sound deadening

[xrtim]

hi
RS body is due in a few months, has anyone had decent results with sound deadening/insulating the interior of the Ultima, now's the time if I'm going to do it. Dynamat Superlite is the product that I've been looking at, any info welcomed.
Regards Tim

[TR3B]

xrtim said:

hi
RS body is due in a few months, has anyone had decent results with sound deadening/insulating the interior of the Ultima, now's the time if I'm going to do it. Dynamat Superlite is the product that I've been looking at, any info welcomed.
Regards Tim

I started out planning to sound deaden my RS but then it occurred to me a) I'm not building a Cadillac and b) I'm just unnecessarily adding a bunch of weight. That stuff is heavy and it adds up quick. What I chose to do instead was place tactically placed pieces on the flat panels like under the seats, between the floor pan aluminum sheets (to stop the panels from ringing when road debris hits them) and behind the side panels. Just tap any flat panel with your knuckle and if it resonates, put a few tactical pieces on the back and problem solved. In my opinion completely covering everything in Dynamat is overkill. IDK what engine and exhaust you chose but I wear earplugs in mine and that's just the right amount of sound deadening.

If you wanna stay cool definitely opt for the helicopter vents and A/C.

Edited by TR3B on Friday 24th May 07:00

[GTR-P]

Try this hand book on aircraft sound proofing.

https://www.aircraftspruce.ca/catalog/pdf/howtosou...

Aircraft spruce has a variety of light weight sound control products. The hand book contain handy info on how to stop noise from entering the cabin. (Seal all small holes between the cabin and noise. The holes act as small speakers)

[xrtim]

Thanks for the information, engine is 4.8l twin turbo ls, steel block, mufflers are Borla on home built exhaust, hadn’t considered cabin heat, I imagine that most of the heat and noise is at the rear bulkhead from the engine. I’ve gone round tapping panels and they all have a bit of a drum to them, worst are the metal seat wells, I suppose by using Dynamat on the interior it will provide some thermal insulation with the downside being a weight penalty. Maybe some acoustic foam on top of the Dynomat for the floor and thicker between the roll bar on the rear bulkhead is the way to go, planning on doing some trips to Europe so comfort is more of a priority than weight for me.
Regards Tim

[Festa_94]

I’ve done mine, likes been said I know it’s never going to be refined place but I wanted to make it as nice as I could. I’ve done the floor and cabin sides with Dynamat and thermal insulation. Carpeted the cabin too.

[xrtim]

Festa_94 said:

I’ve done mine, likes been said I know it’s never going to be refined place but I wanted to make it as nice as I could. I’ve done the floor and cabin sides with Dynamat and thermal insulation. Carpeted the cabin too.

Do you think it has reduced the noise and vibration in the cabin?
What thermal insulation did you use? And has it improved the heat transfer?

Interested to hear if it’s worth doing or if I’m wasting my time.
Thanks for the reply
Tim

[Festa_94]

Mines still in build stage. I think it will make a difference. I’ve used foiled backed foam insulation that’s also fire retardant

[GTR-P]

There was an idea that was floated a while back to fill the tubes with expandable rigid foam. I always though that this may be helpful in dampening noise transmitted by the frame as well as offering some rigidity to the chassis as used by some car companies (I.e. Nissan GTR). One person thought that in a fire, the material could expand and create a pressure hazard in the tubes but I don't think so because Maths. In any case, there is "fire stop" rated expandable rigid foam available.

[ROWDYRENAULT]

I advocate for the SEM product. Ultra-rigid foam is inserted between two panels, for example, in the firewall behind the seats or the floors under the seats. If you knock a coin against these without the foam, all you get is tinny noise. After the foam, the panels sound dead, which is what you are after. The next issue is the area where the roll gage transits the firewall. If you put your hand up while driving, you will be astonished at the amount of heat and noise that passes thur that gap. The product Seals It is an aluminum ring with a rubber gasket attached that you rivet in place. It does a great job. I also advocate wrapping the water pipes running down the car's side in header wrap.
The next level, maybe only for those in warm climates, is to eliminate the heater core. I sourced an A/C core made by the same manufacturer that Ultima uses, which makes a direct replacement for our heater core a/c heat exchanger. Now, the A/C. works even better. The stupid heater valve doesn't leak hot water into the exchanger when it's not wanted, and you eliminate many hoses, weight, and complications. I live in So Cal, so a heater isn't needed. Others will need to make that decision for themselves.