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Barney12



Member Since: 09 Jun 2015
Location: South West
Posts: 744
United Kingdom 2014 Defender 90 Puma 2.2 XS CSW Corris Grey
Bonnet Insulation - Install with Pictures.
I had a few hours spare this morning so decided to crack on with my planned bonnet insulation project which is part of a much larger sound insulation project.

Anyhow, I decided on a very crude technical test when I remembered I had an old analogue radioshack sound meter which I used to set up my surround sound system at home. Its a bit crude and I didn't have time to go for a drive and record levels so a stationary idle had to do! So pre-mod the readings were:

Outside (30cm from grill, level with bonnet): 67 dB
Inside (30cm from dash, level with top): 57 dB

On to the job:

Step 1: Under the bonnet was fairly clean. So just a wash off and then a full degrease with panel wipe.

Step 2: Dynamat Extreme (Supplied by Simon from MPS - Top guy to deal with and the best price by far!). Didn't go too mad but applied to the obvious accessible outer sections. I noticed some resonance to the inner skin too so simply placed some strips to kill that off too. Wasn't going to go too mad!



First observation: Bonnet now closes with a lovely resounding thud. Previously it was something of a clatter!! Dynamat certainly working in that regard. there is also something quite nice about tapping a clad panel. More "steel sheet" than "tin can" Very Happy

Oh and if you're wondering why its black in colour? Its so the blood from your fingers doesn't show. the edges are sharp!!

Step 3: Cut and fit an insulated blanket. Sourced mine (on something of a late night surfing whim!) from evilbay:

http://www.ebay.co.uk/itm/261912839993



Again as it was so warm it was seriously sticky! Careful thought required on cutting and fitting. You only get one chance!

Step 4: Drink tea in midday sun! (Very British!)

So what are the results of the re-test:

Outside (30cm from grill, level with bonnet): 66 dB
Inside (30cm from dash, level with top): 55 dB




Hmmm so hardly much to write home about but I'm convinced (could just be the heat effecting my brain) the sound is "deader". Guess I should have taken it on a run for a proper sound test.

Oh and one last thing. In this heat Dynamat is difficult to remove from its backing. Its sticky enough when cold, once warm its gunky! Had to move to cutting inside the garage Smile

Hope the above is useful to someone.

TTFN

Barney
Post #434820 30th Jun 2015 12:36pm
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
Posts: 20280
United Kingdom 
I find that's there is a dB or two to be gained from each location of fitting, I found these margins similar when I did just the seatboxes.
All of them add up to larger gains.
Yours is already quieter than mine at approx 69 / 70 dB on mine, but there are variables to that and I'm running straight through centre silencer too.
Post #434826 30th Jun 2015 1:03pm
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fathaggis



Member Since: 31 May 2015
Location: taynuilt
Posts: 385
Scotland 
very good write up Thumbs Up giving me ideas on doing my puma bonnet Thumbs Up
Post #434832 30th Jun 2015 1:22pm
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IanW



Member Since: 12 Jun 2011
Location: Gloucestershire
Posts: 172
United Kingdom 2008 Defender 110 Puma 2.4 CSW Zambezi Silver
Sort of on the edge of the topic, but a firm called Faber Acoustical do a free iPhone decibel meter app which works from the iPhone microphone. Very good with a paid for more complex one if needed. Ian One wife - livid
Post #434847 30th Jun 2015 3:52pm
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IanW



Member Since: 12 Jun 2011
Location: Gloucestershire
Posts: 172
United Kingdom 2008 Defender 110 Puma 2.4 CSW Zambezi Silver
Sort of on the edge of the topic, but a firm called Faber Acoustical do a free iPhone decibel meter app which works from the iPhone microphone. Very good with a paid for more complex one if needed. Ian One wife - livid
Post #434848 30th Jun 2015 3:54pm
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IanW



Member Since: 12 Jun 2011
Location: Gloucestershire
Posts: 172
United Kingdom 2008 Defender 110 Puma 2.4 CSW Zambezi Silver
Sorry double post. Ian One wife - livid
Post #434849 30th Jun 2015 3:54pm
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Barney12



Member Since: 09 Jun 2015
Location: South West
Posts: 744
United Kingdom 2014 Defender 90 Puma 2.2 XS CSW Corris Grey
custom90steve wrote:
I find that's there is a dB or two to be gained from each location of fitting, I found these margins similar when I did just the seatboxes.
All of them add up to larger gains.
Yours is already quieter than mine at approx 69 / 70 dB on mine, but there are variables to that and I'm running straight through centre silencer too.


This is what I'm hoping. I'm just in the middle of doing the rear. Hopefully will do the front at the weekend as long as 'The Rascal' doesn't make me do the gardening Big Cry
Post #434956 30th Jun 2015 9:23pm
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Barney12



Member Since: 09 Jun 2015
Location: South West
Posts: 744
United Kingdom 2014 Defender 90 Puma 2.2 XS CSW Corris Grey
IanW wrote:
Sort of on the edge of the topic, but a firm called Faber Acoustical do a free iPhone decibel meter app which works from the iPhone microphone. Very good with a paid for more complex one if needed. Ian


Cheers will take a look.
Post #434957 30th Jun 2015 9:23pm
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YOLO110



Member Since: 14 Feb 2015
Location: Perth Oz and Stansted UK
Posts: 1641
Australia 
Re: Bonnet Insulation - Install with Pictures.
Barney12 wrote:
I had a few hours spare this morning so decided to crack on with my planned bonnet insulation project which is part of a much larger sound insulation project.

...

Hope the above is useful to someone.

TTFN

Barney


VERY USEFUL Barney!!!

Many thanks mate!

Pete. Very Happy YOLO... You Only Live Once...
Post #448956 25th Aug 2015 8:56am
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K9F



Member Since: 12 Nov 2009
Location: Bournemouth
Posts: 9610
United Kingdom 2008 Defender 90 Puma 2.4 XS CSW Stornoway Grey
Hardly seems worth the effort for what appears to be such a minimalistic static sound reduction? Placebo effect may compensate though. If you go through life with your head in the sand....all people will see is an ar5e!!

Treat every day as if it is your last....one day you will be right!!
Post #448964 25th Aug 2015 9:21am
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Lambley



Member Since: 20 Apr 2013
Location: Mid Devon
Posts: 1435
United Kingdom 2006 Defender 90 Td5 HT Java Black
I'm sure that when the sound gets louder due to increase in engine revs then it'll make a bigger difference, one or two db doesn't sound like much but I think it works on some sort of scale, so a few db less can mean half the noise level, something like that anyway, I'm probably talking twaddle as always though.
Cheers for the write up, link and pics, I'm thinking of doing this soon - as well as the interior
Post #448969 25th Aug 2015 9:47am
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K9F



Member Since: 12 Nov 2009
Location: Bournemouth
Posts: 9610
United Kingdom 2008 Defender 90 Puma 2.4 XS CSW Stornoway Grey
Be aware that fitting bonnet insulation can actually increase cab noise apparently. Also the phone applications for noise measuring are only accurate when static.

http://www.defender2.net/forum/topic20069.html?highlight=db If you go through life with your head in the sand....all people will see is an ar5e!!

Treat every day as if it is your last....one day you will be right!!
Post #448975 25th Aug 2015 10:11am
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YOLO110



Member Since: 14 Feb 2015
Location: Perth Oz and Stansted UK
Posts: 1641
Australia 
Maybe I will just wear some noise cancelling headphones then!! Laughing

2 pairs actually! YOLO... You Only Live Once...
Post #448979 25th Aug 2015 10:14am
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roel



Member Since: 08 Aug 2009
Location: Lelystad
Posts: 2039
Netherlands 2003 Defender 90 Td5 PU Caledonian Blue
That's probably cheaper too. Laughing Roel

1984 90 2.5 na Diesel - RR V8 (1994-2001)
1997 Camel Trophy Discovery 300TDI (2001-2009)
2005 G4 Discovery III 4.4 V8 (2008-2018) It's gone but it still hurts.
2003 90 Td5 (2009-now)
Post #449509 26th Aug 2015 7:51pm
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Barney12



Member Since: 09 Jun 2015
Location: South West
Posts: 744
United Kingdom 2014 Defender 90 Puma 2.2 XS CSW Corris Grey
YOLO110 wrote:
Maybe I will just wear some noise cancelling headphones then!! Laughing

2 pairs actually!


and you won't be able to hear the wife! Double win!! Mr. Green
Post #449514 26th Aug 2015 7:59pm
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