I have Berk HFC and Invidia cat-back and I most definitely do have this sound. I wasn't particularly looking for a "solution" as in my experience this may be normal when you change to HFC, with or without a change of your other exhaust components. If anyone who's bothered by it enough to search for a way to eliminate it is successful, I'd be really interested to know how they accomplish it. I doubt thtat it's possible without removing your HFCs though.

 

Oh my bad BB so you do have this sound, looks like it's just the HFCs haha nothing we can do about it lol.

 

Yup, I just drove my car today with my new FI HFC's and Stillen Cat-back. this is on a 07 G35 Sedan, and I heard this hissing sound on deceleration and acclerating in the 1500-2000RPM ranges. Kinda freaked me out thought I had an exhaust leak, went home put my hand near the bottom connection to the y-pipe, and no leak, everything is good and tight! then came on this great forum, and found out it's pretty normal sound! HAHA. so it's all good now, I'll just turn up the radio or keep the windows up with A/C on if it annoys me.

 

Glad the forum could help

 

I have stock exhaust with 350z HR Y Pipe installed and I also get this noise....

Here's my clip in my building's garage

<embed width="448" height="361" type="application/x-shockwave-flash" wmode="transparent" src="http://i313.photobucket.com/player.swf?file=http://vid313.photobucket.com/albums/ll365/tiguy99/Berk%20HFC%20clips/MOV00405.flv">

How did you discover this? Did you ever figure out how to stop it?

I've spent a good amount of time this weekend listening to different exhaust systems out there and noticed that folks with test pipes are also hearing this sound too.

Just take a look at this clip of a 350z with Greddy Evo 2 Exhaust and Resonated Test Pipes

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/IpY3rdK-BD4&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/IpY3rdK-BD4&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>

Its not just us folks with HFCs having this issue. What can it be?

 

Then I'm guessing it's just the way the sound of the engine is and there is no fix apart from going back stock lol.

 

I wouldn't say all that There's gotta be some way to fix it

Wonder if someone with a Vortech can chime in and let us know how a blower would effect the back pressure sound effect.....anybody????

How about some of our turbo and twin turbo friends with HFCs??? Anyone???

 

Well how long have you had your HFcs for I'm hoping that once i break it in it would go away lol!

 

Btw this is what i got from NJ lakeshore from another thread

i know exaclty what the problem is....

2 things.

1 the cross brace under the middle of the car is hitting the exhaust ever so lightly...take it off you wont hear it anymore, then put it back on bc that brace helps the structure of car, but SHIM it down with some washers....

2. the next noise is from the flex pipes rattling so fast....cant get rid of that at all...annoying...


on the first part, it will most likely look like its not rubbing but trust me it is...

 

Okay, I took the cross brace off the car, didn't stop it, so i went under the car while it was up on ramps to check it out, here if what i found out, it's not because of the Y pipe flexing around like crazy, like it said in the other thread, nor is it the flex joints the sound seems to be coming from The y pipe, there the 2 pipes from the cats meet, maybe if we got rid of the Y pipe it would solve the problem?

 

Interesting theories.

When you say flex pipes which ones are you talking about?

I've had my Berk HFCs for about 1 month now give or take an extra week. PErsonally I think its a sound within the manifold pipes themselves that gets exposed when we remove the stock cats and go with Hi Flow Cats or Test Pipes

Keep us posted and awesome work. Someone said the Motordyne XYZ Pipe may solve this issue...

We just need to borrow one each for "research purposes" and we can test out that theory 100%.

Maybe they'd let us keep it too!

 

I have no idea, i might just get rid of the Y and get an H pipe and see if that solves the problem.. hahahaha.

 

At first I thought it was a leak or bolts were not tight enough but it was neither. I found out by watching my videos very carefully i could see the pipe vibrate.


I don't think that has anything to do with that. I've had an X-pipe with my magnaflow exhaust and I had that noise. I've also put the stock exhaust back on (that has a Y-pipe) and still have that noise.

 

^ did you have the resonated X pipe so 11385 or 14385? Because while i was under the car I can hear the sound come from the Y pipe like where the gasses meet, so i'm guessing if we get a resonated one like the mufflers i mentioned it should muffle out the sound? because i know people with the FI exhaust + hfc dont have this problem. At least not when i ask them.

 

This is getting good. Subscribing!