Sound Dampening Plan For Review

[110_USA]

I'd like to quiet down the cabin noise of the ol' 2.5L Diesel. I'm considering Wright Offroad's system...Here

And perhaps some Dynamat on the horizontal surfaces. I'm wondering of there is enough play in the premolded mat to accommodate some additional insulation underneath it.

Anyone have any suggestions or experience with good sound dampening? I'm guessing most of the sound comes from the seat box and foot wells, can't really tell though, just sounds like it's coming from everywhere.

I would like to go all the way up the fire wall, but that is a bit more involved than I'd like to get into at the moment, perhaps another time.

[landmannnn]

LR tolerances mean that you would need to trim these kits anyway, there would be enough slack to add extra underneath. The kits make a lot of difference.

I would also get one of the blankets to cover the engine too.

Is yours a CSW with headlining? A plain metal roof reflects noise around.

[110_USA]

I would also get one of the blankets to cover the engine too.

Please elaborate, not sure what you're talking about, I'm just imagining a horse blanket wrapped around the engine

It's ex military so it has... well nothing. I have a dashboard and sun visors but that's it.

[landmannnn]

Please elaborate, not sure what you're talking about, I'm just imagining a horse blanket wrapped around the engine

I guess that might work. The exhaust may warm it up a bit though. Seriously, have a look at this site for an example:

http://www.noisekiller.co.uk/materials_more.php

You might find some in your local breakers since quite a few manufacturers use them.

[yellow]

His nearest local breaker probably only has US trucks...

As for the 'blanket', it does what it says on the tim. I have one on my 200TDI and the wife says the vehicle is more silent than a TD5. And the blanket is the only thing I have on there... Still contemplating the Wright Offroad matting.

Also, look for adding heavy material onto the load area in the back, and possibly the wheel arches. Insulating the roof and sides with sift 'fluffy' material would help greatly as well.

[tychoS]

For my 90" softtop I have had great success fitting the ExmoorTrim mat system. It's made of a of really dense and heavy rubbery material. it looks good too.

To supplement this I attached 30 mm sound absorbing foam to the underside of the bonnet.

With these modifications you can converse up to around 90 km/h without yelling and up to 70 km/h without raising our voice at all.

Since it's a softtop I did not have to deal with sound dampening for ceiling and sides. However driving topless is virtually silent apart from tyre noise.

[Bumpyride]

Not sure if it helps, but ive attempted a variety of schemes unfortantley all at once and so i have no real feel for which had the most effect.

1: panelled the backout - with ply wood - the cavity then filled with sleeping matts - to 60% of the depth of the void.

2: 6mm rubber matt lining all around the internal faces of the bulk head and footwells.

3: rubbber lining of the voids under seats - to be completed.

4: filled all cracks and holes with flexibile rubber sealant.

I would certainly like to think it is quiter - however wishful thinking maybe present in view of the amount of work it's taken.

Plan to fit an engine blanket (suggestions of a cheap supplier would be appreciated) - once done will measure the dba attenuation.

agree with earlier comments, the load space needs to be covered if a hardtop, have tried the aformentioned rubber, but it made sliding things in a real mare.

Have fitted series doors, with associated gaps around the frame now plus no door cards to reduce sound - think this is potentially another point to focus on.

i have in professional capacity done a reasonable amount of work looking a soundproofing buildings and industrial plant, the killer is always noise leakage through, any hole, crack or joining of materials. So checking door seals, bulkhead holes etc will always limit the amount of success you have with any scheme.

cheers hope this helps

[landmannnn]

Does it get warm enough in Denmark to drive topless? (you or your lr)

[Eightpot]

Lining the underneath of the floor/gearbox panels with roof flashing tape will make a big difference, especially to the whine from the transfer box & gearbox.Use a couple of layers. As this is under the panels you still keep the military look as well if thats important to you.

Then find some rubber matting to make an engine blanket and floor mats if you don't have some already

That's the cheap way to do it - probably $70 all in.

Otherwise the Wright off-road mats do look very good. I would still use roof flashing tape rather than dynamat as it's a lot cheaper and does the same job.

Plug all the little holes in the bulkhead as well and make sure the floor panels are a good fit.

I reckon doing this I've reduced noise by 40%, especially the high pitched scream from the gearbox at motorway speeds.

[lansalot]

Into the dumpster at your local carpet megastore, get some underlay and apply liberally to cabin.

Does it work ? Not as much as I'd hoped. But then my exhaust has holes in it and hey, it didn't cost me anything

[sparg]

LR tolerances mean that you would need to trim these kits anyway, there would be enough slack to add extra underneath. The kits make a lot of difference.

I would also get one of the blankets to cover the engine too.

Is yours a CSW with headlining? A plain metal roof reflects noise around.

actually, a metal roof panel is a resonant body (like a drumskin) and so, at particular frequencies (the resonant frequencies of that structure) act as particularly efficient mechanical amplifiers. likewise boxes such as the seatbox. That's why they often deaden with bitumin.

then, of course, a relatively small hole allows an extraordinary amount of acoustic energy through, so any holes in bulkhead - around pedals and things - can be significant sources of sound. Finally, body transmission - consider, for example, if the exhaust is actually touching the chassis - it's really loud. So any 'sources' that are fairly hard-coupled to strcutures that can convey the energy should be looked at

regards