Kassi.k24

2005 350z 35th year anniversary making a hissing sound after reving. So recently I did a clutch replacement, after I had a put everything back together and started driving I noticed a hissing sound coming from under my car after I start accelerating from 0 and decelerating. This only happens at around 2500 rpm. I have headers, test pipe to y pipe and a single exit exhaust. Anyone have a clue what this may be?

would also like to include my other two issues when accelerating from 0 I hear a click sound when I start to role, alone with my transmission shaking a little at around 2500 rpm.

Heel Til I Die

iTrader: (2)

Exhaust leak?

Rear axle click?

Improper installation?

(sigh)

icer5160

iTrader: (4)

The hissing sound might be an exhaust leak or the test pipes if you installed them during the clutch job. I hope you used new, good quality, exhaust flange gaskets between the headers, test pipes, and Y-pipe. Sometimes the flange welds don't like to mate flush, so some high-temp RTV + gasket is required to make a good seal. The clicking sound could be any number of things (rear axle click TSB, brake pads seating/shifting, drive-shaft U-joint failing, loose trans mount, suspension bushings, tie-rod linkages, sway bar bushings, diff bushing, etc...). The trans shouldn't be shaking/vibrating @2500RPM, so I would start looking there. Inspect your trans mount bushing, make sure you torqued down the tunnel brace. Also make sure your driveshaft u-joints are good, if you have excessive play that will cause a noticeable vibration/shake. The same is true for the rear diff, check the bushings. Also make sure you don't have metal on metal contact between the exhaust system and suspension. Never hurts to check the engine mounts as well. These cars are getting old and those rubber mounts are prone to cracking/failing, especially if driven like a d-bag.

Good Luck!
-Icer

Kassi.k24

I’ll start looking into those, I’ve talked to a few people and they all said that a lot of test pipes do that but imma get new gaskets and see if that fixes it. For the other noises I’ll look into everything you listed.

TheRealLoner1

Same here got the same year and model as yours and I got a new exhaust planning on getting another and I hear it everytime when I get it up their and so do my friends but it's like a slight whistle

purpleseo

Is there somebody who fixed this problem? Same here - hiss noise from the exhaust system from 2500 to 3000 rpm. Resonated test pipes were installed.

MicVelo

Over fascination with "test pipes".

From the resident anti-testpipe brigade. 😆

If you lived in the LA basin when the smog was so bad you couldn't see DOWN THE BLOCK, you'd understand why I'm against cat removal. Not to mention confusing the O2 sensors when both upstream and downstream sensors read the same, indicating cat failure. Just imagime what the ECM does.

But whatever, ignore the opinionated ramblings of a crazy old man. 🤡

TheRealLoner1

Idk about you all but all I've done is a full exhaust system to my car and I can still hear a whistling when giving it any amount of gas is their any reason as to why?

MicVelo

If you've replaced the whole system, I'd look in the areas BEFORE the modified pipes. Manifold/header gaskets, cat (or resonated cats/test pipe) junctions. Or possibly, not even exhaust related. Clutch, fan belt, water pump, anything. You need to isolate the origin AREA at least down to rough location then go from there.

icer5160

iTrader: (4)

I had a subtle exhaust sound for years on my Z, I wouldn't call it a "hissing" sound exactly, but more like a puffing/chugging sound with tapping mixed in. It only did it under heavy loads. A few months back when I was installing my Motordyne Catback, I discovered the source of that sound. It was the CAT honeycomb on Bank 1 (Passenger side). The honeycomb wasn't cracked and broken, but it had separated from the inner wall of the tubing, allowing for a small amount of movement. Under heavy load, it was essentially chattering in the exhaust stream. Many years ago, I gobbled up some good, but used CATs, so I simply replaced it and that confirmed the fix.
Cheers!
-Icer

MelissaPeterss

Is there somebody who fixed this problem? Same here