109 Soundproofing

The 109’s interior noise has been well reduced by the Wright Off Road matting system ever since the build, but with the Tdi engine and overdrive, noise levels are still an issue.  Maybe I have become used to the levels in Helena’s 90XS and previously the Range Rover, maybe I’m just getting old, but with the prospect of a change of jobs that would have involved double the commuting distance, it was time to improve matters.

109-soundproofing-(2) The bulk of the noise seemed to be coming from around the bell housing and transmission tunnel.  I started by adding 2″ open cell medium density foam under the transmission tunnel and the bell housing arch of the bulkhead.  Some of this was a little tight – the aft position of the engine and gear box means there is little space between the starter motor bulge of the bell housing and the cover panel.  As strip of thinner foam sheet was added over the top of the arch as there seemed to be a small void between the arch and the WOR mat.  For this I used yoga mat, a little like camping roll mat but thicker and slightly softer.  More of this yoga mat was used to line the foot well floors under the WOR matting and the foot well tops.

109-soundproofing-(1)109-soundproofing-(4)The 2″ foam was then applied under the seat base, from fuel tank to fuel tank with a few cut-outs to clear the hand brake lever, fuel taps and various gear levers.  The foam is going to absorb water, but open cell foam is much more effective at noise reduction than closed cell foam and it will also drain down and dry out quickly  as it is sitting high up above heat sources (well away from the exhaust) and out of any water traps.  With the chassis and bulkhead being galvanised, the fuel tanks red leaded and everything having copious amounts of Schutz, plus the fact that I hardly ever wade the vehicle, corrosion shouldn’t be a problem, but I will keep an eye on things.  This is not dissimilar to how LR soundproof the vehicles in the factory – the matting under the carpets and inside the engine bay of my RR have open cet foam, and the transmission tunnel on Defenders has thick open cell foam bonded to its underside.   The inside of the gaiters were packed with thinner foam sheet to allow flexibility but to trap noise before it reaches the gaiter.  I also added a cut down Defender gaiter in place of the leatherette Discovery gear stick gaiter, which was shedding its black plastic outer coat and had minimal noise reduction qualities, and added the smaller transfer box lever gaiter tot he base of the overdrive lever to tidy things up a little.

109-soundproofing-(3)A quick test on the driveway to make sure the transfer box gears are re-engaged before I leave for work at 4AM tomorrow, bleary eyed,  suggests the drive should be a fair bit quieter.  It remains to be seen whether some vibration or rubbing will be transmitted by the tighter packed foam around the bell housing.


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  1. Hi Nick:

    I bought some years ago the Wright Off Road acoustic mat. It is still in the box as work comitments left the Land Rover Santana in the garage for more than four years. Now I am on the way to finist it, but befor installing the mat I will have to change the seals of my Santana Overdrive and install it.

    As I like to read in internet about clasic Land Rovers I found this :


    It is the first really bad opnion about the mat I have found. My 88 2.25 diesel is really a noisy vehicle and I really want to make it more comfortable.

    It would be nice to see all photos bigger. Now only the first one can be seen

    Regards form Spain

  2. Hmm. There seems to be a glitch that is only allowing the first photo on each post to be expanded, even though all photos in each post are uploaded together and identically. I’ll have to look into it.

  3. Hi Nick,

    I’ve followed a lot of the great stuff you have done over the years. I too am now looking at the Wright off road acoustic matt system for my Lightweight. I know that it wont be a perfect fit and that I will need to cut it. I was hoping to see a few more of your pictures up close to get a better idea of what the finish will look like once cut. I like the idea that you cut your foot well and gearbox tunnel mat into three sections, I am looking to do the same firstly to allow me a chance of getting it to fit and secondly so that I can gain access to the gear box tunnel more easily for oil checks and top ups. Are you able to share some close up pictures of the cuts you made to your acoustic matting, would very much appreciate it before I spend a lot of money on a matt that I may never get to fit.

  4. Hi Steve,

    The cuts were a rushed affair with a Stanley knife while fixing the loose reverse inhibit flap stop bolt on the gear box.

    I’m sure it would be possible to modify the kit to fit a Lightweight, but it’d take a lot of work. The bulkhead section would fit behind the heater after cutting the pipe and bolt holes, but that’s the easy bit. The seat base section would need the corners cutting to allow for the Lightweight base’s vertical sides and front, and would need trimming along the bottom edged for the new height, and you’d need to cut a section out of the middle to suit the narrower base (middle would be easiest to hide the cut and joint under a cubby and behind the tunnel flange). The floor and tunnel section would need the ends trimmed off as it would be significantly too long and would need trimming around the door pillars. It might also need the foot well sections narrowing. It’d certainly need the back of the tunnel, where the flange starts, trimming to suit the vertical rather than sloped seat base.

    All in all, I don’t think you’d get a very neat result without sticking and filling the joints with grey Tiger Seal and then spraying it with the same shade of grey PU paint (Drew has the RAL code).

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