HAVING recently acquired an ex-military 1989 Land Rover 110 6x6 Perentie, we’d been looking out for a sound-and-heat dampening option to help moderate the rig’s in-cabin comfort from an ‘agricultural standard’, to something closer to the mainstream.
While the heat radiating off the engine and exhaust was causing some discomfort in the cabin, particularly for the co-pilot as the exhaust pipe goes straight from the manifold directly under the passenger’s seat, the main problem was the noise. We all expect our 30-year-old rigs to expose us to a bit of road and engine racket, but we’d measured 85dB in the Landy’s cabin at 80km/h on the bitumen.
Meanwhile, online forums for these ex-military vehicles claimed that some owners had recorded an ear-shattering 90 to 100dB due to a combination of panel vibrations, engine and road noise. It’s obvious the sticker on the driver’s visor warning of potential hearing damage over 80km/h isn’t exaggerated.
We’d seen a Land Rover enthusiast use Dynamat to sound-dampen their rig, so we headed straight for the Dynamat Xtreme, a thin, super sticky butyl rubber bonded to an aluminium alloy skin. The rubber and heavy aluminium can mould around interior surfaces, adhere to a surface and stay in place without any surface prep, and without tearing. Even better, there’s no nasty odour to leave you gagging after installation.
Produced in sheets, it’s simple to cut and install and leaves no sticky residue or similar mess to clean up. Indeed, it wasn’t the installation that took time, it was removing the seats, rear wall and door panelling. While we’d aimed to install Dynamat on the underside of the roof, the 30-year-old plastic sheath that lines the cabin’s ceiling looked like it mightn’t make it through the process intact, so we’ve left it alone for the moment.
The Perentie 6x6 is wider in the hips than a normal 4x4 Land Rover – allowing for three seats across – and it’s tall with heaps of headroom, so the job took two boxes of Dynamat at 3.3m² a box. It was definitely worth it, though. It’s now possible to hold a conversation in the cabin at 80km/h without raising our voices.
With a sound-metering app, the new reading was 71dB at 80km/h and 63dB at idle. And if you consider where we plan to take the rig, the modification makes a lot of sense for comfort and safety. Our aim is to reduce the inevitable fatigue that comes from rattling around in a rig with our ears bursting.
I don’t know about you, but it’s money well spent considering we bought the old girl for treks along tracks like the 1850km Canning Stock Route (plus the 4500km to get to Halls Creek).
Distances like that with large amounts of cabin noise could result in hearing loss just like the sticker says. Most occupational/industrial noise regulations agree that noise becomes hazardous when it exceeds 85dB Decibel for an eight-hour exposure.
4x4 Upgrades and gear reviewed on 4x4 Gear
Available from: audiotech.net.au
RRP: $299 (3.3m²)
We Say: Worth its weight in hearing protection.