Sound insulation on GT 40

Question about noise. Anybody changed the rear glass to thicker sound proof glass? what about more insulation behind the seats to block out more heat and noise. I agree with the too loud your too old idea but i dont want it so loud i have to use ear plugs to protect my hearing. Your guysezz opinion awaiting
 
Too quite!!! dont get me wrong i like the sound of potato potato potato im just asking you guys who have likely riden in Cobras, Daytona coupes etc... how does it compare noise wise to those?
 

Rob Klein

Supporter
after putting a lot of miles on these cars you need people to hear you. These cars on the road are almost impossible for someone in a SUV to see you. I would just get a nice pair of headsets.

have you ever seen a gt40 parked next to a cobra, the GT 40 even looks small next to a cobra.
 

Mike Pass

Supporter
Engine noise unsurprisingly mainly comes through the bulkhead. The nearer cylinders are louder than the ones further back - this effect is more noticeable with Webers where you can hear the front cylinders chuffing. I would insulate the bulkhead for heat and noise as much as you can.
I find that general road noise is transmitted through the frame and then the flat panels. Rear tyre noise is not really an issue but front tyre road noise gets into the cabin via the footwell panels. I would insulate the footwell panels in the gap between inner and outer panels and apply sound deadening in the footwell surfaces. Road noise is not nice noise and is wearing. Engine noise is music if kept to reasonable levels. Exhaust noise sounds better than intake noise especially with Webers as the nearer ones are louder than the ones further back and sound more like a lower number of cylinders.Keep the noise down to reasonable levels and reduce the "bad" noise more than the "good" noise.
Cheers
Mike
 
awe sooooo. That makes sense.Im guessing that something like a stick on tar sound deadning or Lizard skin would be the best bet--would you agree? Cant use anything very thick im thinking keep it around 1/8 inch thick
 

Ian Anderson

Lifetime Supporter
Use as many different layers and materials that you can
each layer will reduce a certain frequency, so for example
Bitumin sound deadner smith metal sheet 2 layers
Board to hold carpet one layer
Carpet one layer

Will be a lot different to a single layer.

Add heat reflector in the engine side of the firewall…stop it coming through to the cabin

Heat proof the front of the pedal box on radiator side…again keeping heat out as an amazing amount can get through and cook your feet and again a couple of layers will reduce noise.

Would be my suggestion and I did 16000 road miles in mine and the noise can get wearing and conversations were at shout level

Ian
 

Jim Dewar

Supporter
I covered all interior metal paneling with Dynamat and Dynapad, even lined the interior of doors with Dynamat ( doors closing sounds like a heavy door. I believe the firewall yields the most benefit, heat and sound. Very comfortable on long trips and you can carryon conversations with occasional passengers
 

Brian Magee

Supporter
I have a double glazed rear cockpit window. I made up the frame and took it to a local window company. I don't know how well it works as I fitted it before I ever drove the car but I am sure it must help a bit.
Brian.
 
I have a double glazed rear cockpit window. I made up the frame and took it to a local window company. I don't know how well it works as I fitted it before I ever drove the car but I am sure it must help a bit.
Brian.
How thick was the glass you had fitted? I imagine glass reflects the heat and sound better than plexiglass?
 

Dave Hood

Lifetime Supporter
Dennis Olthoff sells a thicker rear window for Superformance cars. Not sure if it would fit others. It reduces noise and heat a bit. He also sells a pad that fits behind the seats. That improves the driving position and also cuts down the heat somewhat. I have both installed in my car and they do make a difference.
 
I covered all interior metal paneling with Dynamat and Dynapad, even lined the interior of doors with Dynamat ( doors closing sounds like a heavy door. I believe the firewall yields the most benefit, heat and sound. Very comfortable on long trips and you can carryon conversations with occasional passengers

Done pretty much the same as Jim, but used 25mm thick high rise plumbing insulation instead of dynapad.
Added cork tiles to the centre tunnel to help with water pipe heat.
Upgraded the bulkhead window from 6mm to 10mm laminated glass. Easily carry out a conversation.
Starts at post #81 https://www.gt40s.com/threads/roaring-forties-66.44234/page-5#post-453653

Clayton
 

Kevin Box

Supporter
Good thread going here
I'm curious about the best method of securing the bulkhead to the spider to reduce as much noise as possible.

Cheers KB
 
I covered all interior metal paneling with Dynamat and Dynapad, even lined the interior of doors with Dynamat ( doors closing sounds like a heavy door. I believe the firewall yields the most benefit, heat and sound. Very comfortable on long trips and you can carryon conversations with occasional passengers
 
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