes. It seems like the extra flow gained by removing the stock cat's can cause it some situations. I had my car up on the lift with my old setup and you could hear it coming from where the Y-pipe merges.

For your situation, I would maybe try adding an X-pipe to the HKS. I bet it's coming from where the H-pipe is.

 

A fellow driver told me to modify the hks exhaust a certain way, and that it would remove all noises. But I don't see the point in doing that. It's just depreciating the value of a good exhaust without the assurance that it will cure the issue. I thought switching to the art pipes and the fast intentions pipes would fix the sound, but it's bad man.

 

I haven't heard of one person ever saying they thought the HKS sounded worse after adding the X-pipe... I'd say do it. You shouldn't have any problem selling it on here after the mod. You really only have 3 choices:

1. Use stock cats, lose performance
2. Modify current exhausts
3. Buy a new exhaust

I'd pick #2 or #3

 

If the sound you're hearing is a metallic pinging/faint clank with some rasp under load from 2800-3500rpms, then it's the nature of the VQ. Even VQ30s make this noise when you open up the exhaust. Remove the cats and the noise becomes very obvious. The sound is most often incorrectly diagnosed as a loose or broken internal exhaust part. This is definitely not the case.

If you want to reduce the metallic sound, you're going to need to put in resonators or a cats. Cats act like mufflers.

 

I developed the perfect adjective to describe the noise i am hearing:


FART CAN.

Yea thats exactly how i hear it. From 3500 +. Sounds exactly the same in manual mode than it does in auto mode. Its definitely coming more from the rear than anything else. At first i always thought that it was my license plate rattling, but its too loud for that.

Also, dotn know if this is relevant, but this morning and yesterday, when i cold started my car, i had a lot more smoke coming from the passenger side exhaust (same side as the original leak) than the driver side. Also, even when its not cold, the car apparently spews more out throguh that side, as the bumper was foggy on that side and not the other.


Dont know if this helps or worsens the situation.

 

I don't have rasp now at any rpm... And it sounded like a fart can before at 2500 rpm. Definitely was the stock exhaust.

 

Well, i took a video of being inside the car. Dropped it into manual and tried to bring out the noise. Its really out of hand. I cant stand it.

http://s302.photobucket.com/albums/n...=VIDEO0012.mp4

 

Yup, sounds similar to what I had. Here's a vid I made of the old setup:

http://imageshack.us/clip/my-videos/94/b2j.mp4/

 

I'm curious you havent mentioned the y pipe. are you switching this out as well as you go through certain setups? I just found out my rasp was from a large diameter pipe meeting a smaller one.

 

So far my Y pipe is stock. I want to avoid buy more crap at all costs. I dont want to be like "This will fix it" like i did with the Art pipes, and then be let down and have to lose out on that money.

Ryanm8, what did you do to fix it? Mine sounds like yours, but multiplied by 10.

 

I have a full custom exhaust now. I'm pretty sure it's your y-pipe that's the problem. That's where the sound was coming from before for me. The stock y-pipe goes from dual 2.25" to a merge point of single 2.5". My new one starts off at 2.5" and merges into an x-pipe and stays dual afterwards. Much greater flow, and my rasp was gone.

 

I might consider this, though i need a trustworthy shop down here for that. For now, im just going to see what i can work with, if i can do anything at all.