Nissan 370Z Forum - View Single Post

DannyGT · 09-28-2009, 02:27 PM

No...The hiss will come from any test pipe...and to answer one of the posts above me, its not being caused by a particular design flaw, its actually a harmonic resonance (think, frequency) that caused this sound at different rpms. I went threw a long drawn out process and the sound while being caused by test pipes, could almost be felt in the area where most X/Y configs meet. It was very odd, but that resonance was definitly caused by the test pipes.

Usually, between 2-3k while on the gas you can get a hiss/metalic zing/flutter type of sound, very very annoying in my book. Also, on decel during those same rpms, its just a straight hiss...

When I changed from the berk non-res test pipes to the GTM resonated ones it dramatically reduced the sound. In fact, I dont get that rattle on accel anymore, just a slight hiss on decel around 2500rpms.

From what I can tell, it may be possible to kill the sound all together by using those FI pipes that had a HFC & resonator all in one...I also heard that a true-dual exhaust with no connection (h/x/y) doesnt make the sound either. But it also doesnt make good power compared to a nice X setup.

09-28-2009, 02:27 PM	#1859 (permalink)
DannyGT Track Member Join Date: Jan 2009 Location: Jersey Posts: 919 Drives: 370Z (SOLD) Rep Power: 279	No...The hiss will come from any test pipe...and to answer one of the posts above me, its not being caused by a particular design flaw, its actually a harmonic resonance (think, frequency) that caused this sound at different rpms. I went threw a long drawn out process and the sound while being caused by test pipes, could almost be felt in the area where most X/Y configs meet. It was very odd, but that resonance was definitly caused by the test pipes. Usually, between 2-3k while on the gas you can get a hiss/metalic zing/flutter type of sound, very very annoying in my book. Also, on decel during those same rpms, its just a straight hiss... When I changed from the berk non-res test pipes to the GTM resonated ones it dramatically reduced the sound. In fact, I dont get that rattle on accel anymore, just a slight hiss on decel around 2500rpms. From what I can tell, it may be possible to kill the sound all together by using those FI pipes that had a HFC & resonator all in one...I also heard that a true-dual exhaust with no connection (h/x/y) doesnt make the sound either. But it also doesnt make good power compared to a nice X setup. __________________ Performance GTM Stage 1 SC, GTM Res.Test Pipes, Invidia Gemini Exhaust, GTM HD Oil Cooler Wheels & Suspension AME Tracer TM02's 19x9.5F 19x10.5R w/ 265x35F & 305x30R, Hotchkis Sways, BC (BR) Racing Coilovers (Car Sold)