Weird noise coming from my exhaust. Berk HFC and Magnaflow
02-17-2009, 05:08 PM
#76
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.
03-15-2009, 12:48 AM
#78
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. 
03-15-2009, 03:47 PM
#80
Registered Member
I've said what is making the noise plenty of times. Look at post 68 very carefully, you can see the pipe shake making the weird noise. A combination of higher exhaust flow and thinner metal in the aftermarket exhaust and lack of counterweights help aid in the production of the noise. Look at post 45.
As far as i know their is no fix yet. Most people just deal with the noise or most of use don't have the time or money to do trial and error with the exhaust. If you get any ideas post them up.
The video in post 68 is my car with berk HFC's and a "full" catback magnaflow exhaust.
As far as i know their is no fix yet. Most people just deal with the noise or most of use don't have the time or money to do trial and error with the exhaust. If you get any ideas post them up.
The video in post 68 is my car with berk HFC's and a "full" catback magnaflow exhaust.
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">
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?
03-15-2009, 04:14 PM
#82
Registered Member
There's gotta be some way to fix itWonder 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???
03-15-2009, 04:41 PM
#84
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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...
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...
03-15-2009, 05:40 PM
#85
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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?
03-15-2009, 06:13 PM
#86
Registered Member
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...
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...
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!
03-15-2009, 10:00 PM
#88
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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.
03-15-2009, 10:06 PM
#89
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^ 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.