240
My understanding is that later 240s have better sound deadening than the early ones, but my 1992 240 is still louder than I'd like. The main noise is from the engine, but better (firmer) suspension was recently fitted and there's now a lot more road noise too.
I noticed that my car is missing the piece of foam deadening at the top of the firewall (as in where the strut braces bolt to). Will replacing this make a difference?
What worthwhile improvements can be made?
jamesinc
Get Dynamat and line the inside of the cabin with it. World of difference.
240
As in the doors, or under the carpet + behind the dash too?
jamesinc
Boss mode would be to cover everything completely. If you want to spend less, the centre of large panels is a good spot. Door skins (inner and outer where possible), footwells, all around the rear wheel arches, and up the cabin side of the firewall. It will make things quite a bit quieter. It will also improve the apparent quality of your radio if you put some around the speaker holes.
240
Sounds like something I should probably do then... must the dash be removed or can it be done with it in place?
Vee_Que
To do it to reduce noise, the dynamat or similar stick on sound deadening is the first barrier, to reduce engine and road noise, lots will come from the rear wheel arch area.
But once you apply more stick on sound deadening you need a insulation matting. My 122 has that and I've pictured it in my cars thread.
Carbuilders.com.au is a good source.
240
So the insulation matting is applied over the dynamat?
Vee_Que
Yes, but you do not have to use dynamat brand material. The ones half the cost do the exact same job.
240
Yeah I figured. What's a good price for that stuff? It's $200 on ebay for 9 sheets (3.3m² total)
jamesinc
You don't need to put another layer over the deadening, assuming you're retaining the old foam underlay. Otherwise you can get rolls of high build underlay really cheap from Knox Auto Carpets. They deliver too.
Vee_Que
i disagree James, the tar deadener is not to reduce the audible noise you hear, but to reduce drumming of panels etc. The factory foam underlay is not very heavy and does not reduce noise vs the knox auto carpets insulation, which is what I bought for my 122 when it was on runout, or this :
http://www.carbuilders.com.au/acoustic-liner-interior-stage-2 which would target the noise he is trying to be rid of.
They have the stick on "stage 1" stuff, 3.6m² for less than $200 and they have an ebay store.
I had a 1984 single cab hilux, tar matting followed by land rover discovery underlay which was the right shape etc, I could talk at a normal level in the cabin, the underlay made the difference to reducing the road noise.
jamesinc
I've run just tar and it works - hugely. A huge, unmistakeable difference in road noise. Any material that reduces panel vibration also reduces road noise, because that is how sound passes through the panels.
jamesinc
Though I won't deny if you run dense underlay as well as tar deadening, I'm sure it'll do even more, but I'm just saying the tar on its own does a great deal.
Vee_Que
As we both know, Volvo already run sound deadening that reduces harmonics in panels, even my 122 donor car has it all the way through, and I'm certain 240's already have it, as my 264 did.
jamesinc
Yeah but they run small squares of it. The kits you buy have enough to cover most everything.
Vee_Que
Having done research on this, there is no need to cover everything with the tar matting, as it's reducing drumming, once that job is done, then the underlay does the real work....
Spac
If you want to quieter down a 240, then replacing the redblock would help... :/
The gear lever boot can be a significant source of noise on 240s. Check the foam underneath is intact. I've doubled up two worn bits of foam with good success.
A piece of old inner tube under the rubber boot can also help, especially if you cut the hole small, so it fits tight over the gear lever (I've done this on non-Volvos and it's worked well, but I think the Volvo foam works better).
A_Volvo_Driver
My car needs a LOT more quiet!
Ex850R
Tar paint.
Pond sealer.
Roofing aluminium and sacking, plumbing flashing stuff.
All good and cheaper than dynamat type stuff.
jamesinc
@Vee_Que, if you want to run multiple layers, by all means run tar -> foam/felt -> MLV (mass loaded vinyl), but if you're choosing one, tar will yield the biggest difference. This comes from having used varying combinations of OE deadener, felt deadener, and tar deadner in current and past Volvos.
The OE underlay on 90+ (ish) 240s is foam with MLV skin, that stuff is great, I found it outperformed the Knox Auto felt that I put in the '77 244.
Ultimately to make the carpets feel nice underfoot, and contoured correctly, you'll need a high build felt underlay. My advice would be take that from a late 240, and go nuts with the tar deadener on the door skins, arches, cabin side of firewall, and floor pan. A couple squares on the roof might help but removing the liner to do it is annoying.
