The Lotus Grand Tourers

Hi All

I have pulled out the interior of the car , seats, carpet, under carpet soundproofing, etc.

I noticed from the photos, some of you have installed dynamat or a similar product as the first layer over the whole interior of the car.

My question is.
When it was all put back together , carpet, seats, etc, is it quieter than the original soundproofing?

I used a lightweight version(1/3 weight of standard dynamat). It isnt as quiet as the mass loaded vinyl but it weighs a fraction of the original material. If you want better sound deadening go for the standard version, you can add miltiple layers on top in certain areas as well.
Being made of butyl it also has the added benefit that if your carpet gets wet it doesnt hold the water for the next 6 months

I didn't notice any difference using dynamat on my floors...... door shells may be different though (KevW on here did that - he may pipe in soon with a thumbs up or down).

TBH dynamat type stuff is to stop drumming on steel panels and doesn't have much effect on fibreglass. Foam, jute or lead/foam sandwich is best for airborne sound.

Simpatico wrote:I didn't notice any difference using dynamat on my floors...... door shells may be different though (KevW on here did that - he may pipe in soon with a thumbs up or down).

TBH dynamat type stuff is to stop drumming on steel panels and doesn't have much effect on fibreglass. Foam, jute or lead/foam sandwich is best for airborne sound.

Agreed - dynamat on its own isn't a noise barrier, but does dampen drumming. As fibreglass will typically resonate at a lower frequency than steel, it's use may be more limited than on steel; I've lined my floors and transmission tunnel with a similar product and plan also to do the boot area as there is quite a lot of drumming from the exhaust there.

From what I've been able to find out, a layer of mass loaded vinyl (5mm thick) with a backing sheet of 1cm thick open cell foam may be best as a sound barrier. I used closed cell foam on my car which I've recently found out is not much use as a sound absorbent material, although it doesn't hold water. You can't have it all it seems!

I think the original Lotus material was a thinnish vinyl mat backed with padding of some description.

ATB Richard

I copied Shaun W and covered the doors on my previous Excel with Silent Coat which is similar to Dynamat.
http://lotusexcel.net/phpbb/viewtopic.p ... oat#p36607

I'm running my current car with just some thin closed cell foam sheet cut from a camping mat laid loose under the footwell mats. I ripped out the water absorbent factory fitted sponge stuff when it got wet. I can honestly say I really don't miss the O.E. footwell soundproofing at all.

I agree that stuff like Dynamat seems to be best suited to steel bodied cars.

Hi if you decide to go the dynamat route please PM me, I have an unopened box of the stuff which I bought for an Elan resto (decided not to use it on the Elan). I'm in Sydney. R