Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Dynamat Noise Suppression

Over the winter, I'm considering fitting Dynamat to the panels of my Plus 4 to try to reduce the road and engine noise. I'm curious to learn how effective it is likely to be, how much is required for one car and whether its best to buy sheets or rolls? It's not cheap so I'm trying not do do my usual trick of buying far too much and then watching the excess slowly deteriorate over the years!

Somewhere on here is a thread of Peter Jenks doing that to his Roadster a while ago. Maybe a PM to hit would get an answer.

Yes PeterJ Dynomatted his Roadster in about 2014

The thread should be still on here but might take a bit of searching

I’ve put Dynomat behind my subwoofer in the passenger footwell, behind my speakers and on the floor on both front footwells

It was just to get a bit more clarity from the sound system and to help prevent a few unwanted frequencies

Didn’t test it without as I put it in with the new system so hard to know the difference but I feel better for doing it

Just looked at the posts on Dynamatting, very interesting. It looks like 4 sheets will do a M3W. If I start with that then I can always buy more sheets!

I've lined the floormats of my Aero (rather than sticking the mat to the tub): it works - there's definitely less road noise coming up through the floor.

You might also consider the lightweight dynamat - which is said to give most of the sound reduction without the full weight. I've used the lightweight in the doors of my i8 (which open upwards on a gas strut, so weight matters) and it's again made a difference

Will

Keen to follow this, and I hope the OP will share progress and results.

My first Lotus was a 2009 Elise, which I was able to purchase new. Although I'd had sports cars in the past, my direct transition to the Lotus was from a "luxury" SUV, where the engine was approximately 3 km away, so to have the engine about 12 inches behind my ear. separated only by a thin sheet of glassfibre below, and a thin sheet of clear glass above, was quite a change. Being new, the issue wasn't rattles, but simply loudness and droning.

I removed every part of the inside, and placed foam insulation blocks in some areas, and Dynamat everywhere I could: floors, inside doors, especially on the rear bulkhead (engine i back, so front bulkhead not much of an issue, but as the dash was mostly out, did what I could back there too). The Lotus featured acres of very had plastic, and plain painted metal, mostly aluminium, so I also covered all of these plastic parts with leather (had this done by the Lotus Trim Shop, which no longer exists, I believe). Previous to this, it was not possible to have much conversation, or hear the radio at all, and post this, conversation and music became possible, the car was just overall quieter, could hear the stereo, and droning substantially reduced. This had been a car that, if you planned to drive more than an hour, you really needed to wear earplugs.

I don't expect this kind of result with my recently acquired '64 Plus 4, given it's age and construction type versus a modern car, even a Lotus, but I can't imagine there wouldn't be some improvement. My hesitation has been that once stuck, Dynamat - and similar products - are quite difficult to unstick. The Lotus was mostly a one-piece tub, whereas the Morgan is many (many) separate parts, which will likely need removing at some point. I've thought about starting with just a layer of their very heavy padding, which doesn't require adhesive. Don't know if anyone else has tried this.

I guess it all depends on how often you drive with the roof up which is where you see the most effect, in my case that would be so negligible of my drive time just not worth it. My M3W does not have any Dynamatting and when I was in one that was fully Dynamatted I couldn't really tell any significant difference.

Peter J here..
Yes, I applied the thin (5mm?) Dynamat to the interior of the Roadster, including the doors, floor, rear bulkhead and the transmission tunnel. It made a significant difference to road noise and a little unexpectedly, it massively reduced heat transfer into the footwells.
I have an info sheet, based on an article in Miscellany. Pop me a PM with your e-mail and I'll send it on to you.

It took me about 4 days in total, spread over a few weeks. The seats came out and I made angled spacers, as reported by others, they allow the seat adjusters to work properly.

So, have I applied Dynamat to th Aero S4 Chassis on the Plus 8?
No, the car is already much quieter than the Roadster and there is no heat sink into the cockpit.
BUT on the basis that you cannot have too little NVH it is on the list of "Things to do".

I have tried this with silent coat which seems to be the same product as dynamat. I used self adhesive 5mm foam backed sheet under the carpets in the foot wells and the silent coat on the door panels and the exterior panels to the foot wells in the engine bay. My aim was to eliminate the drone at 2500rpm that was quite annoying, I would say that it worked to 60% and actually makes the car sound a little better with a more defined exhaust note which I like.
One of the spin off benefits was to make the doors sound rather well made, giving them a satisfying clump when closing.I carried this out in the autumn and so cannot comment on whether the aluminium coating on the silent coat will arrest some of the excess heat coming in from the engine bay, I think it will.
One of the observations I made along the way is that not much material is needed as the door interiors take several small sheets rather than a complete coverage, this due to the restricted access . The engine bay the same and the boffins among you will know that the vibrations of a sheet of metal can be deadened by judicial placement of a relatively small amount of sound deadening product.
So in conclusion, not the most dramatic result from a few hours work but quite satisfying and in my opinion worth the effort.

I use earplugs when driving motorways.
I believe most of the noise comes from the wind in my Morgan.
How much increase in weight from the Dynamat? I plan to loose weight myself to improve performance of my Morgan🙈
And I will never install a radio in my Morgan, I enjoy the exhaust sound, the birds singing 🙂🐤