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#1 |
Join Date: Dec 2012
Location: NC
Posts: 1,786
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Jeff was right - THis thing is LOUD!
Outside sounds great. I let a neighbor do a lap around the block after he helped lock down clamps. Sounded great driving off; I couldn't hear it on the back side of the block. Inside is a different story. What I'm not diggin' so much is drone. It's loud between about 1,200 RPM's, to about 1,800, give or take. Gotta' be way below 40 Hz... So I'm thinkin' on a few things here, individually, or in combination, to 'interfere' with the harmonic resonance: 1) Pipe wrap the 2 sections where the resonator was, and the X-pipe. 2) New (or additional) sound material under the carpet interior. I stayed with the original material because it 'smelled' new when I uncovered it for Black conversion. 3) Fitting / welding in a free flowing resonator behind the X-pipe (or 2 individual units, space permitting) Where's Jeff T here; Jeff - did you consider option 3 here? Seems it would be an easy task, if a resonator could be modded for 2 x 3" inlets / outlets... Of course, option 'b' would work too - turn up the radio ![]() What did you do to take the edge off of interior noise, without hampering exhaust flow?
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I'm getting my snappics / threads removed blindly as fast as I can, to get in compliance with copyright / license TOS on the boards here (lots of FSM pages and other copyright / license violations on my part; sorry guys). And thanks to all the guys who didn't whine when I posted those FSM copyrighted / licensed stuff in my threads... ( :thumbsup: [b]and to think I complied with a mod's request to delete a pic of him in a Challenge Car in NCM Museum, so he wouldn't get in hot water)[/b] Thanks to several guys here for sending parts FREE; BearlyFlying, WeGone, Geezer, GoldCylon, and more there, TonyD, mike100, fletchusmc... 1990 #2794; 4L60e Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless, Power Effects 3" [IMG]https://lh5.googleusercontent.com/-GHpfzty7DVU/UQn-0Ru2xAI/AAAAAAAAA14/08mz1p4QLD4/s445/Screenshot-5.png[/IMG] |
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#2 |
![]() Join Date: Feb 2011
Location: San Marcos CA
Posts: 1,802
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Single outlet mufflers will quell the worst of the resonance. The oem resonator was for a slightly higher harmonic and not going to do a lot for the hatchback drone.
I hacked NPP exhaust tips from a C6 and made a control scheme for the vacuum actuation. You'd be surprised at how well it actually works even on louder muffler designs. |
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#3 |
![]() Join Date: Feb 2011
Location: San Marcos CA
Posts: 1,802
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Catalysts help a little too.
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#4 |
Join Date: May 2013
Location: Chicago
Posts: 978
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Get the high temp red RTV out. I had a couple of leaks at the collector area.
I plan on using sound deadening material on my interior. I may also swap the b&b mufflers for the dynomax with the built in noise valve.
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1993 ZR-1 #211 Yellow On Beige Beast #2 1992 ZR-1 #427 Black On Black *Sold* 1985 L98 Blue On Blue *Sold* |
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#5 | |
Join Date: Dec 2012
Location: NC
Posts: 1,786
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![]() Quote:
Karl - 'Get it out'? You mean 'get some hi-temp RTV put IN'? I can see how that might effect harmonics, but all the slip-joints are sealed now...
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I'm getting my snappics / threads removed blindly as fast as I can, to get in compliance with copyright / license TOS on the boards here (lots of FSM pages and other copyright / license violations on my part; sorry guys). And thanks to all the guys who didn't whine when I posted those FSM copyrighted / licensed stuff in my threads... ( :thumbsup: [b]and to think I complied with a mod's request to delete a pic of him in a Challenge Car in NCM Museum, so he wouldn't get in hot water)[/b] Thanks to several guys here for sending parts FREE; BearlyFlying, WeGone, Geezer, GoldCylon, and more there, TonyD, mike100, fletchusmc... 1990 #2794; 4L60e Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless, Power Effects 3" [IMG]https://lh5.googleusercontent.com/-GHpfzty7DVU/UQn-0Ru2xAI/AAAAAAAAA14/08mz1p4QLD4/s445/Screenshot-5.png[/IMG] |
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#6 |
![]() Join Date: Sep 2010
Location: Currituck, NC
Posts: 246
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My first plan was a resonator or resonators in place of the X-pipe.
That is until she said "put the Flowmaster system back on" So I had no choice but to go with her option on her car!! |
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#7 |
Join Date: May 2013
Location: Chicago
Posts: 978
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Yes after putting some miles on the car the slip fit connectors began to leak exhaust. Certainly not loud enough to cause drone and resonance, but it became audible.
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1993 ZR-1 #211 Yellow On Beige Beast #2 1992 ZR-1 #427 Black On Black *Sold* 1985 L98 Blue On Blue *Sold* |
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#8 |
![]() Join Date: Feb 2014
Location: AZ
Posts: 860
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It's loud? Do you have mufflers on it? Is it a daily driver? Mine is wide open, except for the cats, and I can't wait to put headers on it so those "mufflers" are gone too. Still too quiet for me. Oh well, different strokes...
A resonator should help with sound but my understanding is that getting rid of resonance is a VERY difficult thing to do, unless you're installing a "complete" system, such as a Corsa. When we design our own, we can muffle sound but resonance is hit or miss. Best of luck with it, Schrade! |
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#9 | |
![]() ![]() Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,493
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Just a thought.... ![]()
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Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry |
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#10 |
![]() Join Date: Feb 2011
Location: San Marcos CA
Posts: 1,802
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