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How to repack silencer?
corrado vr6 - 3/9/13 at 10:36 PM

Hi there,

When people talk about repacking their silencer, how do you do it and what do you use, some mention wire wool loosely stuffed up there and others say not to use wire wool?

When saying stuff it up in the silencer is it actually a case of stuffing a piece up the exhaust and pushing it further in using a flexible rod??

I ask because I need to lower the db of Mk Indy R1

Sorry if this is a stupid question, but I really don't know

Cheers Greg

Wheels244 - 3/9/13 at 11:22 PM

Greg

It normally means taking the silencer apart, drilling rivets out etc and replacing the noise absorbent material with new.
Wire wool would degrade very quickly - I'd use the proper material. Have a look on ebay or one of the kit car part suppliers websites.

HTHs

Rob

Wheels244 - 3/9/13 at 11:25 PM

Here you go

Acoustafil Exhaust Silencer Muffler *EASYFIT* Packing Wadding - a "'proper job"'

dhutch - 4/9/13 at 04:45 AM

Yes, in short:

Repacking it is opening it up, either by drilling our rivets if its designed for it, or slitting it open and welding it back together if its not, and filling it full of suitable material, bearing in mind that while not enough will increase noise, so will over packing it. You can see past threads for material and density, but while glass roof insulation, rockwool, and wire wool have all been used, from what I have heard im happy to just uses acustafil and pack to the manufactures recommendation.

Ramming wire wool up the tail pipe (and you don't need much) is a temporary cheap and dirty bodge to get you through static noise test if you done have a good enough silencer and shouldn't be on the track (not that I haven't don't it once myself) but ruins all performance and typically doesn't last a lap.


Daniel

corrado vr6 - 4/9/13 at 05:53 AM

Cool thanks guys,

I should have mentioned its only to help me get through IVA, but drilling the 4 rivets on my silencer isn't to difficult anyway.

Cheers Greg

adithorp - 4/9/13 at 06:34 AM

Lots of ways to do it but the easiest is to use one of the silencer refill packs from CBS

Drill out rivets and remove end cap, remove remnants of old wadding, insert refil, pull out cardboard tube, refit and rivet end cap. Easy, cheap and effective.

jps - 4/9/13 at 08:05 AM

according to my dad ramming brillo pads into the exhaust of his rally car was a bodge way to get through scrutineering back in the 70s/80s...

adithorp - 4/9/13 at 08:58 AM

quote:
Originally posted by jps
according to my dad ramming brillo pads into the exhaust of his rally car was a bodge way to get through scrutineering back in the 70s/80s...


When I did SVA the inspectors told me about a guy who'd failed the noise test so they went for a brew while he "fixed it" by stuffing wire wool up the tail pipe. He then passed on noise but halfway through his speedo test a whole load of glowing wire wool balls shot out. They said it looked like rats on fire.

When people talk of using wire wool when repacking it's usually to wrap a layer around the perforated tube before the wadding It stops/reduces the wadding getting out gradually thrugh the tubes holes. The CBS refill has a layer of it.

dhutch - 4/9/13 at 09:49 AM

quote:
Originally posted by adithorp They said it looked like rats on fire.

I can vouch for this.
- That and the fact that if you walk around the back straight of snetterton, its littered with wire wool.


Daniel