Sound deadening or not?

Hi,
i am at the stage where i have started the paneling of the chassis.
What are the experience from the people out there that have finished builds, does deadening the cockpit do any good, or is it wasted weight since the engine will be so loud anyway?
Will coat the wheelarches with rubber on the inside to protect the glasfibre and get rid of the gravel noise, but should i put any effort at all in sound in the cockpit?
Doesn't feel right to add 15+kg to the car...
 

Clayton

Supporter
Hi Daniel
I added Dynamat to all panels around the cabin and 25mm/1” convoluted foam between them.
Would do it again in a heartbeat, ever try and squeeze in more.
Added a thicker bulkhead window as well, 6mm to 10mm.
Has really paid off for noise and heat reduction.

Clayton
 
Hi Daniel,
It depends what you want out of the finished car. If you want a raw seat-of-pants racer, then no sound proofing, however if you want it for long distance cruising, taking the wife out then add it to the build. 15kg isn’t excessive when the car will weight around 1000kg and the additional weight can be saved elsewhere (Li-Iron battery, alloy heads etc.)
Alternatively, anti-noise headphone sets work really well!
Regards,
Andy
 

Simon

Supporter
People questioned me when I fully lined my Cobra cabin…”in an open car?, why bother” but the difference is profound. Less general mechanical noise means far more enjoyment of the exhaust sounds. Same when I lined my GT40 cabin. Just improves the general “feel” and “quality” of the car. All depends if it’s a race car or you want to use it on the street in the real world….
JMHO
Simon
 

Jim Craik

Lifetime Supporter
P/2264 is a street car, I used Dynamat for noise and bubble insulation on the firewall under the carpet, much cooler and quieter. Also a thick plexy firewall window really made a difference.
 
I have a 10mm bulkhead insulated with a fire resistand, noise dampening wool (fibre) sort mat called Akotherm sandwitched between the two alloy panels.

On the engine side there's also heat barriers added, on the cabin side i used the Russian Dynamat, STP Aero Bomb.

Tunnel and front firewall is heat isolated with Thermoglass, as is the whole rearclip. As the front firewall is also 10mm there's Akotherm mats sandwiched between.
The whole floor is covered with the Russian Dynamat, STP Aero Bomb.
 

Dwight

RCR GT 40 Gulf Livery 347 Eight Stack injection
Supporter
JP is the Russian Dynomat sold in the U.S. under the name of KillMat?
If so I have used it in a couple of car with great results. I buy the 80 mil for a fourth of the cost of 50 mil Dyno Mat.
 
good replies.
I think i'll get atleast dynamat superlite one layer surrounding the cabin, then isolation to the firewall for heattransfer.
Pipes in tunnel will be isolated with advanced material already, so not expecting much of a heattransfer from there.
 

Ian Anderson

Lifetime Supporter
Supporter
good replies.
I think i'll get atleast dynamat superlite one layer surrounding the cabin, then isolation to the firewall for heattransfer.
Pipes in tunnel will be isolated with advanced material already, so not expecting much of a heattransfer from there.
i am not sure how your radiator outlet air is ducted. In my GT40 it has half depth nostrils and normal driving it is fine, but get stuck in traffic with fans running and the hot air hits the front of the tub near pedal box and the heat build up is quite notable. And feet get really sweaty. So perhaps heat mat for there too.

ian
 
i am not sure how your radiator outlet air is ducted. In my GT40 it has half depth nostrils and normal driving it is fine, but get stuck in traffic with fans running and the hot air hits the front of the tub near pedal box and the heat build up is quite notable. And feet get really sweaty. So perhaps heat mat for there too.

ian
I have modified the bonnet to accept full depth of the radiator shroud, so all of the hot air will go out above the bonnet.
Sure heat will still radiate from the aluminium sheets etc. So maybe some form of insulation is needed towards the front too.
 

Neil

Supporter
Is the insulation you are considering installing flammable? I would take that into consideration.
 

Howard Jones

Supporter
"I have modified the bonnet to accept full depth of the radiator shroud, so all of the hot air will go out above the bonnet.
Sure heat will still radiate from the aluminium sheets etc. So maybe some form of insulation is needed towards the front too."

If all the radiator exhaust heat is being ducted out of the body then insulate the exterior of the duct to keep the heat inside the duct. I would use an adhesive-backed fiberglass mat with aluminum backing.

Here's an example:

 
Thanks all for the great replies.
I have decided to implement Dynamat superlite in one layer around the cockpit, and then a thin isolatating foam mat for the tunnel, rear bulkhead, and front bulkhead.
I will probably be using the golden heatshield you linked in there Howard, seems appropriate in some areas around the engine.
 
Hi Daniel, I ran for years with no insulation and noise-cancelling headphones. After years of being roasted, on the 2016 rebuild, I padded the bulkhead and driver's seat to reduce heat, but fitting the aircon was the best solution ! I also fitted silencers for the first time. After that, the greatest noise reduction I achieved was sound-deading mat on the floor and front wheel inner walls.
It was amazing how much noise came up from the road and from the front wheels. Not bothered about the weight any more, Tony.
 
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