Ok so I just bought a new axle back WS2 system to replace the old Apexi N1 exhaust I was running before. The N1 was starting to get very annoying and just wasn't cutting it anymore. So I bought the WS2 and bolted it up. Checked to make sure everything was tight and that every thing cleared the exhaust. The muffler is big but there was still at least a half inch clearance all around the muffler. The tip looked nice and the sound was a bit louder than stock, but still quiet. So I let the car warm up and I take it for a test drive. Well at about 2,500 rpm I hear a faint buzzing/humming sound. then goes away above that until 3,500 rpm when it comes back even louder. Its not a banging sound, more like a quick tight vibration. Its even more annoying when the car is under heavy load in those rpm ranges like when I'm going up a hill. And if I stay right at 3,500 the buzzing is constant. Sounds like its coming right near the passenger side rear section right above the muffler. I made sure my rear bumper was tight and I even took out most of my rear panels trying to find the noise. I checked the muffler before I installed it to make sure there was nothing rattling. Has anyone else had a problem like this with the WS2 exhaust? My N1 didn't cause this much racket.

 

That buzzing and raspyness you hear is generally a normal part of a honda's exhaust note, but if its getting loud and annoying it may be due to two factors :

1. Catalytic converter: Your stock cat, in normal working order, does a decent deal of muffling high pitched to mid range frequencies, such as raspyness and buzzing. Generally, a car without a cat (test pipe, or gutted cat) will have a very raspy buzz to it due to the lack of muffling.

2.) Resonator. A resonator is a larger bulge in the Mid-pipe that is packed with muffling material. It serves as a pre-muffler before the exhaust gas reaches the muffler. Similiar to the CAT, it provides (more) muffling of the sound, reducing high to mid end frequencies, leaving you with a nice lower tone.

Normally the average civic CatBack system will have some buzz or slight raspyness to it, depending on its quality.

Id check to make sure your CAT is in good working order, and then if thats still not enough, ive seen a trend of ppl adding a second resonator in their midpipe, which can significantly reduce the high end sound, leaving you with just a low drone and hum.

 

Forgot to add that I don't have a cat. And the resonator is new too. As for the sounds, I'm not talking about the actual exhaust note that is buzzing or having any raspyness. This noise is apart from the exhaust note. The exhaust note is fine and very quiet compared to the N1 I had before. Now that was raspy and loud. But what I am talking about is some kind of vibration or humming sound. I can hear this humming sound and hear the exhaust note seperately. They are two different sounds. The sounds I'm talking about is a very very high pitched resonating sound much higher than the exhausts sound. Almost sounds like something is just slightly loose like as if the license plate is vibrating.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SeVeNisOnE &raquo;</TD></TR><TR><TD CLASS="quote">Forgot to add that I don't have a cat. And the resonator is new too. As for the sounds, I'm not talking about the actual exhaust note that is buzzing or having any raspyness. This noise is apart from the exhaust note. The exhaust note is fine and very quiet compared to the N1 I had before. Now that was raspy and loud. But what I am talking about is some kind of vibration or humming sound. I can hear this humming sound and hear the exhaust note seperately. They are two different sounds. The sounds I'm talking about is a very very high pitched resonating sound much higher than the exhausts sound. Almost sounds like something is just slightly loose like as if the license plate is vibrating.</TD></TR></TABLE>

Could be a number of things. I would first check to make sure all the bolts are firmly in place along the whole exhaust. Keep in mind a striaght-pipe type of test pipe will cause more vibration down the exhaust line, moreso rather than a testpipe that is like a resonator (cant remember specific brand names).
Aside from all that, are you sure that your exhaust is not touching any part of the underside?

 

is the muffler rubbing on anything

 

I've made sure that there is nothing touching the exhaust. I can put my hand between the muffler and the body of the car all around and all the piping is clear too. Nothing is touching. I'm thinking when I get home from work today I'm going to gut the car out and remove the rear bumper and try to find out what is causing this vibration. Its very annoying.

 

Did you get a good deal on it? Where did you buy it?

 

I got a decent deal on it? $405 shipped.

Well guys the vibration started to get even louder. Sounds like when you get feedback from a microphone. Its louder now and makes this noise at 2000, 2500, 3500, and 4000 rpms. IT IS ANNOYING. I complety gutted out my interior. Didn't take me long. I jacked up the car and made sure everything was tight. Not one thing is touching. So I drive the car gutted and the sound is still there! I get back home and let the car idle. I put me ear about a foot from the muffler and I can slightly hear this high pitched feedback like sound. I shake the muffler and it doesn't hit anything. So I took the muffler off and nothing sounds loose in the actual muffler. I put my old Apexi N1 exhaust back on. Drive it around and the sound is gone, but the car is too loud for me that way. Put the WS2 back on and here goes the humming again. All I was replacing was the over axle piece since the WS2 and the N1 use the same exact piping from the cat back. I got it down to the actual muffler being the culprit. Has anyone else had this problem or is it just me? Anyone dealt with Apexi customer service? I would like to have the muffler replaced.

 

i have Apexi N1 and my piping is like 3in and m was whating to get Apexi ws2 but it has 2.5in piping

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nurvcom &raquo;</TD></TR><TR><TD CLASS="quote">i have Apexi N1 and my piping is like 3in and m was whating to get Apexi ws2 but it has 2.5in piping </TD></TR></TABLE>

And your post helps him how??

 

did you buy the axle back new? It could just be the honeycomb in the muffler is going out, or even some of the packing.

Keep us updated

 

I pm'd you. i Have the same problem. 00 si, ws2 catback, omni testpipe

im pretty sure its the exhaust tip vibrating against the rear bumper at certain rpms. Mine has done this since i bought it. It's spaced away from the bumper. I took my bumper off while it was being repainted and never heard the noise while it was off. Im positive you have the same issue. Take off your rear bumper and take your car out. THe noise will be gone.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by electron_si &raquo;</TD></TR><TR><TD CLASS="quote">I pm'd you. i Have the same problem. 00 si, ws2 catback, omni testpipe

im pretty sure its the exhaust tip vibrating against the rear bumper at certain rpms. Mine has done this since i bought it. It's spaced away from the bumper. I took my bumper off while it was being repainted and never heard the noise while it was off. Im positive you have the same issue. Take off your rear bumper and take your car out. THe noise will be gone. </TD></TR></TABLE>

Exactly what I was thinking.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Probot &raquo;</TD></TR><TR><TD CLASS="quote">is the muffler rubbing on anything</TD></TR></TABLE>
check that^

 

Mine makes the same sound, from 3000-3500 rpms. I have mine in a eg hatch though. It started after i got my swap(b16). I think mine has something to do with the inside of the muffler..

 

I did take the bumper off. After I did that I jacked up the car as high as it would go and check all the piping. Even turned on the car and got under it. I could hear a slight pinging sound coming from the muffler and when I would get closer to the front of the car I could hear the sound in the rear. I even took the whole system off and check to see if there was anything inside of the piping that could be humming, but everything seems tight. So after I took the bumper off I went for a drive and the noise is still there. So its not the bumper rubbing. I'm almost sure its the actual muffler itself. I wouldn't mind trying to get another one under warranty through A'pexi if its not too much of a hassle, but I would be sorely disappointed if I slapped on a new muffler and it made the exact same noise.

 

gaskets not installed properly? excessive amount of material protruding into the way of exhaust gases and under load/higher rpm causes the gasket to vibrate? Just a thought.

 

The Apexi WS is made of three pieces. Make sure the second piece (s bend) is not on backwards.

 

do you have a short shifter?