Here's my writeup on the noisekiller - but like has been said - you could probably do most of it yourself off ebay (boot and underseat - even bonnet perhaps)

http://www.wastedspa...er-for-octavia/

Does the heat-proof bonnet liner go back over the soundproofing?

Professional soundproofers will not touch the Octavia's doors - far too many electrical and audio gubbins which could be discombobulated. So unlike my first Renault R4, which I treated to a soundproofing kit with amazing results - well, it couldn't have been any noisier....

Edited 23 February, 201313 yr by JohnMorr

To properly treat the octavias doors you need to remove the inner skin by drilling out the rivets and line the outer door skin with deadening. This will help to reduce any rattles from the door (wont reduce road noise though). Refit the inner skin then do the same to the inner skin.

There isnt much point touching the doors is all you want is reduction of road noise as most of what you hear at the doors is from seals (might be worth replacing them) and the design of the car creating wind noise.

Best place to treat with MLV's is the boot floor, arches and main floor of the car from the foot well back.

Like I said, there isnt a cheap way of doing it. You can try it with underlay which does have a small affect and its too pricey but it wont get any miracles.

If you do want to try the underlay option have a look at cloud 9 underlay

Does the heat-proof bonnet liner go back over the soundproofing?

Yeah, if you have a look it just clips onto the underside of the bonnet - have a look under it you can see al the bracing and the skin of the bonnet, the self adhesive bits go between the bracing to help deaden the racket.

Deadening is really the key word, we are trying to stop bare metal from resonating in as many places as possible; this is why IT DOES work a little for road noise, since although the noise is coming up directly from the tarmac=>tyres=>chasis , if the metalwork / panels can't vibrate they simply don't allow as much of the sound through.

The noisiest 3 sets of tyres I've ever owned were Bridgestone.

I've been through a massive noise reduction effort in my tin-can work car with decent results. For the best outcome you need a 3 step approach.

Step 1. Dampen the panels. This is by sticking anything soft and heavy to them to stop the vibration. Lead would be awesome, but dynamat and roof-flashing tape do the trick. This doesn't need to be full cover. Just enough to stop the buzzing.

Step 2. Insulation layer. This needs to be full cover and closed cell foam (EVA foam is good and affordable) is best. It stops vibration on one side becoming noise on the other.

Step 3. Top layer. This is best with mass-loaded vinyl. But even carpet or plain vinyl will work. The idea here is a top layer that kills the last of the vibration coming through.

My Scout is quite good for road noise. It's no range-rover but for a car it's excellent.

Ive bought a 1mtre roll of this

 

http://www.carinsulation.co.uk/product/heavy_layer_felt_laminate_insulation

 

which fits fairly neatly under the boot floor with minimal cutting. Its made a noticeable difference to the noise and Im chuffed for under £20

 

 I will look at floor carpet underfelt next

Don't think there is a miracle cure. Tyre noise is the dominating source and comes through the whole structure IMHO. I've used the stick on stuff under the back seat and the spare well without noticing a significant difference.

 

Turning the radio up is really the most effective solution- honestly!

I've been through a massive noise reduction effort in my tin-can work car with decent results. For the best outcome you need a 3 step approach.

Step 1. Dampen the panels.

Step 2. Insulation layer.

Step 3. Top layer.

.

This. Get all the floor in the rear and the arches and this makes a big difference. I did it on a colt I used to have and the difference was quite big. Don't get me wrong it wasn't silent but was tonnes better.

If you get all the material from car audio places online and avoid brands (ie dynamat) you can do this relatively cheaply if you are prepared to do the cutting and sticking yourself.

when trying to reduce noise you need to decide what you are trying to reduce. Different products are designed to reduce different frequencies which is why many people buy stuff which doesnt work as its the wrong product.

 

As above, really you need to go all out or nothing to get a good result

Regarding road noise, I notice that Superb 2s (and Octavias?) have no lower rubber spring seat on the front suspension struts. The current Passats don't either. (Unless they're so discrete that I can't see them).

 

Most other cars that I've looked at do have these installed, e.g. Mondeo, 407, anything Citroen  and many, many others.

 

I imagine this part is to stop the spring creaking, but must also improve road noise isolation a bit.

 

Anyone have any idea as to why VAG have left it out on these cars, apart from cost?

 

I know that there is still a rubber seat at the top of the strut, but others have both.

 

Do you think they could be retrofitted somehow?

Edited 14 December, 201312 yr by CombatWombat