i never had this problem when i first install the y-pipe. recently i had to take it off because CA smog check. last nite i put it back on and now i get this horrible rattling underneath the car. sounds like coming from the cat. i checked it and there's about at least 1-2in space between the heat shield and the cat. what could possibly go wrong? all nuts are tightened.

bump, anyone?

Did you check the rear hanger on the B pipe? Did you put in a new gasket or at least make sure the old one was seated properly?

It has been a few years since I installed mine but I remember having the same exact thing. I beleive it was at the cat. I remember a the heat shield or something was hittng the car while it vibrated. I'm sorry I can't remember more without looking under the car. But I remember I got under and just shook the heck out of the Y and it was obvious what was hitting. I need a smog (CA) very soon. Do you strongly recommend taking my Y off first? Thanks and good luck.

Ive heard that you can still pass if you let your car warm up before getting the test done. I wouldnt think that you would have to take it off.

the b-pipe is definetly hanging properly. yes i put all gasket in. everything is sealed correctly.


i guess i was a bit paranoid that's why i took it off. i did't wanna risk extra $70. when the perform their visual inspection, they only look at the cat, not that pre-cat. as long the cat exist, they'll let it go. they don't care about the muffler either. but they do care about intake and header without CARB. you mite wanna be aware of that.

one guy happened to failed smog with the y-pipe on. but most people pass with the y-pipe on (hakk97se, nadir_s, etc..). just keep up your basic maintance then you should be fine.

I have the same sorta sound coming from my y-pipe, i looked at the y-pipe and it looks like when the motor moves alittle, it moves enough to make the pipe hit the "tunnel." I'm going to wrap it with exhaust wrap, and hopefully it sould get rid of some of the rattles i get.

If you put it up on a lift, apply the brakes very hard, and slightly rev the motor in drive (putting load on all components, simply reving the car will not do this) you will see why you need a flex section in your Y-pipe.

I had this exact same problem, did the above and noticed where the pipe was hitting. After I moved everything out of the way it was fine.

warpspeed does have a flex section, what do u mean?

what do you mean by "moved everything out of the way"?

i can almost gaurentee is its the hanger between the cat and the y-pipe. There are two little prongs, bend those and you should be fine.

i bend them already. it's not touching the flex section but it's very close to it. i can't bend it anymore. any other solution?

I mean that it is clear when the car is put underload why a flex section on a Y-Pipe is needed (as in the Y-pipe moves around a lot, I know that all y pipes have this, I was only emphasizing that it moves a lot.)

Bend the heat shield, cut off any uneeded pieces in the way etc.

i already took off the two little prongs between the cat and the y-pipe. yet the rattling + cricket got worse. i will take off the heat shield and then get an exhaust wrap and jus wrap around the flex section. i'll keep you guys posted.

the only thing that's frustrating me is i didn't have to go through it the first time i installed the y-pipe. now all these problems came up and it's killing me. but eventually i'll deal with it just like any other mods i've done.