Soundproofing insulation

[fla 9]

I thought I'd put a few pointers here as there's a lot of misleading info on the internet.

So here goes:

Noise in the cabin comprises low and high drequencies, low are the road noise rumbles, higher are the wind and air noises

Isolation, damping, absorption, blocking are different characteristics that need addressing

Damping stops panels vibrating and this is done with damplifier et al products stuck to the outer skins

Absorption is achieved by using dense open cell foam

Isolation is separating the vibrating layer from a blocker or absorber and is usually done with a closed cell foam. This does not really assist much in noise absorption

Noise blocking is achieved using a mass layer typically mass loaded vinyl is used. This needs to be separated from the vibrating layer eg door skin, floor panel.

 

The ideal setup is to use a small amount of vibration damper per panel. Then use a thin 3-5mm layer of closed cell foam. This should then be covered with around 10mm of dense open cell foam and finally a mass loaded layer of 2-3mm should be laid over everything.

If we had enough space under the carpet it would be ideal. Sadly we dont and i am just trying out a 6mm and 10mm thick.open cell foam under the carpets without a ccf but with a mass layer on top.

 

I wouldnt really waste time and money on roof flashing or carpet underlay - the latter is good for impact noise reduction ie walking.

 

Hope that clarifies things a bit.

Edited December 28, 2019 by fla

[Keyo 47]

Thanks that does FLA.

[Keyo 47]

Can I ask has anyone ever tried putting the carpets in the washing machine on something like a wool wash 30 degrees. Did they come out OK or shrunk or damaged.

[Keyo 47]

FLA do you have to glue the first layer of insulation to the internal floor pan ? Thanks

[seanl82 23]

Can I ask has anyone ever tried putting the carpets in the washing machine on something like a wool wash 30 degrees. Did they come out OK or shrunk or damaged.

 

I put mine in a large industrial drum washer. Washed quite well though some of the grit stayed inside which needed hoovering when dry. No noticeable shrinking or anything on a 30 degree wash. I gave them a bit of a dry scrub after to loosen the pile as it felt a little stiff as well.

[Keyo 47]

I put mine in a large industrial drum washer. Washed quite well though some of the grit stayed inside which needed hoovering when dry. No noticeable shrinking or anything on a 30 degree wash. I gave them a bit of a dry scrub after to loosen the pile as it felt a little stiff as well.

 

Good stuff not sure a domestic washing machine will do them any good then due to size.

[robrado974 1]

Great info , thanks Hasan .

I put my old carpet in the washing machine and it came out lovely.

The new carpet which I bought from Heritage is not only thicker (hence you cannot use the deluxe underlay)

The seats cannot move backwards or forwards), but also it’s all one piece which makes it difficult to fit .

[fla 9]

Can I ask has anyone ever tried putting the carpets in the washing machine on something like a wool wash 30 degrees. Did they come out OK or shrunk or damaged.

 

You'd need a large machine but i usually just wash them in the summer with some.liquid soap(persil) and a hard brush. Rinse thoroughly and they dry off quickly - they're synthetic so the water just drips through. Hang them on a fence or a couple.of clothes horses

Plus they smell nice too!

[fla 9]

Ah sorry, just noticed the replies above.

[Keyo 47]

Here is a helpful picture.

 

https://cdn.shopify.com/s/files/1/1613/6135/files/CORRADO_UNDERFELT_KIT.pdf?6289193082729557112

[Kevin Bacon 5]

Absorption works best in my experience, having caked my Corrado in 3 tonnes of dynamat type stuff :grin:

 

In my MK4 R32 I stuck a load of studio grade acoustic foam panels behind all the door cards, under the parcel shelf, backs of the rear seats etc and that had a much greater effect on noise reduction.

 

To expand on what Hasan said, if you want to cut overall ambient noise - absorption. If you want to cut drone from exhausts, tyre and suspension rumble - panel dampening.

[James. 9]

Absorption works best in my experience

 

Looking at doing this in the very near future, but don’t know where to start. School me:

 

Which material do I need ?

 

How much do I need ?

 

Where do I put it ?

[Keyo 47]

I stripped mine today.

 

The insulation depth total layer was about 22mm. Was cut in some places to go over the floor pan pattern in the rear footwell.

 

I had a very thin plastic grey insulation pad that had cells that was glued to the floor pan, then about 20mm of insulation with a rubber topping. They were smelly and damp with pink coolant from a previous heater matrix leak, so glad I pulled them out. The drivers sides were still mint to be fair so just left them, no point strippping out trim unless you have to as always a risk of damage to them.

 

My carpet was pretty clean and didn't feel the need to remove it completely as the top layer rubber of the old insulation had protected it. So I just stripped enough interior so I could lift the carpet up from the footwells. In other words I didn't fancy stripping the centre console . I gave the carpet a detergent clean with a VAX dry and wet and came up great.

 

Just waiting for the standard 12mm insulation from Heritage and going to double up the pieces (glue together) as only doing the passenger side that was wrecked by the evil matrix spewing.

 

I would use a flexible insulation that you can cut out to suit any non flat surfaces in the floor pan.

 

Purchased this from Heritage but I would look elsewhere as probably not great.

 

https://cdn.shopify.com/s/files/1/1613/6135/files/CORRADO_UNDERFELT_KIT.pdf?6289193082729557112

 

This looks good stuff and will leave you room for a couple of mm for a thin base sound absorber. Also seller has loads of other materials.

 

https://www.ebay.co.uk/itm/1m-x-1m-20mm-Classic-Car-Insulation-Restoration-Floor-Sound-Proofing-Deadening/252376923704?hash=item3ac2d63e38:g:e6wAAOSwGpBdssMe

 

This is where you fit it same as factory.

 

https://cdn.shopify.com/s/files/1/1613/6135/files/CORRADO_UNDERFELT_KIT.pdf?6289193082729557112

 

This is Corrado factory insulation which is the same I removed from my car. Insulation with a rubber top.

 

https://gramho.com/media/2175337963016226635

 

I'm going to remove the destroyed insulation off the rubber and glue the new insulation to it as will be a perfect template and has also insured the survival of my carpet over the last 25 years.

Edited December 28, 2019 by Keyo

[Storm Warning 0]

Good and interesting thread guys. I've purchased new carpets and the deluxe underfelt from VW Heritage, I'm also not sure of the quality of the under felt comparing to the factory layer. Has anyone used the Spoonfed option? it is going to cost a fortune... but is it worth it? https://www.spoonfedtuning.com/collections/corrado/products/corrado-sound-insulation-kit

[Keyo 47]

It looks great but I couldn't justify spending that much money. You do realise its 325 dollars just for the footwells not including shipping and customs ?

 

At the end of the day factory insulation has lasted 24 years and would of lasted longer if it wasn't for my matrix, it has also protected the carpets Im sticking with OE style. Im glueing the Heritage insulation to the rubber once I've stripped the old insulation off. Also you will see the insulation on the back is glued in several sections with different depth, which you can also use as a template for the new insulation to fit round floor pan pattern. I actually like the rubber as it stopped the matrix wrecking the carpet and the insulation under it mopped it up.

 

Storm Warning please may I ask what is the Heritage stuff like, if it is anything like their under bonnet insulation Im going to shed a tear ha.

Edited December 28, 2019 by Keyo

[fla 9]

Well storm warning they've got their description slightly incorrect the ccf doesn't absorb road noise it basically decouples the mass loaded vinyl from the noise transmission surface ie the floorpan.

Open cell foam absorbs noise.

[Storm Warning 0]

Yeah, realise it adds up to an obscene figure! I'll grab some photos of the VW Heritage stuff and share them. To be honest, I bought it in a big sale a while ago when I bought new carpets too without really looking into the best options.

 

Regarding the under bonnet sound deadening, you saying the VW Heritage stuff isn't good? is it the same as what was on a group buy on here a long time ago? I bought that set, but thinking about running without it all together.

 

Perhaps stretching the boundaries of the subject... has anyone ever replaced the foam wraps on the loom behind the dash? mine has turned to dust and I'm mindful I need to use something to not introduce new rattles.

[fla 9]

I've replaced some with fabric tape (as per the engine bay harnesses), some with strips of self adhesive felt. Still manage to get some rattles which i cant seem to locate

[fla 9]

I've also picked up a few under bonnet soundproofing panels from a breakers yard to see if they can be used somehow..

From a discovery, audi and one other. Might not work but i want to try it out.

[Storm Warning 0]

https://photos.app.goo.gl/Lj89vf62MCg9XNgf6

 

The description on VW Heritage:

 

Deluxe underfelt kit for Corrado, The kit includes 8 pieces to use where no underfelt is present. It is used underneath the carpet

Made from a heavy duty 10-12mm thick felt and cut to shape, this set provides two layers of underfelt for the front and rear foot well areas giving a total thickness 0f 20-24mm in each area.

 

Read that description after took pics, I'll layer them up and compare again (and measure) later today if I get chance. I don't think 2 layers of this will be as bulky as one layer of factory, that said, once you've loads a couple of thin layers off the factory stuff by removing it, may not be much in it. One layer of the new stuff is closer to the thickness of the deadening on the bulkhead behind dash (but not as thin)

[Keyo 47]

The heritage under bonnet insulation is like a vinyl it is so far from been oem, It is not even the exact shape either you have to trim it. I had my under bonnet spotless and fitted it with the glue they supplied. After I fitted I just looked at and thought that just looks horrid, ripped it off and threw it in the bin- the glue they supplied its like a hard glue that I couldn't get off, was really p,,,, off to be honest waste of time and money.

 

I'm not sure if the group buy was the stuff Heritage is selling , have a look at your under bonnet insulation and if it looks more suitable to make a gimps mask do not use it.

 

Do yourself a favour and buy this stuff UK buyer.

 

Has option of 10mm and 20mm

 

 

 

https://dreadnoughtcustoms.co.uk/products/vw-corrado-bonnet-lining-2?variant=12562635915349

 

If the Heritage stuff is just crap for floor insulation and the measurements are not correct i'm just sending it back. By there measurements 2 pieces will be the same as OE as I have measured mine and the insulation is 20mm - must war you the oe insulation does not got right to the edge of the floor pan probable at least a 5 cm gap from the sill.

 

Problem with some of these aftermarket material is exactly that it does not look the quality of OE .

 

I found the C pillars where my major rattle, pulled them off and put some new cloth around the clips that house it, major difference.

Edited December 29, 2019 by Keyo

[seanl82 23]

If you want the bonnet sound insulation, you can't go wrong with the one that sprinter on here sells. Self adhesive and a fantastic replica of the OE stuff. Is it as good an insulator as the OE stuff, I'm not sure but I don't see why not.

[Keyo 47]

https://photos.app.goo.gl/Lj89vf62MCg9XNgf6

 

The description on VW Heritage:

 

Deluxe underfelt kit for Corrado, The kit includes 8 pieces to use where no underfelt is present. It is used underneath the carpet

Made from a heavy duty 10-12mm thick felt and cut to shape, this set provides two layers of underfelt for the front and rear foot well areas giving a total thickness 0f 20-24mm in each area.

 

Read that description after took pics, I'll layer them up and compare again (and measure) later today if I get chance. I don't think 2 layers of this will be as bulky as one layer of factory, that said, once you've loads a couple of thin layers off the factory stuff by removing it, may not be much in it. One layer of the new stuff is closer to the thickness of the deadening on the bulkhead behind dash (but not as thin)

 

Thanks for the photos.

 

Is that one piece or two pieces of the Heritage stuff that you are comparing to the VW OE insulation thickness. If it is one piece looks spot on if doubled up Thanks

Edited December 29, 2019 by Keyo

[Storm Warning 0]

Pictures show just one layer, I'll double it up and look again when I get chance.

 

I'm a long way off rebuilding mine, but already stocking many rolls of loom tape and OE anti rattle tape... Going to see what I can source for foam a wrap too.

 

The bonnet stuff I have looks like OE, not gimp mask like 😂 though sometimes I feel like I'm abused like a gimp when buying Corrado parts.

[Keyo 47]

Great the Heritage stuff should work fine then if doubled up (deluxe set)

 

If you're looking for a 2mm sound absorber to get that little bit extra, I looked at the Corrado part number and this is what is has been superseded by . You get 6 sheets and is described as sound absorber. Probably cheapest place to get it would be the stealers. You could use this as the membrane on the top.

 

Part number 323 863 950

 

https://www.ebay.co.uk/itm/PACK-OF-6-AUDI-VW-SELF-ADHESIVE-SOUND-ABSORBER-INSULATION-SHEETS-323-863-950/192995761122?epid=645164362&hash=item2cef719be2:g:YjsAAOSwXYpdJajX

 

Also part diagram of insulation

 

http://www.oemepc.com/vw/part_single/catalog/vw/markt/RDW/modell/COR/year/1995/drive_standart/76/hg_ug/863/subcategory/173010/part_id/3686226/lang/e#sec_4

Edited December 29, 2019 by Keyo