Lotus Europa Community
Lotus Europa Forums => Technical Articles and DIY tools and tips => Topic started by: dave3b on Monday,March 15, 2021, 06:17:40 AM
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I have 1974 TCS. The bulkhead between the front of the engine and drivers compartment has a thick brown Matt with a 18 ga aluminum on top. I presume its acting as sound proofing and heat shield. Any suggestions on replacing this with something a bit more efficient.
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https://automotive.dynamateurope.com/
Not sure where you are but Dynamat is pretty good stuff and they have a range of materials for different areas/applications. Have seen it used on Land Rovers and it made quite a difference.
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The thick brown matt is probably the original engine side firewall insulation. The aluminum sheet must have been added a PO. My hunch is it may actually be making the noise situation worse by providing a smooth flat surface to reflect sound and by resonating. Dynamat is useful when applied to surfaces that vibrate, or resonate. In a car made of sheet metal, almost every surface tends to resonate, so butyl rubber (Dynamat) makes a big difference to the noise inside. The structural part of the firewall in a Europa is made from low density fiberboard (or LDF). LDF is essentially incapable of resonating, so a layer of butyl on the firewall probably won't do much good. On the other hand that sheet of aluminum that the PO installed on the firewall probably will resonate beautifully. If you remove the aluminum sheet, then I think you want a sound absorbing material, rather than a vibration damping material.
I like the look of this sort of thing for the engine facing side
https://www.designengineering.com/floor-tunnel-shield-ii-21-x-48/
or this if it wasn't so expensive
https://www.designengineering.com/stainless-steel-acoustical-floor-tunnel-shield-22-x-19/
The only problem with those is the fiberglass insulation is a bit thin, so a bit of extra insulation underneath would be a good idea, I reckon.
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If you have an S2 or TC/S, then by all means, use dynamat (or equivalent). Make sure anything you use inside the engine compartment is rated for that use due to the risk of engine fires.
On an S1 the massive curved sections leading to the hollow sills act like two giant flugelhorns. The chassis is riveted solid to the body. Noise is just part of the package.
I lined both sides of my S1's firewall with a dynamat equivalent and fit a sheet of aluminium as well.The rest of the interior was also lined with sound deadening. It's unbelievably, laugh-out-loud, LOUD. It's actually kind of cool for an hour. After that, not so much. I use Bose aviation, noise-cancelling headsets and a comm system for any trips.