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Bonnet sound deadening

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So I've seen some insulation/sound deadening on eBay. It's sayes won't fit if you haven't got correct bonnet.

So does this mean it won't fit mine?

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There is a LR Genuine part to fit the bonnet, or use one of the self adhesive sound deadners like noise killer or dynamat. 

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Edited by western
Parts page added

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The Land Rover part is hopeless. I am going to use the stick on type that you cut to fit yourself

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Defo DIY!  Did my own with 'closed cell foam' and "Sticks like..." adhesive (The one that will tolerate 300 degrees  😀).

Worth mentioning that perhaps a fire retardant material might be better with petrol power but as for my 300tdi diesel...  😁😁

Not pretty but definitely makes a difference imo - the bonnet sounds nice and solid when tapping or shutting and the engine is a bit more quieter

I'll be going egg carton shaped sound absorption material in and around bulkhead/engine bay wun day!  🤥

or I'll change back to a nice quiet petrol!!  😱  (where it's louder at the back!!!)

Worth sorting any rust or painting on the underside of bonnet b4 fixing tho! 😎

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Thanks all that's useful information

Whilst on with sound deadening, I want to do my lt77 seat base, the good stuff is quite pricey. But have seen some pretty new stuff from a puma? , Ok I know R380 ones leave a massive gap when fitted to lt77. But just wondered if the later puma type is closer? or no good.

Thanks

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I did my 90" like 15 years ago or so.

Under the bonnet I cleaned away all rust and applied rustproofing. Then I went to the local boat-shop and obtained some foam-engine-room-insulation, its thick, dense foam with aluminiumfoil on one side and self-adhesive on the other. Hard to set on fire as well, which is important for an engineroom. Cut to fit with a knife. Has been working fine since then.

The seatbox got the ExmoorTrim offering. A wellfitting Heavy-Duty lead-rubber overcoat for the seatbox, gearboxtunnel and floor. I've been very satisfied with the product.

These two together reduced the noise in the cabin significantly.

 

 

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18 minutes ago, tychoS said:

I did my 90" like 15 years ago or so.

Under the bonnet I cleaned away all rust and applied rustproofing. Then I went to the local boat-shop and obtained some foam-engine-room-insulation, its thick, dense foam with aluminiumfoil on one side and self-adhesive on the other. Hard to set on fire as well, which is important for an engineroom. Cut to fit with a knife. Has been working fine since then.

The seatbox got the ExmoorTrim offering. A wellfitting Heavy-Duty lead-rubber overcoat for the seatbox, gearboxtunnel and floor. I've been very satisfied with the product.

These two together reduced the noise in the cabin significantly.

 

 

Was it this one you fitted?

https://www.exmoortrim.co.uk/catalogsearch/result/?cat=0&q=EXT009-12bk

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I have that Wright Off Road matting in my Tdi powered 109. It is very effective for noise and heat insulation and looks very good too.  Easy to clean and take care of, very resilient.  I’d recommend that far more than anything in the engine bay, which really only reduces noise outside the vehicle.  Some dynamat or similar on the seat base and the bulkhead underneath that matting kit would be even more effective, but don’t bother in the engine bay - it’ll degrade with heat and fumes, trap water, and provide little acoustic benefit inside the cab.

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Another important step in the sounddeadening process is to to find and plug each and every hole in the firewall.

Any missing grommet or unused bolthole between cabin and engineroom will transmit noise.

Meticulously find and plug each and every one of them.

Same for any rustholes in the footwells, get them welded up.

 

Edited by tychoS

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20 hours ago, tychoS said:

Another important step in the sounddeadening process is to to find and plug each and every hole in the firewall.

Any missing grommet or unused bolthole between cabin and engineroom will transmit noise.

Meticulously find and plug each and every one of them.

Same for any rustholes in the footwells, get them welded up.

 

Good advice...my bulkhead is in quite good order but does need some work in the foot wells. Will have a look to see what holes to seal up.

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On 2/12/2020 at 9:03 AM, PaulN said:

Defo DIY!  Did my own with 'closed cell foam' and "Sticks like..." adhesive (The one that will tolerate 300 degrees  😀).

Worth mentioning that perhaps a fire retardant material might be better with petrol power but as for my 300tdi diesel...  😁

See, my abiding image of bonnet sound deadening is the stock TDi stuff falling down and laying itself across the top of the red-hot turbo :o. I'd suggest that anything you stick in your engine bay should be fire-retardant as car fires are no fun.

That said, I'm not entirely convinced that insulating under the bonnet makes a huge difference to people inside the vehicle as much as just making it sound less rattly to passing pedestrians.

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The genuine under bonnet stuff is fire retardant and held in place by rivets and hoofing gert washers

Seeing as how you have a 200tdi - get a 300tdi engine sound proofer thing and cut it to fit - big difference, then use 'Dead Mat' tiles (10"x 10") for the bulkhead, then cover with a Wright Off Road doofer

 

 

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6 hours ago, Nonimouse said:

The genuine under bonnet stuff is fire retardant and held in place by rivets and hoofing gert washers

Seeing as how you have a 200tdi - get a 300tdi engine sound proofer thing and cut it to fit - big difference, then use 'Dead Mat' tiles (10"x 10") for the bulkhead, then cover with a Wright Off Road doofer

 

 

Another one for the genuine stuff, I've had a 2nd hand 300tdi one (i think) installed for the best part of 8 years I guess and its great.

Sound proofing is all about increments, people look for a" cure all" sound solution, but its not as simple as that. you have to work at it and chip away, cover any bit of exposed panel, bung up holes, put bits of carpet it, screw everything down as it should be (or add more!) wrap stuff in soft material type tape... list goes on,  noise on a landy comes from various places, inc engine drive train, road noise from tyres etc.I got to a point where you could actually hear where the "holes" in the sound deading where, I've worked really hard to combat the sound issues in my truck and I'm pretty chuffed with how it now is.

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There are some great pointers made already, i'll add a few more.

 

Sound is directional until you hit lower frequencies and with engines, gearbox's, drivetrains, road noise and all sorts of other things, one type of sound deadening will struggle to eliminate all noise.

You need to incorporate various types and understand it's usage.

 

Stiffening panels is a good start.  Using products like silent coat or dynamatt will help in this way but use it sparingly.  Pictures of footwells or the underside of the bonnet plastered in the stuff is purely a gimmick for you to part with your cash.  Any company doing this deserves avoidance. You want to stiffen the panel, so add 2-3 inch strips until the panel has a more ' dead ' sound rather than a tinny sound.  Remember these products don't stop sound travelling through, they provide stiffness and thus help reduce flex and vibration which comes across as ' noise '. ( point to note, the product can provide a barrier to noise as they have mass, but it's tiny and would prove very expensive to use it to eliminate noise alone )

Foams like a closed cell foam help absorb it's effects but they work best when left exposed.  If you cover up a foam then you reduce it's ability to soak up noise and here is where it becomes a little difficult to balance everything with foam and stiffening alone.

The final part is Mass.   Providing a mass that will help absorb sound is another way to quieten things down.  Using dense rubber stuck to the panels underneath a layer of foam will help quite alot.   I've used rubber mat's to drop the lower frequency ( bass from a speaker ) from travelling through walls etc. 

 

I would use a stiffener to the panel first, then a dense rubber mat and finally a closed cell foam on top.  This work's in the cab area very well but it also highlights other problems like the seals around your doors as suddenely they are much more noticable.


For the bonnet, i really wouldn't waste any money on it personally.  The noise outside the vehicle is not going to change the noise you hear inside..the engine is sat in front of you with a thin piece of metal to stop the noise between you and it.  I stripped out my dash and found land rover's idea of sound deadening laughable as it wasn't even covering the multitude of gromets and holes in the bulkhead and of the square meterage of bulkhead, about 40% was covered by their effort from the factory (2011 model ).

 

Landy's were designed to be workhorses, they were never designed to be quiet inside but you can get them to a decent noise level in the cab with some simple practices.

 

A few links to help;

https://www.amazon.co.uk/gp/product/B00BSBMFBM/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1  

https://www.amazon.co.uk/gp/product/B015RI1GJS/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

 

 

 

 

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My only real issue with all this malarky is that you're basically making the truck heavier and adding loads of things that absorb moisture and hold it near bodywork...

We've got a bit in the ambulance (reflective foam under the tunnel / seatbox and Wright mats in the cab) and it does make a difference - as does not having a rattly old diesel up front :SVAgoaway:

For the 109 I have avoided anything soft at all as it's supposed to be functional and hose-outable.

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As others have said - blocking all the possible noise-passages between the engine-bay and the vehicle interior is really important.

When I got my TD5 90 I spent a bit on a 'soundproofing kit' featuring foam panels with heat-reflective aluminium-foil one side, peel-off self-adhesive sticky-stuff the other. While this worked OK on the top of the centre-area-where-the-cubby-box-lives-between-the-seats, the stuff intended to fit on the *underside* of the underseat access-panels to the battery-box and ECU/fusebox covers had serious adhesion issues, dropping off after a few years - so I re-stuck these to the tops of the access-panels using "Sticks like ****" gloop-in-a-cartridge.

The supplied under-bonnet panels dropped off after less than a year: I guess their self-adhesiveness was not designed to handle underbonnet cook-off-after-engine-shutdown temperatures of an enthusiastically-driven engine.

So I threw the stick-on panels away and instead used the remains of a can of window-fitters squirty-foam to squirt into the holes in the channels between the bonnet-skin and the bonnet-frame itself - the idea being to provide a positive fix between these and damp any resonances in the bonnet-skin. The result was as good as the redundant stick-on panels.

But - to re-use the stick-on panels, I took the bulkhead vent-flaps off and glued cut down bits of the stick-on panels to the inner faces of the flaps. This was inspired by noticing just how much more in-cab noise there was when the flaps were open, and thinking that even when they were shut, noise could come through.

Whatever you do, a Defender will never be a quiet travel-experience. Accept this, and learn to turn the radio up!

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