Unbelievable rasp with RESONATED tp's and stock exhaust, help PLEASE
08-07-2007, 06:37 PM
#21
Registered User
Join Date: Mar 2006
Location: SF
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
Hey guys, I helped put benny's test pipes in. that was a fun and frustrating day. We rounded a nut pretty bad and that caused a lot of pain..
but anyways..
I think benny and i are disagreeing on "rasp" and the sound we're hearing. A few question, if you hear rasp, would you hear it from the exhaust exit? The muffler section where exhaust actually comes out...if it's rasp would you hear it there or somewhere else along the piping? We hear it right under the passenger seat so that made me think it's not rasp. Also, is the rasp sound generated along with the regular exhaust note/sound? I hear the noise separate from the exhaust sounds to the sound we're hearing. What I hear is very much like metal to metal contact.
Well, when benny gets off his lazy butt and make a vid, we'll find out.
Follow up, when I was putting on the test pipe, the clearance was very close if not actually touching the metal shield under the car. The sound that it's making is from the test pipe I did, but I did tell benny that it's really close/touching so don't blame me man! Anyways, I remember when putting them on that if I wanted to align the three bolts from the headers or whatever that comes before the test pipes..to the test pipes, that it would HAVE to touch the metal shield and the body. I'm thinking how we can fix this problem. We will probably have to unbolt the whole system and align and rebolt huh? That is kind of a pain..arg.
anyways, thanks for the help!
and yes benny i am that bored.
but anyways..
I think benny and i are disagreeing on "rasp" and the sound we're hearing. A few question, if you hear rasp, would you hear it from the exhaust exit? The muffler section where exhaust actually comes out...if it's rasp would you hear it there or somewhere else along the piping? We hear it right under the passenger seat so that made me think it's not rasp. Also, is the rasp sound generated along with the regular exhaust note/sound? I hear the noise separate from the exhaust sounds to the sound we're hearing. What I hear is very much like metal to metal contact.
Well, when benny gets off his lazy butt and make a vid, we'll find out.
Follow up, when I was putting on the test pipe, the clearance was very close if not actually touching the metal shield under the car. The sound that it's making is from the test pipe I did, but I did tell benny that it's really close/touching so don't blame me man! Anyways, I remember when putting them on that if I wanted to align the three bolts from the headers or whatever that comes before the test pipes..to the test pipes, that it would HAVE to touch the metal shield and the body. I'm thinking how we can fix this problem. We will probably have to unbolt the whole system and align and rebolt huh? That is kind of a pain..arg.
anyways, thanks for the help!
and yes benny i am that bored.
08-07-2007, 06:49 PM
#22
Registered User
Join Date: Feb 2006
Location: SoCal
Posts: 747
Likes: 0
Received 0 Likes
on
0 Posts
Well..thanks for chiming in...
You have an exhaust leak - whether you cracked the the testpipes, didn't get the gasket to seal, or messed something else up...you have a leak.
The only place you should ever hear exhaust note/tones/sound etc...is from tailpipes.
If the sound changes as the RPM go up and down, as it gets hotter from a cold start, etc...its an exhaust leak.
If you hear banging against the car - you'd probably feel it a bit in the floor as well....and likely notice the rubbing/hit areas under the car.
NOW with that said - it IS POSSIBLE that you are just rubbing slightly on a heat shield. Bend it back with a screw driver/breaker bar/etc...and see what happens.
I'm betting my farm on the exhaust leak...for he loose bolt, that wasn't torqued right.
EDIT: if you look at the exhaust connections - and notice black soot around them, coming out of one side, etc...it's an exhaust leak..and that is where it is.
Rick
You have an exhaust leak - whether you cracked the the testpipes, didn't get the gasket to seal, or messed something else up...you have a leak.
The only place you should ever hear exhaust note/tones/sound etc...is from tailpipes.
If the sound changes as the RPM go up and down, as it gets hotter from a cold start, etc...its an exhaust leak.
If you hear banging against the car - you'd probably feel it a bit in the floor as well....and likely notice the rubbing/hit areas under the car.
NOW with that said - it IS POSSIBLE that you are just rubbing slightly on a heat shield. Bend it back with a screw driver/breaker bar/etc...and see what happens.
I'm betting my farm on the exhaust leak...for he loose bolt, that wasn't torqued right.
EDIT: if you look at the exhaust connections - and notice black soot around them, coming out of one side, etc...it's an exhaust leak..and that is where it is.
Rick
Last edited by ISMSOLUTIONS; 08-07-2007 at 06:51 PM.
08-07-2007, 11:07 PM
#23
New Member
Thread Starter
iTrader: (5)
Join Date: Mar 2006
Location: San Francisco
Posts: 705
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by ISMSOLUTIONS
OK -
So I've NEVER said rasp is when you hear the pops and stuff from your exhaust...
Put your lips together and force air through them...when your lips flap around, like a fan beating a raw piece of meat - that slapping sound - is real similar to rasp...only rasp is worse, louder and can cause grown men to cry!
Rasp is indicative of a non-balanced exhaust system. It CAN also be characteristic of an engine's firing order - if it cannot keep up with the pulse expulsion. When the exhaust cools too much during it's travels, the pulse backs up against the colder air. So as it 'gasps' you get that 'rasp' sound.
Now - you can have a wide open exhaust - and not enough exhaust pressure to keep the air hot enough to keep flowing through the pipe - you can get rasp and extreme drone from this. EVEN WITH MUFFLERS!
The with 'mufflers' scenario is when a system has been designed to work a specific way - say, a catback system. If it has not been designed to work with headers or testpipes or HFC's - then you're gambling on the result when you change it's specifically designed dynamic of flow characteristics.
So - you can speed-up the pulse - but if it backs up because of other deficiencies - you'll have back pressure, rasp, drone, loss of performance - among possibly other things.
So it's really important to know what the capabilities of an exhaust system are before you buy it - because if you decide to augment that environment, you may not have a completely compatible system - and you wont be happy in the end.
Testpipes are known for causing rasp to appear - as most system are not designed to allow that level of flow. Some do work however, like HKS, Stillen and Fast Intentions - and depending on the parts chosen, they can rasp as well. Some people like a certain degree of rasp - and technically, all exhaust sound is a form of rasp. If there is not a bottleneck, filtering or rasp - just run your car on open headers to see what ZERO rasp sounds like - you'll be more than happy with your rasp
So - in re-reading this thread - there are also some possibilities that the OP doesn't really know what rasp is or sounds like...in his case - this could be pipes rattling the undercarriage...
We need a sound clip...if you can't hear it outside...it's likely not rasp - could be an exhaust leak??? Where is the sound coming from? Tailpipes? Under car?
Rick
So I've NEVER said rasp is when you hear the pops and stuff from your exhaust...
Put your lips together and force air through them...when your lips flap around, like a fan beating a raw piece of meat - that slapping sound - is real similar to rasp...only rasp is worse, louder and can cause grown men to cry!
Rasp is indicative of a non-balanced exhaust system. It CAN also be characteristic of an engine's firing order - if it cannot keep up with the pulse expulsion. When the exhaust cools too much during it's travels, the pulse backs up against the colder air. So as it 'gasps' you get that 'rasp' sound.
Now - you can have a wide open exhaust - and not enough exhaust pressure to keep the air hot enough to keep flowing through the pipe - you can get rasp and extreme drone from this. EVEN WITH MUFFLERS!
The with 'mufflers' scenario is when a system has been designed to work a specific way - say, a catback system. If it has not been designed to work with headers or testpipes or HFC's - then you're gambling on the result when you change it's specifically designed dynamic of flow characteristics.
So - you can speed-up the pulse - but if it backs up because of other deficiencies - you'll have back pressure, rasp, drone, loss of performance - among possibly other things.
So it's really important to know what the capabilities of an exhaust system are before you buy it - because if you decide to augment that environment, you may not have a completely compatible system - and you wont be happy in the end.
Testpipes are known for causing rasp to appear - as most system are not designed to allow that level of flow. Some do work however, like HKS, Stillen and Fast Intentions - and depending on the parts chosen, they can rasp as well. Some people like a certain degree of rasp - and technically, all exhaust sound is a form of rasp. If there is not a bottleneck, filtering or rasp - just run your car on open headers to see what ZERO rasp sounds like - you'll be more than happy with your rasp
So - in re-reading this thread - there are also some possibilities that the OP doesn't really know what rasp is or sounds like...in his case - this could be pipes rattling the undercarriage...
We need a sound clip...if you can't hear it outside...it's likely not rasp - could be an exhaust leak??? Where is the sound coming from? Tailpipes? Under car?
Rick
So i'm trying to understand what your saying about rasp. The exhaust flow coming out my headers and through the TP's is becoming restricted when it hits the smaller diameter y-pipe and then what? It shouldn't be escaping from the flange... Anyways, thanks again you guys. Hope the vids will shed some insight.
http://www.youtube.com/watch?v=1NGagAvqHk8
http://www.youtube.com/watch?v=6Fyc8oEUz7I
http://www.youtube.com/watch?v=s6y-7iSVBh8
Last edited by chishifu; 08-07-2007 at 11:13 PM.
08-08-2007, 07:10 AM
#27
Registered User
Join Date: Feb 2006
Location: SoCal
Posts: 747
Likes: 0
Received 0 Likes
on
0 Posts
OK - thanks for the video!!!
You don't have RASP - sound like your Y-pipe is the issue, or the headers are leaking, or a weld is cracked/broken somewhere.
Rasp will not leak from flange - if it did, it would be a leak. All sound SHOULD come from your tailpipes.
That whhooosshhhh of air is what I am assuming your issue is....and it could very well be the flex joints on the y-pipe, if it has them. Could also be a bad CAT - maybe it had a broken brick to begin with.
Without seeing the car in person, on a lift...that's about all I can tell you.
Rick
You don't have RASP - sound like your Y-pipe is the issue, or the headers are leaking, or a weld is cracked/broken somewhere.
Rasp will not leak from flange - if it did, it would be a leak. All sound SHOULD come from your tailpipes.
That whhooosshhhh of air is what I am assuming your issue is....and it could very well be the flex joints on the y-pipe, if it has them. Could also be a bad CAT - maybe it had a broken brick to begin with.
Without seeing the car in person, on a lift...that's about all I can tell you.
Rick
08-08-2007, 08:06 AM
#29
Registered User
iTrader: (4)
Join Date: Sep 2005
Location: St. Louis
Posts: 554
Likes: 0
Received 0 Likes
on
0 Posts
I believe I'm having this same problem. Nissan said when I let off the throttle, my pipes are shaking pretty bad at the flex section in the Y-pipe. Do you think some exhaust wrap would silence this? Hell, I'll even put dynamat over the exhaust wrap if you guys think it will help.
08-08-2007, 08:15 AM
#30
Registered User
Join Date: Feb 2006
Location: SoCal
Posts: 747
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Mr_Drifter
I believe I'm having this same problem. Nissan said when I let off the throttle, my pipes are shaking pretty bad at the flex section in the Y-pipe. Do you think some exhaust wrap would silence this? Hell, I'll even put dynamat over the exhaust wrap if you guys think it will help.
Flex joints that are flexing - is a good thing - however you could have bad flex joints that need to be replaced as well..
Oh...no dynamat by the way...unless you want the horrible smell of burning rubber, a fire, etc...for the rest of the time you own your car - or until you replace the section
08-08-2007, 09:34 AM
#31
Registered User
iTrader: (1)
Join Date: Jun 2005
Location: K.G. VA
Posts: 222
Likes: 0
Received 0 Likes
on
0 Posts
I have a hissing sound that is pretty constant under acceleration. Not sure if its as bad as yours but I'm pretty positive its not from the headers or test pipes since I double checked both. The only thing I can think of is the flex pipes. Definitely not rasp though.
08-08-2007, 04:18 PM
#32
Registered User
Join Date: Mar 2006
Location: SF
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
The problem isn't really a woosh of air, I don't know if the video really shows it but it's a high pitch rattle...doesn't sound like air at all. more like metal to metal.
08-08-2007, 05:12 PM
#33
Registered User
Join Date: Feb 2006
Location: SoCal
Posts: 747
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by SubaruSTiMike
The problem isn't really a woosh of air, I don't know if the video really shows it but it's a high pitch rattle...doesn't sound like air at all. more like metal to metal.
08-08-2007, 06:49 PM
#35
Registered User
Join Date: Aug 2007
Location: Germany
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
similar problem, please help
Hi, I have a similar problem.
I have the G200 with no other modifications and without silencers. I have a loud rasp sound from 3000 r.p.m. up to the end and that in every gear. I live here in Germany and haven't found a solution yet. Any ideas guys?
I have the G200 with no other modifications and without silencers. I have a loud rasp sound from 3000 r.p.m. up to the end and that in every gear. I live here in Germany and haven't found a solution yet. Any ideas guys?
Last edited by Freakzilla; 08-09-2007 at 02:40 PM.
08-08-2007, 06:49 PM
#36
New Member
Thread Starter
iTrader: (5)
Join Date: Mar 2006
Location: San Francisco
Posts: 705
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by soleil350z
i had test pipe on stock exhaust and made the same noise...its def the y pipe heat shield thats making that noise...i now have the turboxs exhaust and the noise is completly gone....def get an aftermarket y pipe and that should take care of the noise
08-08-2007, 07:11 PM
#38
Registered User
Join Date: Feb 2006
Location: SoCal
Posts: 747
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by chishifu
I think you're spot on with the analysis. I just remembered today that I took off two of the bolts that hold the y-pipe heat shield on to get access to the bolts on the flange, and never put them back on. Thus, would the heat shield be rattling around? Does this sound feasible to anyone? Thanks in advance.
08-08-2007, 07:13 PM
#39
Registered User
Join Date: Feb 2006
Location: SoCal
Posts: 747
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Freakzilla
Hi, I have a similar problem.
I have the G200 with no other modifications and without silencers. I have a loud rasp sound from 3000 r.p.m. up to the end and that in every gear. I live here in Germany and haven't found a solution yet. Any ideas guys? By the way, it only happens when I accelerate quickly.
I have the G200 with no other modifications and without silencers. I have a loud rasp sound from 3000 r.p.m. up to the end and that in every gear. I live here in Germany and haven't found a solution yet. Any ideas guys? By the way, it only happens when I accelerate quickly.
If it's all tailpipe - then welcome to the sound of the Invidia system...really..everyone I have heard has rasp.
If it's like this thread, otherwise...just read the threads last ~10 posts...
Rick
08-08-2007, 08:37 PM
#40
Registered User
Join Date: Mar 2006
Location: SF
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by chishifu
I think you're spot on with the analysis. I just remembered today that I took off two of the bolts that hold the y-pipe heat shield on to get access to the bolts on the flange, and never put them back on. Thus, would the heat shield be rattling around? Does this sound feasible to anyone? Thanks in advance.
Bet you 5 bucks thats the problem. lets put those bolts back on this weekend.
Thread
Thread Starter
Forum
Replies
Last Post
