sry110

iTrader: (17)

Two weekends ago we installed a JIC y-pipe and Fujitsubo Legalis-R exhaust system onto my Z. I bought these items used from another member on the boards. I believe in his 'For Sale' thread he stated that they had been on his car for about 15,000 miles at the time he put them up for sale. Anyways over the past week or so I have noticed a horrendous noise that occurs when I first start the car and rev it while the piping is still relatively cool. It sounds like a crazy rodent or bird or something, but I'm pretty sure that more realistically it has to do with some piece(s) of metal flapping around and making this abrasive sound. It seems to go away (or at least become inaudible from inside the cabin) once the car is run for a while and the pipes heat up. Take a listen to this sound clip I made tonight and let me know if you have any ideas as to what may be causing this sound...? BTW in case you have trouble hearing it (although I think you'll notice...) the sound first happens around 11.5 seconds into the video clip right after I start the car, then you can hear it during the coast down of each subsequent rev.

http://home.comcast.net/~steve.yemenijian/Z_exhaust.MOV

After watching the video again myself, I just noticed somewhat of a hissing sound that seems to happen right when that other crazy sounds happens. WTF mate???

Also, I have noticed a repetive clicking sound coming from underneath the car while driving ever since installing this exhaust. It is especially noticeable if I am driving alongside a curb or next to a concrete barrier, both of which tend to reflect the sound from under the car up through the open window and at my ears. Not *click click click* but more like *clickclickclickclickclickclick* you get the idea. Any clues as to what that one could be? I'm starting to feel like I got screwed on this deal...

Thanks in advance for any helpful input.
-Steve

doskiez

All gaskets in bolts tight and so forth? If so then it sounds like there might be a hole in one of the pipes that is in effect creating a whistle, or maybe there is a baffle that is lose inside the muffler. I would suggest taking the exhaust off inspecting it shaking it to see if anything is lose and maybe pressure testing it to find a leak, pay attention to the flex joints on the y pipe (if equipped) and all the welds for the hangers and connections between pipe and muffler, resonator, hangers, etc.
Good luck

jondimellow

iTrader: (3)

also make sure that ure pipes (near y-pipe and mid-pipe joint) isn't touching the metal supports that stiffens the frame.

mchapman

iTrader: (1)

Without listening to the sound file sounds like you have an exhaust leak.

Could be at one of the joints or a small crack in one of the welds. When its cold the metal is contracted causing the crack to be larger. Take it to an mechanic or exhaust shop with welding equipment incase its at one of the welds. They can put smoke through your exhaust and block off your muffler and look for the smoke to exit via the leak then fix it.

Blue_Streek

iTrader: (3)

thats typical in the y-pipe area. the flex joints are hissing because they do not have a really good seal. do you have HF cats/TPs? if so the problem is amplified. thats the reason why i got rid of my aftermarket y-pipe, it hissed way too much with my TPs.


tommy

edit...after hearing that, it sounds like a nice leak.

plumpzz

iTrader: (10)

The hiss is normal with Tp's and a larger Y pipe. Its especially bad when ur driving next to a wall while downshifting. Ive had it w/ 3 exhaust setups

sry110

iTrader: (17)

Thanks everyone for your suggestions. However while everyone has addressed the hissing sound, not too many have offered any ideas on the squealing / squeaking / banshee noise that I was most concerned with. Any further ideas on that specifically?

sry110

iTrader: (17)

I was thinking some more about that loud squeak / squeal that I am hearing when I rev the car while the pipes are cold. It kind of sounds like a metal on metal squeak, and it seems to be coming from closer to the front of the car. I am thinking that maybe the fasteners holding the cats to the y-pipe have come loose a bit since I installed the y-pipe two weeks ago, and so when the car is cold (and the pipes are at their smallest length) there is a gap created between the flanges on the y-pipe and the flanges on the cat, so exhaust gas is leaking out at those points. I am thinking that a gap there explains the hissing sound which is indicative of a leak, and the squealing / scraping sound is caused by the exhaust gas passing through the loose gaskets at the cat to y-pipe connections at a high velocity. Each of those flanged connections has 3 or 4 really thin gaskets and I can picture them flapping around and making noise if they aren't properly sandwiched in there.

Before I get under the car again, does this sound like a reasonable explanation of why the car is making the sounds in the video clip?