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Discussion Starter · #1 ·
Well, I’m done with my MK4 gocart. Sound deadening material will marginally decrease the room in the foot box (and other areas) and I need every fraction on an inch achievable. My thought that the Cobra is the last of the LOUD, SCAREY, OPEN AIR, HAIRY-CHESTED DEATH MACHINES, so what I’m I sound deadening against? I’m definitely going to use thermo sheets in the engine compartment for the foot boxes. But Really, is the rest really necessary???
 

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I understand that it gives the car a more solid, less tinny feel. I'm sure carpet helps a bit too. i used kilmat, which is less than 1/8" thick when rolled on. If you can't spare an extra 1/8", then I suspect you'll need to find other modifications to make the cockpit fit your frame. At the end of the day, it's your build and you can do what you want. Might be easier to do it now rather than after the car is completed and you change your mind.
 

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Yes, it is. There are certain sounds you kinda want to hear. But a lot of sounds you don't. A good sound deadener will eliminate a lot of unwanted noise. You'll appreciate it.

I recommend Lizard Skin. Much easier to apply, works really well, and doesn't take up much space at all.
 

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You're correct sound deadening doesn't do much. I've never used it in any of my builds, no regrets, nothing "tinny" at all. Some heat shielding in the foot boxes does help though.
 

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Well, I’m done with my MK4 gocart. Sound deadening material will marginally decrease the room in the foot box (and other areas) and I need every fraction on an inch achievable. My thought that the Cobra is the last of the LOUD, SCAREY, OPEN AIR, HAIRY-CHESTED DEATH MACHINES, so what I’m I sound deadening against? I’m definitely going to use thermo sheets in the engine compartment for the foot boxes. But Really, is the rest really necessary???
I put dynamat on all of the inside panels it really helps with the heat and noise.
 

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Just my personal opinion, but yes it does make a difference. Does it make the car quieter? No. What it does is take away all of that ting noise from road pebbles hitting the bottom on the car.
 

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On my first Cobra I installed sound deadener and carpet. Gave the car a finished look and feel. On this build, I went with raw all-race look.







 
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My dad drove his cobra in gelcoat the first summer and had no carpet, only seats.
It was like riding in a big tin can, you could hear stones bouncing off the bottom of the floor. He had a wrench in the trunk and we had to stop and I had to hold it in my lap because the bouncing around was too annoying.
He had a local upholstery shop put in the carpet and they basically refused to not put sound deadener in it.
 
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Discussion Starter · #10 ·
OK...I’ve been convinced that it’s a good addition to the build. I’m going with the 50 mil Kilmat. How many sq ft do I need to do the cockpit and trunk?
 

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OK...I’ve been convinced that it’s a good addition to the build. I’m going with the 50 mil Kilmat. How many sq ft do I need to do the cockpit and trunk?
Get 2 boxes. Only 1 if you’re not doing the trunk
 

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I have to follow all the SCCA rules, so I used four coats of Lizardskin. Two heat and two sound, per the manufacturer recommendations. It's expensive and difficult to apply properly, but it's definitely worth it. Highly recommend. I also riveted on a piece of very high temp heat shield to the engine side of the driver footbox, which really helped a lot because it was getting so hot that it burned the paint off the inside next to my feet!
 

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Everyone building these cars is shaped a little different. So it might be your elbow or my knee which finds an uncomfortable place to come to rest. So it is an adventure to find all of those critical tight spots while you are building the thing. I used posts an opinions from tens of different builders on on ffcars and Factoryfive to determine the ones that would affect me. So I concluded there was not enough room at 2 spots that had to be fixed. One was the vertical crash post next to the left foot area and the aluminum panel just behind that post which touched the outside of my left foot right behind the toes. So I did a small modification to push out the panel just in that small area about 6x12 inches. I called it my mini mod. I also moved the crash post from on top of the horizontal foot box crash bar to a bracket that I welded about 2 inches forward of the original location. This involved replacing the outside and one upper aluminum panel. what it did was let me relax my foot forward and off to the left side for a comfortable driving position. Also, it gave me room for a “dead pedal”. So it took more space resulting in the moving of the crash bar. This also freed up space for extra layers of deadening material. I used carpet, mat insulation, rubber deadening mat, and the “Dynamat” material. I can honestly say that when I get in the car, it is more like putting it on like a jacket and trousers. It doesn’t fit anyone else but me. Oh. Also, I moved the accelerator pedal left a little to clear the material and adjusted the race pedal pads to the far left position. This spaced the pedals for my wide feet. So a combination of things made me go to the tedious modifications I did in this area. But the benefits of this work never goes away. You feel the difference every time you get in. The sound damping and heat reduction is so worth it as well. In this case, it was one of those ”killing two birds with one stone” sort of thing to get the desired result. Good luck. WEK
 
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