Jump to content
Click here if you are having website access problems ×

Repacking my exhaust with Acousta-fil

Andy Whittle

Recommended Posts

An Exhausting Tale!

My exhaust had started to get a bit on the loud side! Not being one to deliberately upset the neighbours and also living in an area where a lot of people like riding their horses on the public roads I needed to do something about it.


Using the BlatChat search tool I found many threads about repacking using long strand e-glass, wire-wool, rock-wool etc, etc and a couple of threads about Acousta-fil. So using the power of Google I went to do some research about Acousta-fil; long story short I phoned the manufacturer (http://www.culimeta-saveguard.com/ ) to find out where to buy the stuff. However it would appear they were a little clueless and couldn't sell me small amounts and didn't know who I could get it from!


More Google searching and I eventually found a bike exhaust company called http://www.racefit.co.uk who advertised recharge kits for their bike exhausts which listed Acousta-fil as the repacking material.


So gave them a ring and they were very helpful. The only draw back being that their Acousta-fil comes in pre-cut lengths designed for their small bike exhausts. After a bit of discussion we thought that if I bought enough sections I could easily repack my exhaust. They explained that it's a very easy to use material, can be cut with scissors and is so soft you could make yourself a pair of underpants and wear them all day without get any irritation (unlike the glass fibre packing in my exhaust)! Don't try this at home!


After some estimation we decided how much I would need as each section is 237mm x 672mm, we settled on 10 to give the necessary volume required. At £2.88 a section it wasn't to bad, with VAT and next-day delivery it worked out to be £38.87.


The following is a set of photos showing how it went.

Repacking my exhaust with Acousta-fil


Observations and notes

The material is very easy to use and very quick to do, even including stitching it together to form a long blanket.

It really doesn't itch or irritate your hands as it really is so soft.

You can easily cut it with scissors and shape it to how you want it.

I only used 8 sheets and it was packed very tightly, so the total cost using Racefit supplied material would only be £28 inc vat and delivery (if I hadn't bought too much).

The Acousta-fil is stitched together with thread that melts when in use allowing the material to expand and fill the exhaust can.

I was told I didn't need to use any wire-wool, thus saving money, skin and all the mucking about. Not using it supposedly allows the Acousta-fil to provide better noise suppression especially on straight through silencers.

It should be possible to get the material in the correct width for our Caterham exhausts, however finding it is the hard part. It could be bought in bulk from the manufacturer but I guess you would have to buy loads!


Did it make my exhaust quieter? *rolleyes* Well it seems to have done the trick *smokin*


The exhaust note is a little deeper now as it was distinctly "tinny" before and my kids didn't hear me pull up outside the house after an installation check. Also when I mash the pedal the induction roar from the TBs is louder than the exhaust noise now 😬. I guess as the stitching melts and the Acousta-fil expands the exhaust sound will probably change again, hopefully for the better.


I think it was a success *wink*



I am Leg End...

Link to comment
Share on other sites

Having seen that photo I think so too ! Easily rectified though.


I may see if I can get some guidance from either the manufacturer or bike exhaust guys tomorrow and then remove any excess Acousta-fil.


Not sure what the effect of over packing would be? Any scientist offer a theory? *rolleyes*


I am Leg End...

Link to comment
Share on other sites

At Abingdon last month one of the guys had a noise test issue so we opened up his repackable exhaust, unrolled the sound deadening material, took some out, and packed it back in loosely. Result was it passed the noise test. So I think overpacked = louder.


I'm no scientist but I suspect that if the material is too dense it just transmits the noise to the outside of the can rather than absorbing it.

Link to comment
Share on other sites

I too am about to install acoustafil into my standard R3/4/500 silencer. I also contacted them and spoke to Steve Shaughnessy there Technical Director, who was very helpful. He told me that if I could tell them the length/ outer diameter and inner perf diameter they could work out how much fabric was required.


So in my case (using their higher grade Fabric S2 Glass, my choice after reading this)

Length: 500mm

Outer Diameter: 150mm

Inner Perf Diameter: 65mm.


Fabric Style: S2 Glass


Fabric Weight: 1000gsm

Weight per lin Metre: 500 g

Fabric Length required to fill at 150g/litre: 2.15 metres

Price per metre £9.00 plus Freight (£10)


They manufacture there fabrics in various widths, and can sell it by the metre, and supplied me with the length above, so no need for stitching!


Will give up date once fitted




Link to comment
Share on other sites

I about to move to a quiet can for the track and keep my load exhaust for the road as I think its safer as people can here you coming, yes I slow down for the Gee Gees but I would rather the dosing Micra driver gets a wake up


Nick h


Fuel your Addiction here

Link to comment
Share on other sites

Hi Jon (Low Flying..)


Thanks for your information *thumbup*. I believe I probably have the same stuff as you, I have weighed it and it's near identical in terms of grams per linear meter. Also the invoice lists it as 150g.


After doing a few scrapbook calculations I worked out that I needed 1.84m to give 150g/litre. I have repacked with 1.835m so not far off, more by luck than judgment and subject to my schoolboy maths.


I will be very interested to hear about your experiences with wrapping 2.14 metres into your silencer, especially as mine was quite full with 1.835!


cheers Andy


I am Leg End...


Edited by - Andy Whittle on 30 Mar 2009 14:20:27

Link to comment
Share on other sites

Hi Paul, sorry I have no idea. *redface*


However as the material is basically very fine strand glass-fibre in a "different" method of presentation it should be similar to the more usual e-glass. There is no mention of was happens to it as it deteriorates on any websites I've found, some say it lasts longer though *rolleyes*.


cheers Andy


I am Leg End...

Link to comment
Share on other sites

  • 1 month later...

Hi Andy, Jon (Low Flying ...),


How is this going now. Has it bedded in and do you think you bought the right volumes of Acousta-fil. It looks like I have the same silencer as Jon on my R300 so ordered the same amount.


I was told that the grade or name for the top spec product has changed. They now refer to it as ZT1 Fabric but has the same weight and temp rating as the S2 Glass.


Apparently it is quite a pain for them to set up individual accounts for our small purchases, they normally deal with businesses buying in bulk. Perhaps some one would like to set up bulk buy if this proves to be a good product.



Link to comment
Share on other sites

Looks like I just had the same conversation.


Seems what Zentrum is the new name for the the stuff recommended for us - higher temp rating for longer life - less chance of it melting and failing.


So, while I've just placed an order for enough for me, if anyone else near to me, or can come to me, or can pay postage from me, I can boost the amount and distribute it out - maybe with a quid or two on top going to NTL? Postage from me at cost and hopefully I can find enought previously enjoyed wrapping materials at work for the cost of those not to come into it.


To fill a 600mm long, 150 OD, 50 ish tube through the middle, silencer (ie Powerspeed type), 1.47kg is needed, @£18 a kg - plus carriage, plus Gordons share for all the TVs, mortgages, duck-houses etc.


Any interest, indicate below and we'll go from there.


Vicki at Saveguard is away of this thread ( *wavey*) and I mentioned I'd stick this on here and see what happens. Although we might have a way to go to get her more usual order quantity of 100's kg . . .



Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...