Engine bay noise suppression material

[steve b]

Hi all ,

 I've seen in a number of threads in the past with recommendations for engine bay noise suppression material , could someone remind me of the supplier please ? I'm thinking self-adhesive closed cell foam with an outside layer of heat reflecting silver .

Thanks

Steve b

[monkie]

I've used dodo mat. Got it from their ebay shop. 

[FridgeFreezer]

Not sure if this exact thing is engine-bay-proof but I lined the trans tunnel with it and it was very good for heat & noise:

CAR Insulation - Sound Proofing Heat Insulation Material

[steve b]

 That's the stuff I had in mind , thanks FF

cheers

Steve b

[FridgeFreezer]

For info, I scraped all the mud & cack off, then wiped the panels down with brake cleaner before sticking it and it's stayed put so far with no additional support.

[Anderzander]

FF, I was thinking of using this stuff you used in your ambulance:

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F252376922308

[Pappa Smurf]

44 minutes ago, Anderzander said:

FF, I was thinking of using this stuff you used in your ambulance:

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F252376922308

That's what I've used on my trans tunnel and cab side of bulkhead. It works fine and underside of bonnet. Nothing amazing.

Edited August 27, 2019 by Pappa Smurf

[Snagger]

Don’t bother - save it for the cab; lining the engine bay makes the vehicle quieter outside but does little or nothing for noise in the cab.  Lining the cab is what you need to focus on.  I learned that the costly way with hundreds of pounds worth of useless engine bay lining (premium stuff at that).  There is a YouTube video of a guy fitting various under bonnet kits to a Defender (Canada, I think) and testing the vehicle with a decibel-meter, and he came to the same conclusion.  I wish that had been posted before I wasted that much money.

[Pappa Smurf]

1 hour ago, Snagger said:

Don’t bother - save it for the cab; lining the engine bay makes the vehicle quieter outside but does little or nothing for noise in the cab.  Lining the cab is what you need to focus on.  I learned that the costly way with hundreds of pounds worth of useless engine bay lining (premium stuff at that).  There is a YouTube video of a guy fitting various under bonnet kits to a Defender (Canada, I think) and testing the vehicle with a decibel-meter, and he came to the same conclusion.  I wish that had been posted before I wasted that much money.

Underbonnet insulation has to be used in conjunction with cab insulation. The Canadian guy had no cab insulation. He also only I insulated the bonnet and fitted an engine blanket, it is the bulkhead that needs the I insulating, in the cab and the engine bay.

[steve b]

The inside will be done too , once the replacement Bulkhead is installed , it's as much about keeping it looking factory , or close to it under the bonnet as anything . It's what the client wants and it will certainly do no harm to add it .

cheers

Steve b

[Anderzander]

My plan is to do the underside of the floor plates, tunnel, and seat box in the 80. Most of its noise is from the gearboxes - if I can do something to reduce that it will make a big difference. Putting it underneath will keep the factory look too.

[ianmayco68]

Has anyone tried or thought about filling the cavity part of the bulkhead with something ? Like some sort of building insulation foam .

[steve b]

Really bad idea , they rot out quickly enough as standard . Also most of the BH is single skin , certainly close to the source of noise .

Not pretty to see  , and 10's of hours to get to this point stripping out too

This is the first time I've had to disc cut the wiper motor clamp strap to remove a wiper motor .....

cheers

Steve b 

[Pappa Smurf]

1 hour ago, Anderzander said:

My plan is to do the underside of the floor plates, tunnel, and seat box in the 80. Most of its noise is from the gearboxes - if I can do something to reduce that it will make a big difference. Putting it underneath will keep the factory look too.

Careful with that, you could trap water and cause rust. Your best best would be to get the Wright off road rubber matting system.

[Tanuki]

TD5-onwards Defenders have a semi-decent soundproofing of the bulkhead, the footwells, the seat-boxes and transmission-tunnel. Can you perhaps replicate this?  Remember that a lot of the noise is radiated from the bellhousing/gearbox/transfer-box, and the big silencer-box that sits under the passenger-seat.

Soundproofing on the underside of the bonnet is worthwhile - a lot of noise is radiated that way, where it then comes in through the windscreen and the vent-flaps.

[to prove it, listen to the engine with the bulkhead air-vent flaps open, then close them and see how the noise-level reduces. Aim to make this better]

I noticeably improved the [relative] quietness of my TD5 by attaching some thin 'cow mat' rubber to the insides of the vent-flaps, as well as replacing the rubber seals round the flap-edges so they actually made an air/noise-tight seal.

[Anderzander]

49 minutes ago, Pappa Smurf said:

Careful with that, you could trap water and cause rust. Your best best would be to get the Wright off road rubber matting system.

I’ve thought about that. They don’t do the wright off road for the 80” - and it would spoil the look a bit I think too.

I was thinking if I got good adhesion, to well painted alloy, from water and heat proof stuff ... then I should be ok ...

[Pappa Smurf]

11 hours ago, Anderzander said:

I’ve thought about that. They don’t do the wright off road for the 80” - and it would spoil the look a bit I think too.

I was thinking if I got good adhesion, to well painted alloy, from water and heat proof stuff ... then I should be ok ...

You could make your own rubber matting system using industrial rubber sheets cut to shape. The good thing is the matting is instantly removable. So when your driving and want quiet, put it in. When you want the standard look, take it out.

[Snagger]

On 8/28/2019 at 8:33 PM, Pappa Smurf said:

Underbonnet insulation has to be used in conjunction with cab insulation. The Canadian guy had no cab insulation. He also only I insulated the bonnet and fitted an engine blanket, it is the bulkhead that needs the I insulating, in the cab and the engine bay.

But I do, and the cab insulation does all the interior noise deadening.  Adding the underbonnet stuff made no perceptible difference.

[Pappa Smurf]

12 hours ago, Snagger said:

But I do, and the cab insulation does all the interior noise deadening.  Adding the underbonnet stuff made no perceptible difference.

Did for mine. I used a decibel meter and it done 4 decibels. Which might not sound like much, but combined with the reduced decibels from the AT tyres and the reduction of noise from vibrations, it does make a difference to comfort. Remember, a lot of noise is at low frequencies that you can't hear, but you feel, dampening that noise helps with the general comfort of your drive.

[Gazzar]

Ordinary glass has very low sound absorption properties. Laminated is better, heated likewise, but overall you are better served by stopping the sound getting to the windscreen in the first place.

I've found under bonnet sound proofing effective, I used 3 layers of "flash band", a tar based product used to seal gutters and roofs, on the underside of my series bonnet, fitted with a TDI engine.

This, coupled with a similar treatment on the engine side of the bulkhead, had made the cab into a loud, but civilised place. Conversations are possible at 60 without shouting.

When I get the Wright off road mat fitted, and a higher ratio transfer box, I think it will be quite good.

Sound proofing is cumulative, it all adds up.

 

[monkie]

In my experience most of the noise comes from body panels acting like a drum skin. The biggest difference I found was in soundproofing the seat box. I painted the underside of the floors and gearbox tunnel with a sound deadening paint from frost, stripped the doors and added sound proofing to the inside of the door skins, and then on the inside of the roof. I used dodo mat with 12mm closed cell foam on top.

[Anderzander]

23 hours ago, Pappa Smurf said:

You could make your own rubber matting system using industrial rubber sheets cut to shape. The good thing is the matting is instantly removable. So when your driving and want quiet, put it in. When you want the standard look, take it out.

If I did it - it would look horrendous. I have stable mat as flooring in the rear tub - and thickish rubber floor matting.

I’ll look further into the underfloor waterproof stuff and see what I can find.

[FridgeFreezer]

I just did the transmission tunnel to knock the whine of the overdrive down, the V8 is quiet and smooth enough already

[Pappa Smurf]

4 hours ago, Anderzander said:

If I did it - it would look horrendous. I have stable mat as flooring in the rear tub - and thickish rubber floor matting.

I’ll look further into the underfloor waterproof stuff and see what I can find.

You should have more faith in yourself. You just need to take your time. Make good template before cutting the rubber out, with a sharp Stanley knife. Then piece it together with heavy duty dict tape on the rear. Just be as neat as possible. 

[Gazzar]

Use a steel rule as an edge to cut against.

Clamp the rule thoroughly, as the risk is that it moves whilst you are cutting.

A tippex pen is a good way of marking out.

Use plastic angle-section edging to stick stuff together and to hide minor imperfections. Tiger seal will ensure its a permanent assembly.