Best sound deadening for type 26 with a hard top.

[Elan Peter]

Hello again. I wondered if anybody know where I can get the best, top quality sound deadening for my type 26 (which will have a hard top). My car will have a noisy racing exhaust and even noisier straight cut Gbox. As a result of the above, I thought that investing in some top-notch sounds deadening would be a very sensible idea.
The car will be fully carpeted and have a headlining so we have no problems wit underfloor stuff.
Best regards, P

[baileyman]

If I recall correctly I am building a car similar to the one you are, though I will have helical gears. I am expecting to provide sound deadening at the ears, probably also piping in internet radio.

John

[Elan Peter]

Yes, that is a good idea. I need a more permanent solution as the car will be driven backwards and forwards to hill climbs and there is not a single one nearer than 100 miles away so I need some comfort.
Best regards, p

[rgh0]

I dont think there is much you can do with sound deadening materials for the sound of a straight cut box in an Ealn. Just wear ear plugs and get into top gear as soon as possible on the road. On the track the straight cut box noise means you dont have to look at the Tacho to know when to change up

cheers
Rohan

[Elan Peter]

I just want something that will get rid of as much noise as possible. Just so you can talk without shouting that much
Best regards, P

[rgh0]

I just want something that will get rid of as much noise as possible. Just so you can talk without shouting that much
Best regards, P

Rally style headsets and mikes with noise cancelling help to avoid shouting

cheers
Rohan

[Elan Peter]

Wonderful
I see I'm not going to get very far with this one
I'll just have to speak to a specialist.
Best regards, P
P.S. Very "interesting" suggestions though

[Elanman68]

Modern sound deadening carries a weight penalty which seems at odds with your intent to use the car for competition and the efforts you are going to make to replace heavy components with lighter versions as per the 26R specification?

I can see the benefit in a road car and have recently fitted a fair amount of Dodo Mat https://www.dodomat.com/ in my S4 FHC, other products are available such as Dynamat https://automotive.dynamateurope.com/ . These all work on the basis of deadening panels to reduce resonance and then a sound absorbing layer on top. The deadening materiel is dense (8.7kg for a roll which covers 3.5m2). Regardless of the way the car is to be used I would not put this type of materiel into the hard top as it's weight high up in the car.

The foams used for sound absorption are much lighter but it all adds up. The advantage of the modern closed cell foams is that they don't absorb water in the way the more traditional felt based materials do.

After a lengthy round trip to Hethel last Sep with no sound deadening, just carpet, my ears were ringing, the trip to Le Mans last month was altogether quieter, I could even hear the radio!

Hope that helps, previous suggestions seem reasonable and valid for a competition orientated car to me.

[wotsisname]

Dynamat comes in a few thicknesses and therefore weights. I have it above the headlining of my +2 and in various other places under the usual horsehair type stuff.. Too early to say how much it will reduce the noise.. but the boxes did weigh quite a bit.. I'm planning to use my car for road trips, hopefully in the bits of
Europe we are probably divorcing... so noise reduction was more important than weight increase (within reason) ... A pair of ear plugs is not going to weigh more than a few grams and the money saved would be a lot of petrol... of course you could go all out with some earbuds and listen to Fleetwood Mac on your way to the track
regards
Adrian

[Elan Peter]

Thank you Elan Man. That is very helpful. I am not overly concerned at the overall weight of the car as it will mainly be used on the road. I would therefore say that the suggestions you have made are ideal.
The class I will be hill climbing in is set for race cars for the road and therefore they are comfortable and quick, my car will be much lighter than these even with all of the mods on. I think the lightest car in the championship is 700kg, I reckon with the lighter new body shell that I have I can get somewhere below that mark (it is a very strong lightweight shell and does not flex but it is much lighter than the old one).
Best regards, p

[Elan Peter]

Hello Adrian. Your suggestions are great apart from one thing, I'm more of a Beatles man myself (unless it's the chain, which is perfect racing music).
I will look into Dynamat.
Best regards, P

[Elanman68]

Peter, you're welcome. If, as it seems, weight isn't a concern, then in my view it's a good option.

[Elan Peter]

Like you say, it looks good. Very expensive but if it does the job, then it's worth it.
Best regards, P

[mikealdren]

Different materials work for different sources of noise. As a starter for 10:

Noise barriers stop noise transmission, e.g. bulkheads and wheel arches. Weight is good here, felt and rubber/metal/tar based materials. Any gaps in the material allow sound transfer so attention to detail is critical. any air gaps can transmit enormous amounts of noise including wind noise, block them off.

Anti drumming materials damp panels and stop resonances, e.g. door skins and bonnet panels. Exact coverage is not so critical but positioning on the panel can have big effects.

Absorption materials take noise out of a volume e.g. the cockpit, typically softer materials like felt and trim.

Felt and carpet can act as barriers, anti drumming and absorption

You really need a mixture, depending on what noise you re attacking.

[Elan Peter]

Wow, I hadn't realised how much work was needed to sound proof a car.
That is very kind of you to take the time to tell me, I thought it was just a Slap-It-On approach that people went for.
Best regards, P