ttalps2000
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| posted on 14/12/17 at 08:38 AM |
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Re-Packable Silencer
Measured my noise last night and it is coming out at 100Db (calibrated meter)
I am running a Fisher Fury silencer. All I need to do is get through the IVA re-test. It was hit and miss last time and they accepted it, but now
having a new engine will want to do it again I expect.
So, do I put in a DB killer, or re-pack the silencer? Never had the silencer apart, so I'm not sure how much wadding is in there!
If re-packing is the best way to go, whats the best stuff to use please?
Thanks
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Myke 2463
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| posted on 14/12/17 at 09:19 AM |
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Acousta-Fil Exhaust Silencer Packing
Be Lucky Mike.
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melly-g
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| posted on 14/12/17 at 10:22 AM |
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I agree with the above Acoustafil.
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ttalps2000
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| posted on 14/12/17 at 10:29 AM |
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Where is the best place to get it from?
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ttalps2000
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| posted on 14/12/17 at 10:43 AM |
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Just been reading up on the acoustafil packing and it looks like you need to get the exhaust nice and hot and through a few cycles to get it to expand
correctly etc!
Think a DB killer is in order and I only need to drop 1db!
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WallerZero
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| posted on 14/12/17 at 11:05 AM |
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For the sake of the IVA, DB killer, it can fall out on the way home 
However, going back a step, are you IVA'ing again doing an engine swap? Is everything else the same? If so, write to the DVLA, notify them of
the engine swap and you don't need an IVA test again. And it costs nothing to write to them!
http://zachsgbszero.blogspot.co.uk/
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ttalps2000
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| posted on 14/12/17 at 11:20 AM |
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having to do an engine swap to get through IVA re-test! As long as it stays in there for the noise test it will be gone after!!
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Mr Whippy
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| posted on 14/12/17 at 12:45 PM |
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seems a bit drastic to get through the IVA, change engines....what engine were you using before that was so noisy it couldn't be quietened
down?!
[Edited on 14/12/17 by Mr Whippy]
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ttalps2000
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| posted on 14/12/17 at 12:53 PM |
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was all due to paper work with engine age and cat, but they will want to re-test the noise due to an engine change on the re-test!
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ttalps2000
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| posted on 14/12/17 at 01:08 PM |
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looking at the db killers, I'm not sure I will actually get one in my exhaust! The tail pipe is at a 90 degree bend and very short! Could put it
in the straight section as it comes out of the silencer, but then I would not be able to do the bolt up on it! grrrr!
Any other recommendations on wadding that works well, but does not need to go through heat cycles?
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pewe
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| posted on 14/12/17 at 03:34 PM |
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These guys Acoustifil
Also CBS supply same/similar wadding.
HTH.
Cheers, Pewe10 
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ttalps2000
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| posted on 14/12/17 at 09:43 PM |
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all ordered! Thanks for the help!
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birdii
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| posted on 14/12/17 at 11:16 PM |
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I fitted my db killer at the manifold to silencer joint. Due to the pipe inside diameters I had to cut some material off the dB killer then fettle it
using a grinder until it was a good fit up the pipe then held it in place with a few tack welds.
Reduced my noise from 105 to around 96 when I tested with a calibrated meter. Was 98 at Iva but the tester had me rev at well over 75%.
My experience with repacking on a previous exhaust changed the sound very little.
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907
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| posted on 15/12/17 at 07:01 AM |
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Packing with Acousta-fil
The internet is a wonderful thing but unfortunately along with the snippets of quality information there's also a load of crap.
It's up to the reader to sort the wheat from the chaff.
I did a quick random search on this subject and found several outlets that will sell you half the amount needed in their effort
to be competitive (or make more profit).
This for instance is a typical misleading photo. (Count the loops, its not rocket science)
 
Random misleading internet pic
This one, another random stolen internet pic, is nearer the mark.
 
correctly packed. random pic
Acoustic-fil does come in various widths and temperature grades, another thing the eBay sellers fail to mention, and does
require a good 30 mile thrash to melt the stitching and allow it to "fluff".
This will however depend on the fuel/air mix and ignition advance settings of the car in question.
My own (new) exhaust passed IVA (just) but 1000 miles later and it ran at 10 dBa lower.
It's now 2.5 years later and have taken it apart a couple of times just to see how its going but have never needed to re-pack.
I once was asked to re-pack a 600 hp Nobel that had done 10k since I made the system and although I did as asked it didn't
need it. I kept the stuff I took out to show him and he was well pleased. I now use it to show other customers what to expect,
providing the car is set up right.
Hope these ramblings help.
Paul G
[Edited on 15/12/17 by 907]
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ttalps2000
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| posted on 15/12/17 at 08:44 AM |
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Thanks for your input.
I found a handy calculator for the wadding and it suggests I needed 1.28m and I need a 500mm width.
So I have ordered 2m in a 500mm width from Demon Tweeks, so I should have plenty to do what I need
Getting it hot enough is a bit of a concern as I am unable to drive it at present, so can only let it fast idle etc.
Maywell get a DB killer too and see if I can squeeze it in somehow just to be safe. I only need to drop 1db!
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ttalps2000
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| posted on 15/12/17 at 09:08 AM |
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ordered a DB killer now to be safe!
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40inches
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| posted on 15/12/17 at 09:11 AM |
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quote:
Originally posted by ttalps2000
Thanks for your input.
I found a handy calculator for the wadding and it suggests I needed 1.28m and I need a 500mm width.
So I have ordered 2m in a 500mm width from Demon Tweeks, so I should have plenty to do what I need
Getting it hot enough is a bit of a concern as I am unable to drive it at present, so can only let it fast idle etc.
Maywell get a DB killer too and see if I can squeeze it in somehow just to be safe. I only need to drop 1db!
Using the online calculator, I couldn't get all the filling in the can, used about 2/3rds. If I remember correctly, the filling should be
slightly loose to allow for expansion.
Also if you check your fail certificate, you are (were?)allowed to drive the car, insured, to a place for remedial work with reference to the failure
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907
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| posted on 15/12/17 at 09:24 AM |
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quote:
Originally posted by ttalps2000
Thanks for your input.
I found a handy calculator for the wadding and it suggests I needed 1.28m and I need a 500mm width.
So I have ordered 2m in a 500mm width from Demon Tweeks, so I should have plenty to do what I need
Getting it hot enough is a bit of a concern as I am unable to drive it at present, so can only let it fast idle etc.
Maywell get a DB killer too and see if I can squeeze it in somehow just to be safe. I only need to drop 1db!
Mmm, 500 is a short can. 2m is plenty. Should have 300mm over assuming 2" id x 6" od
Note in the pic they have used 5 layers. ( ish )
You say this is for an IVA re-test, and that you can't drive it, so again I assume your using a trailer.
More assumption: You can't run at home as that would upset the neighbours so load the car on your trailer,
take it to a quiet stretch of road and run it on the trailer, or on the way to IVA.
Paul G
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ttalps2000
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| posted on 15/12/17 at 09:30 AM |
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Insurance companies wont insure you now if the car fails and going back for a re-test! Seems to have all changed a bit again!
Yes using a trailer to take it every where at the moment!
The neighbours are used to hearing the car regular in the evenings now!
I think the easiest thing for IVA is going to be the DB killer tbh! Got both options on the way so will see what I can do with it.
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