SOUND PROOFING ROOF

[voltron]

Because of the wind noise I would get from my roof rack, I decided to see what insulating the roof would do to reduce it. Reading the forum with mixed reviews I decided to use the Dynamat directly onto the roof to reduce resonant frequency. Then used 3 layers of 4mm EVA foam to help block noise, and also used dynaliner which I stuck to the inside of the roof lining to add more density to the sound blocking efforts. These weren't all sandwhiched together and suprisingly there was a fair gap between each material to provide that air layer of noise reduction again.

AFter a bit of messing around getting the lining back on I took it for a drive and it was hard to notice much difference. I headed to sydney the following week and once I hit the F3 it didn't really sound like that there was a great deal of difference in noise reduction, that was until an hour later and I hit a brand new patch of smooth bitchumen and everything went nice and quiet. I could only just hear the wind noise from my roof rack and other then that, it was relatively nice and peaceful. I would get a hum from my front runner rack at times also and that was only just audible when it happened.

This made me realise 2 things. Just how quiet the PUMA motor is when on the freeway and how much of that noise I was getting before, is coming from the road/tyres. I was going to do the firewall as well but I don't think there is any need to. Whilst accelerating I realise there is a lot more engine noise but once cruising it's relatively quite.

How do you reduce the road noise??? Tyres maybe, I'm just running the standard Continentals at the moment and I thought they would have been relatively quiet. Are there quieter tyres available??
I'm not sure insulating the underside of the wheel wells is going to help a great deal but I guess it's worth a try.

Anybody had great success insulating this area??

cheers

[alittlebitconcerned]

Well there are these things...

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Not a road noise solution but you might consider looking at an engine blanket. I put one on my 2.4 and it noticeably decreased the diesel clatter. Surprising considering its size.

[turbo6i]

Hood liner and lining over the gearbox and footwell decreased noise considerably .

[Dorian]

I haven't done the roof yet but have completely done the floor area. I recon about 80% of my noise reduction came from Dynamat and foam over the rear "wheel arches" and dyna mat on the fire wall, front foot well and transmission arch.

[Cracka]

I removed the rear seats in the 90 to fit out for touring. I used Stinger Roadkill, its the same type of product as Dynamat. I did all of the floor area and side panels to the underside of the side windows and what I could get in the rear door as well.

When I installed my Hannibal rack I also got some wind noise (contrary to all the reports I read) so I removed the headliner and covered the entire roof with the Roadkill and then a layer of 10mm formshield which is a closed cell foam with ally backing, I used the self adhesive version, I don't hear the rack noise now :D

With all of this and my storage unit in the rear my 90 is as quiet as a mouse, even the mechanics at the dealer last service commented when they test drove it.

I also just did a mod to my cubby box and while I had it out I used the Roadkill under the gearbox cover plate, that combined with my 'mod' also made a difference.

My Son was home from Darwin last week and commented that it was actually quieter than his 07 Triton.

So to your question Voltron, I don't think insulating the underside of the wheel boxes will make a lot of difference if you intend to use rubber matting or similar, it will stop the 'holy s--t' what was that when you get the rocks thrown up. You could use a spray type underbody deadener maybe, but for my purpose and results the dynamat type product and then the storage unit over the top achieved what I needed, quietness from road noise AND the rock strike racket is down to a minimum.