Here we go again, quiet cat-back clarification needed.
Mar 6, 2011, 10:34 AM
#31
how many extra db's are you willing to deal with?you like quoting db's, but yet you havent stated your target db......"near-stock" is a matter of opinion.
is your ideal exhaust note tolerance/goal "in-cabin" or "general public nuisance" concerns?
Mar 6, 2011, 10:34 AM
#32
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Yes I am centered around a completely 3" setup with absolutely no tapers and preferably running catless.
But just realize, the VT muffler is basically a cutout but its controlled by exhaust gas pressure.
If you have 100.00 and dont mind spending it on something to be the first to test out on, there is something you could try to do.
Buy the Dynomax VT muffler and either drill a couple holes on the plate inside to help relieve some of the pressure pulses from kicking it open or cut it and experiment with different spring tensions.
And no, running 2 bullet muffler with a cat will not be very quiet. The bullet muffler is a great lightweight muffler but not a great quieting muffler.
But just realize, the VT muffler is basically a cutout but its controlled by exhaust gas pressure.
If you have 100.00 and dont mind spending it on something to be the first to test out on, there is something you could try to do.
Buy the Dynomax VT muffler and either drill a couple holes on the plate inside to help relieve some of the pressure pulses from kicking it open or cut it and experiment with different spring tensions.
And no, running 2 bullet muffler with a cat will not be very quiet. The bullet muffler is a great lightweight muffler but not a great quieting muffler.
Yeah, I don't mind blowing $100, but there are many problems with this. One, it will kill the resale of my Perrin catback to someone who wants a louder-than-***** exhaust. Two, I don't want it to be as loud as it is now at WOT. If I'm not mistaken, all these valved mufflers do is quiet them down at less than WOT. When I am out of traffic, I hit the gas. I'm tired of sounding like I am going 100 when I'm just blasting to 50. Everyone that is within sight range stops what they are doing, turns, and looks directly at my car, often with a look of
As someone (maybe even you) said in another thread, it's embarrassing to drive something that loud, for me. It is completely unbearable to me on the highway. Granted, this was brought to life during a 7hr road trip, but the point stands. The next time that car leaves the garage will be for exhaust work, haha.
Mar 6, 2011, 10:50 AM
#33
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To be clear, I'm not shooting for Prius-quiet. I am shooting for wife-approved, and also future manned child-seat-approved. I'm not out to impress, unless someone is impressed by quiet exhausts.
Mar 6, 2011, 11:10 AM
#34
Some comments about dB readings. Please keep in mind that a reading in itself, ie. the number, is meaningless without an attached weighting. The majority of exhaust measurements are done A-weighted, and the results are displayed as dBA. An A-weighting is supped to represent a response most sensitive to the human ear, based on Fletcher-Munson curves that drive the logarithmic function responsible for the calculation. What does this mean to us? It means that low-frequency exhaust noise (the kind that most of us deal with) is omitted from the reading. Now, if we were to discuss C-weighted readings, all the talk about dBs could have a defined relevance.
Mar 6, 2011, 11:15 AM
#35
Well my current setup consists of this:
O2 housing > Down Pipe > 6" Center muffler > DynoMax VT muffler
At WOT it is not obnoxiously loud like a cutout and it is not Stock quiet either. It does have the center muffler lowering the db and as well as the Dynomax vt at the rear has a portion inside that does some muffling as well. Problem is I never heard it from the outside 3rd person point of view, only in cabin with windows up and down.
I cant make any video clips right now because I currently switched to a new o2 housing and I have a huge leak on the hotside to o2 connection. The bolt cross threaded and broke so at one corner there is no bolt holding it donw and has a leak. Its my daily driver so I cant afford any down time thats why I installed it this way until maybe this wednesday I'll take if off to drill out that bolt and fix the issue.
Here are some clips I took of the muffler a while back. Maybe you saw it in the VT thread post 2. But I was running a HFC and not the center 6" muffler in the video. I switched catbacks thats why i had the HFC later I switched to the center muffler and it is a little quieter during WOT compared to the cat.
http://www.youtube.com/watch?v=sZ4DTKTtff0
WOT with driver side window open
http://www.youtube.com/watch?v=76KESzFTSnE
WOT with windows closed
http://www.youtube.com/watch?v=bXb-uvwSBbg
O2 housing > Down Pipe > 6" Center muffler > DynoMax VT muffler
At WOT it is not obnoxiously loud like a cutout and it is not Stock quiet either. It does have the center muffler lowering the db and as well as the Dynomax vt at the rear has a portion inside that does some muffling as well. Problem is I never heard it from the outside 3rd person point of view, only in cabin with windows up and down.
I cant make any video clips right now because I currently switched to a new o2 housing and I have a huge leak on the hotside to o2 connection. The bolt cross threaded and broke so at one corner there is no bolt holding it donw and has a leak. Its my daily driver so I cant afford any down time thats why I installed it this way until maybe this wednesday I'll take if off to drill out that bolt and fix the issue.
Here are some clips I took of the muffler a while back. Maybe you saw it in the VT thread post 2. But I was running a HFC and not the center 6" muffler in the video. I switched catbacks thats why i had the HFC later I switched to the center muffler and it is a little quieter during WOT compared to the cat.
http://www.youtube.com/watch?v=sZ4DTKTtff0
WOT with driver side window open
http://www.youtube.com/watch?v=76KESzFTSnE
WOT with windows closed
http://www.youtube.com/watch?v=bXb-uvwSBbg
Mar 6, 2011, 11:30 AM
#36
I don't remember what mode the db measuring device was in when I measured my exhaust.
That is why I compared it to the stocker.
I can say that by running silencers under the car was quieter in-cabin than my first exhaust with the silncer near the back/ before the muffler.
I struggled to locate the largest casing that featured a 3" in/out. I opted for a round unit to have the largest section of muffling between the trunk.
That is why I compared it to the stocker.
I can say that by running silencers under the car was quieter in-cabin than my first exhaust with the silncer near the back/ before the muffler.
I struggled to locate the largest casing that featured a 3" in/out. I opted for a round unit to have the largest section of muffling between the trunk.
Mar 6, 2011, 11:40 AM
#38
Lieesssss!
See:
Found at project-buschur-double-magnaflow-quiet-exhaust thread.
However, if you have a video clip I'm willing to watch it. I originallythought I would go with the RRE Stealth until I started reading these "quiet exhaust project" threads.
Got a video/sound clip?
See:
Found at project-buschur-double-magnaflow-quiet-exhaust thread.
However, if you have a video clip I'm willing to watch it. I originallythought I would go with the RRE Stealth until I started reading these "quiet exhaust project" threads.
Got a video/sound clip?
http://www.youtube.com/watch?v=S3cBueDkbMo
Here's my custom exhaust for comparison.
http://www.youtube.com/watch?v=XWflJ5X4_2s
Last edited by 4G63kevin; Mar 6, 2011 at 11:42 AM.
Mar 6, 2011, 01:18 PM
#39
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hmm... I'm now completely unconvinced of the quality of various Youtube videos.
For reference, here is mine:
http://www.youtube.com/watch?v=7qAZiCgLlKg
Your custom system sounds like mine, but you'd have to max the volume on your 5.1. My video (taken with a phone) you'd have to max it then multiply it times 10, seriously. Now I'm even more doubtful with what I'm seeing online, which echoes what others have said.
FJF: more than I want to know,
but noted, and helpful.
BluEVOIX: I'd be satisfied with that WOT.
I'd have to say that overall I am hating life. My car does not sound loud in that clip above, but let me tell you, just from that thing idling, my cat will sleep with one eye open for a week. In the time it took my car to settle down into idle, THREE neighbors walked out of their houses, into the street, and peeked into my garage to see what the **** I was doing. I may has well have fired a gun in my garage, this is no exaggeration.
For reference, here is mine:
http://www.youtube.com/watch?v=7qAZiCgLlKg
Your custom system sounds like mine, but you'd have to max the volume on your 5.1. My video (taken with a phone) you'd have to max it then multiply it times 10, seriously. Now I'm even more doubtful with what I'm seeing online, which echoes what others have said.
FJF: more than I want to know,
but noted, and helpful.BluEVOIX: I'd be satisfied with that WOT.
I'd have to say that overall I am hating life. My car does not sound loud in that clip above, but let me tell you, just from that thing idling, my cat will sleep with one eye open for a week. In the time it took my car to settle down into idle, THREE neighbors walked out of their houses, into the street, and peeked into my garage to see what the **** I was doing. I may has well have fired a gun in my garage, this is no exaggeration.
Last edited by FERNO; Mar 6, 2011 at 01:43 PM.
Mar 6, 2011, 01:25 PM
#40
I tried to be brief, knowing that folks usually prefer a quick answer to a complex question. It's not easy to condense something like this into a snippet of text that can be understood by everyone reading the thread. The substance of the matter is this: dBA readings tell you very little about an exhaust's true volume, as the reading, itself, is dependent of frequencies that don't fully impact one's perception of exhaust noise.
Last edited by FJF; Mar 6, 2011 at 01:28 PM.
Mar 6, 2011, 02:34 PM
#43
So do you want this?
just a tip for those wanting quiet. the magnaflow offset in/ offset out is very quiet muffler. center in /center out not near as quiet. I am a big fan of quiet myself. I am pretty sure it gets even more quiet with age.
I am currently making exhaust for my evo1. I was able to squeeze an evo 8 meagan rear muffler where cat used to live. I think I am going to try offset/offset borla in the rear.
here is pic of why fujitsubo are so quiet. they really neck down on inside of straight through muffler. the e-bay meagan resonator does same thing.
I am currently making exhaust for my evo1. I was able to squeeze an evo 8 meagan rear muffler where cat used to live. I think I am going to try offset/offset borla in the rear.
here is pic of why fujitsubo are so quiet. they really neck down on inside of straight through muffler. the e-bay meagan resonator does same thing.
Mar 6, 2011, 02:50 PM
#44
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I want the info, yes. Not necessarily the step down, but I'm not sure which fujitsubo he is running.
TBH, at this point, I am willing to consider non-straight through or step-down designs that will allow 40hp over stock.
If I can put it on and still make ~400whp and it is QUIET? I'll consider it. I would seriously consider the Dynomax VT if it weren't for the rattle, and if I had a cheap cat-back to mount it to.
What do you think about the el-cheapo megan cat-back ebay special with the Dynomax VT welded in? Maybe cut out the megan silencer and put it into the pipe towards the front with the VT behind it? Then I'd have HFC > megan muffler > dynomax vt. Of course, I have no idea if the megan is 3" internal, so at that point I may be better off with the medallion or trying to find a Greddy SP2...
I really didn't expect this kind of uphill battle. I've seen 9-second GNX's that were whisper quiet, the only thing you hear is the turbo.
TBH, at this point, I am willing to consider non-straight through or step-down designs that will allow 40hp over stock.
If I can put it on and still make ~400whp and it is QUIET? I'll consider it. I would seriously consider the Dynomax VT if it weren't for the rattle, and if I had a cheap cat-back to mount it to.
What do you think about the el-cheapo megan cat-back ebay special with the Dynomax VT welded in? Maybe cut out the megan silencer and put it into the pipe towards the front with the VT behind it? Then I'd have HFC > megan muffler > dynomax vt. Of course, I have no idea if the megan is 3" internal, so at that point I may be better off with the medallion or trying to find a Greddy SP2...
I really didn't expect this kind of uphill battle. I've seen 9-second GNX's that were whisper quiet, the only thing you hear is the turbo.
Mar 6, 2011, 03:09 PM
#45
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Also, I am willing to buy the quietest cat-back available at my price-point and if it is not quiet enough, start 'parting out the loudness' starting with the turbo and the cams.
I have no problems going to 264's (or stock cams) with an FP green or IX turbo. I can still make 350whp+. I don't really want to, but considering the extra cash I will receive when downgrading and selling my stuff, that may be the best option anyway.
So considering that... what is the quietest, no-rattle option for ~$500? The Greddy SP2? Bushur magnaflow cat-back? Any other stealth?
I have no problems going to 264's (or stock cams) with an FP green or IX turbo. I can still make 350whp+. I don't really want to, but considering the extra cash I will receive when downgrading and selling my stuff, that may be the best option anyway.
So considering that... what is the quietest, no-rattle option for ~$500? The Greddy SP2? Bushur magnaflow cat-back? Any other stealth?