Just yesterday I had APS 2.5 inch test pipes put on my car. Before the install I had Borla TD/stock cats/stock headers (with no problems). After the TP install the sound is AWESOME and the gains are very noticeable, however, I have been noticing some strange things. Whenever I accelerate, and even more so when I decelerate (engine brake) I am hearing a psssst'ing sound...sort of like an intake type of noise. I would say its kind of a hiss. I asked around and it seems like this may be symptoms of an exhaust leak. What do ya'll think? (Also, I had non-foulers installed on the TPs and I have thrown a "service engine soon" light...any information on that would be helpful as well) Thanks in advance guys.

 

Normal

 

I noticed the same thing after I installed my Fujitsubo yesterday. I don't hear anything until I get off the throttle, then I hear a very faint and brieft hiss for a moment, like what you hear from an intake. I don't think it's an exhaust leak, but I'm not certain...

 

that is very common with test pipes. i thought the same thing. i never heard a thing with my greddy evo2 catback, then i put on the kinetix resonated test pipes and i get the hiss everytime i let of the gas. i asked around and even heard a few videos, all 350z's with test pipes made this sound when decelerating.

 

Common, goes away w/ larger diameter Y pipe or midpipes. :-D I didnt have it when i had APS TP w/ APS exhaust, and I have it w/ APS TP w/ stock exhaust. When i put on the SVRTech exahust, i don't expect it to be there since its 2.5 TD w/ a 3.5 inch X pipe section.

 

Yeah, I had heard the hiss during decel from others, but mine also sounds like its whooshing during accel as well, this is what worries me. Nobody hears any "intake" ish sound during accel?