Recently I put catless test pipes on my 09' coupe, and the next day I hit a dip in the road and broke my flex on my megans y-pipe so I ordered a new one. I put the new one on and with the catless test pipes going into the megan y-pipe on down revs there is a very loud hissing/ rattling kind of noise. I thought it was an exhaust leak so I got another gasket and put it up on the lift, and NO exhaust leak. It seems to me the noise is coming from within the new flex pipes. Anybody ever had this issue or now how I can fix it? I cant figure it out!!

 

Perfectly normal. Search on the forums here and on YouTube.

 

By chance, does the hiss sound like this on my car?


The hiss is present on deceleration or heavy acceleration. If so, its normal.

Latez

 

yes it sounds just like that but way louder. I've come to find it will become less and less loud and noticeable over time (put a new y pipe on about a month ago) and the noise is normal. Thanks for the response I appreciate it, the noise does bother the hell out of me though lol

 

What is your full exhaust setup currently? I have noticed that cars with mix and matched exahust parts tend to have more rasp then ones with same brand parts. For example, I have ART pipes with full Motordyne catback. The amount of rasp is less on mine than say a car that has ART pipes and ARK exhaust. Your rasp is louder than the one above because of your test pipes. The carbon has probably built up over time and sealed a small leak you might of had.

I would have replaced the Y pipe with the XYZ pipe with resonator from Motordyne. These have good reviews/gains and help more with the rasp. <-Just realized that's what projectpanda13 has above lol

Another thing you could do is try some header wrap. I wrapped my ART pipes then applied DEI high temp spray and it helped reduce my rasp even more.