August 25th, 2017, 09:18 PM | #1 |
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How do noise-reduction inserts work?
So I was exploring options to quiet my bike down for Laguna Seca. I can't figure out how noise-reduction inserts can possibly work? I have one similar to this for the Yoshimura RS-5 exhaust on my CBR600RR.
And one for an Akra It would appear to me that these would reduce the effective internal volume and baffling surface-area inside the muffler? How does that reduce loudness? Imagine having an even longer solid tube go all the way through to remove ALL off the baffling and this would be maximum loudness, not less? I don't get it. Meanwhile, on the auto front, extreme measures are needed. |
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August 26th, 2017, 08:12 AM | #2 |
Track Clown
Name: Chris
Location: Kingman, AZ
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it changes the air flow, usually involves fiberglass to absorb sound. the silencers also convert wide airflow to a more narrow air flow. I am in the process of building a silencer for my 250 as I run straight pipes and no muffler. I cut my stock exhaust head and got the baffle out, and need to weld some pieces together. Wrap the baffle with fiberglass and then insert it back into the "stock" pipe in order to slip it inside my exhaust.
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August 26th, 2017, 11:54 AM | #3 |
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August 26th, 2017, 02:39 PM | #4 |
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what is the db level at laguna?
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August 26th, 2017, 03:13 PM | #5 |
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I think 92, might be 90 sometimes :/
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August 26th, 2017, 03:20 PM | #6 |
ninjette.org guru
Name: Chris
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What we perceive as noise is actually sound pressure. If you can modify the apparent sound by tuning the harmonics then you get an apparently lesser or greater sound.
Straight through performance exhaust create a distinct sound wave, the baffle changes the tone, by both volume & area reduction this is usually enough to reduce it enough to defeat he dab meter, but not reduce performance to much, they can help in certain parts of the rev range netting you a little more torque. YMMV |
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August 26th, 2017, 03:36 PM | #7 |
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1 out of 1 members found this post helpful. |
August 26th, 2017, 04:25 PM | #8 |
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a little 300/250 with a exhaust sys, will go over the 90 db?
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August 26th, 2017, 05:17 PM | #9 |
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It very well could. Certainly sounds louder than some of big bikes with FACTORY exhausts that were getting black-flagged. Then again, it actually sounds louder to me because the sound isn't aimed backwards any more. My left ear's taken a beating even with ear-plugs. Need to get some of those silicone ones.
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August 26th, 2017, 05:57 PM | #10 |
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sorry to hear this. do you get to test your bike before your session?
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August 26th, 2017, 06:50 PM | #11 |
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I've been going up hill full-throttle past the sound-monitoring station all day and didn't get black-flagged, so I think it's working !!!
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August 26th, 2017, 10:31 PM | #12 |
"a legend in my own mind"
Name: maverick9611
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__________________________________________________
"trying not to get old" |
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August 27th, 2017, 03:06 AM | #13 |
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Glad it worked out!
Did the possibility of getting flagged distract you throughout your run? Lol..cuz I'd go ham on that track at which point they'd need some spike strips to stop me hahahaha |
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August 27th, 2017, 11:59 PM | #14 |
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Track organizer said that would put you on their radar! It's like dragging a 100-lb bag of weed to the airport and asking them to have their dogs sniff it to see if you did a good enough job of sealing bag!!!
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August 28th, 2017, 05:36 AM | #15 |
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August 28th, 2017, 08:00 AM | #16 | |
ninjette.org certified postwhore
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Quote:
Each lap I'd gradually move closer and closer to right side after T5. Eventually I was on racing line on right side closest to sound-booth, no black-flags! Some other Ninja 250R's sound-reduction efforts. |
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August 28th, 2017, 08:03 AM | #17 |
ninjette.org guru
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thats just crazy, as much as i would love to ride that track, i probably wont now.
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August 28th, 2017, 09:41 PM | #18 | |
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Quote:
I think this track is totally worth it! More challenging than Thunderhill. No walls to worry about like Sears/Sonoma. And it has The Corkscrew!!! And due to all the corners, you actually have better chances against the big bikes! |
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August 29th, 2017, 08:18 AM | #19 | |
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Quote:
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