Jeano
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| posted on 29/7/15 at 11:40 AM |
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Exhaust Noise
I have a ZX12 and it pritty loud, im concerned with trackdays tbh.
My end of my exhaust is bolted on so i can fit a wadding to reduce noise. Is the below the best kind of product to use?
Also are they reusable if i remove and then want to refit.
http://furoreproducts.co.uk/exhaust-parts/151-accoustafil-type-exhaust-packing-sheet-500mm-x-400mm.html
Location: Essex
Drives: MK Indy F20c with hairdryer
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adithorp
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| posted on 29/7/15 at 12:53 PM |
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That or acoustafil. It's sewn compressed with a low melting point thread, that once you run the car, melts and allows the mat to expand to fill
the silencer. You would struggle to get it out undamaged and reuse it after. You need to do a search on how much to use as the amount recommended for
accoustafil has been found to be too much by many.
[Edited on 29/7/15 by adithorp]
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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Davey D
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| posted on 29/7/15 at 01:43 PM |
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How big is the exhaust youve got fitted? if you have a small silencer then it will be harder to drop the noise right down
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Jeano
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| posted on 30/7/15 at 08:54 AM |
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Haven't measured the diameter yet
Location: Essex
Drives: MK Indy F20c with hairdryer
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AdamR20
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| posted on 30/7/15 at 09:14 AM |
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Hmm, yes, that is a tiny can.
Have used Acoustafil myself before and it does what it says on the tin (providing you use it sparingly, as has been said), but not sure how effective
it'd be in your case. Worth a try for the money!?
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adithorp
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| posted on 30/7/15 at 09:34 AM |
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That looks like a comined cat'/silencer so the heat effected bit is where the cat' is and the back bit is the silencer. It would appear to
be a 5" dia' with a fairly large bore; maybe 2.5"?
For good silencing you want as long as possible and as large a cross section of silencer (between the perferated tube and outer cat dia' .
Overall yours probably isn't ideal for either 
You might as well try the re-pack (it might have nothing in there) but I suspect you might have to eventually fit a bigger box.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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Slimy38
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| posted on 30/7/15 at 11:02 AM |
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Can you do something with baffles rather than packing? I appreciate that it might kill a few horses at the wheels.
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Jeano
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| posted on 25/2/16 at 11:34 AM |
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I measured my exhaust outlet today at 2.5mm.
Im yet to remove the tip to see whether i have wadding inside to repair but am thinking of ordering the below in addition to the wadding in order to
keep it down.
3" Universal Exhaust Silencer Db Killer Fits Jap Box Baffle Bung
Location: Essex
Drives: MK Indy F20c with hairdryer
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Jeano
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| posted on 1/3/16 at 12:34 PM |
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Tested at 117dB within 0.5m of exhaust at 45 degree etc at 7500rpm
only 99dB from 2m on the other side of the car thou
concerned if i will get it bought down but i have ordered wadding and a bung
Location: Essex
Drives: MK Indy F20c with hairdryer
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Oddified
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| posted on 1/3/16 at 02:40 PM |
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quote:
Originally posted by Jeano
Tested at 117dB within 0.5m of exhaust at 45 degree etc at 7500rpm
That's loud, you'll be very lucky to be able to play on any track with it that loud. I'm surprised that pc plod hasn't shown
an interest too!.
As mentioned above, you'll probably have to change the silencer to a larger outer diameter (longer and/or greater diameter = quieter). Try the
wadding/bung but there probably just isn't enough depth of wadding around the perferated tube and outside case to absorb the noise/pulses
enough.
Ian
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Jeano
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| posted on 3/3/16 at 08:21 AM |
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Ordered some wadding, plan at weekend is to remove the removable baffle and check there is wadding and then repack it or put some in!
Then install the bung i have purchased and review it once more. Ill put new batteries in dB meter to check its accurate.
Location: Essex
Drives: MK Indy F20c with hairdryer
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Phil_1471
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| posted on 3/3/16 at 02:40 PM |
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Where did you get your db meter from? Worried about mine massively now, seems like quiet a few are having issues with noise on track days... Sigh!
You can live in a car but can't rally a house
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The Black Flash
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| posted on 4/3/16 at 01:06 PM |
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quote:
Originally posted by Phil_1471
Where did you get your db meter from? Worried about mine massively now, seems like quiet a few are having issues with noise on track days... Sigh!
The 10 quid jobs from ebay are pretty good IME.
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Jeano
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| posted on 4/3/16 at 02:14 PM |
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Agreed, got mine from Amazon
http://www.amazon.co.uk/Digital-30-130-Monitor-Decibel-Pressure/dp/B00ERQC7Y0/ref=sr_1_1?ie=UTF8&qid=1457100866&sr=8-1&keywords=dB+meter
Location: Essex
Drives: MK Indy F20c with hairdryer
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Phil_1471
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| posted on 4/3/16 at 03:14 PM |
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All these £10ers are adding up lol, how accurate is the iPhone app compared to your meter?
You can live in a car but can't rally a house
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Jeano
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| posted on 4/3/16 at 05:56 PM |
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Everyone says acustafil needs less than recommended. How much less? 1/2? 3/4?
Location: Essex
Drives: MK Indy F20c with hairdryer
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The Black Flash
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| posted on 4/3/16 at 09:00 PM |
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quote:
Originally posted by Phil_1471
All these £10ers are adding up lol, how accurate is the iPhone app compared to your meter?
I don't know for sure, but as I understand it, the microphones in phones do not respond well at the ~100db level - i.e., not very well I
don't think.
But I've not tested.
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907
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| posted on 5/3/16 at 12:12 AM |
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I have two iPhone apps, and a £50 db meter.
All three are within 1 db of each other in the 80 to 120 range.
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Phil_1471
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| posted on 5/3/16 at 07:13 AM |
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Nice to know, will use my iPhone app to get a rough idea :-) save some cash
You can live in a car but can't rally a house
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The Black Flash
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| posted on 6/3/16 at 04:55 PM |
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quote:
Originally posted by 907
I have two iPhone apps, and a £50 db meter.
All three are within 1 db of each other in the 80 to 120 range.
Good to know. I stand corrected 
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Jeano
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| posted on 6/3/16 at 06:08 PM |
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so dismantled my exhaust at the weekend, just to find that there was bairly an filling material to the baffles, just one thin piece around the outside
that kind of floated around the baffles,
i took the entire exhaust off so i can get the hole drilled in for my new bung so will repack the exhaust and see what she measures.
barely any fluff
Location: Essex
Drives: MK Indy F20c with hairdryer
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Davey D
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| posted on 6/3/16 at 08:47 PM |
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That exhaust wadding looks quite dense and compacted? If it is then that won't be helping with the noise
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Jeano
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| posted on 7/3/16 at 06:52 PM |
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Very Dense, very compacted and one thin layer around the entire exhaust around 2mm.
Acoustafil, what does everyone recommend in rtio to there recommendation 80% or shall i just go with it to maximise reduction
Location: Essex
Drives: MK Indy F20c with hairdryer
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Phil_1471
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| posted on 8/3/16 at 08:26 AM |
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Just had my acustafil delivered, be interesting to see how you worked out how much and what the sound is like etc, let us know?!
At idle, my car is 68db's not looking good for a track for me unless I put on an exhaust the size of a cannon.
You can live in a car but can't rally a house
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Davey D
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| posted on 8/3/16 at 10:06 AM |
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With my RaceCo exhaust it is filled with chopped strand loose fibreglass. They are filled to the correct amount by weighing the exhaust with the
wadding inside.
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