I was just outside and i noticed my hks exhaust (when on) was making a noise that sounded like air coming out of a tire, but it was coming out of the exhaust. it wasn't constant but its not like the noise would fade, either, it would turn on then off etc....just wanted to know if this was normal or something? I know it's not from my plenum spacer because it's comin out from the bottom. Aiight lmk

 

Unless you've hit the exhaust system it's probably a gasket, take it to your local muffler shop and get it fixed.
Gary

 

You know That reminds me. The shop I went to told me that I didn't have to install these two gaskets yet in the front in between the catalytic converters so maybe I need to switch the stock ones with the ones for my hks exhaust. And yeah I didnt hit it so I hope that solves it. I hope they won't charge me for labor

 

If it sounds like a hissing noise just going off randomly and then stopping for a few seconds an then back on again and it's under your car... It should be normal. My g35c does the same exact thing with the stock exhaust and my Minsk exhaust so I wouldn't worry.

 

Are you sure that's normal? I have two gaskets that I still need to swap in between the stock cat and downpipe because the place I had it installed at told me to use the stock one for now until it wears out. But if others who has an hks stock or another exhaust hear the hiss sound going on and off randomly and say it's normal then I'll take your word for it

 

I would just replace the gasket as my first step of fixing it... rather than playing the guessing game.

 

Mine does it too sometimes, but only when i go from D to Manual mode .. i can switch it back n forth and everytime i go in manual mode it makes that hiss sound but i can only really hear it if im against a wall

 

Mine has done this from day one as well. Never figured out where it came from and never hurt me any so just left it alone.

 

i actually went to the shop i had it installed at and they said that the aftermarket gaskets actually wear out way faster than the oem ones and they said it's normal so its all good now

 

Does anyone know where I can order all new gaskets for the hks hi power exhaust I just bought? The gaskets look in rough shape so I'm going to get new ones..