How much sound deadener for an FD?
 

I'm going to sound deaden my entire FD, but before I place an order I want to see how much sound deadener you guys used. I plan on doing the entire floor, front to rear, as well as the doors. Thanks

what are you using? i used quiet coat (liquid) and used less than a gallon...

What part of the doors did you coat? I'm going to be doing this very soon as well.

I'm using the normal mat style. Guys on norotors.com used 80-100 square feet for the floors doors and roof. I ordered 100 sq ft from fatmat.com. Heard nothing but great things about it and it was only $130 shipped :)

I used 2 1/2 gallons of quiet car in my FD.

I coated about 90% of the inside of the door skin, and 100% of the interior portion of the door.

The sound deadening thread ^above^ has pics of the rear half of my FD covered with Dynamat. If I remember correctly, D. Hayes got kinda pissed for some reason(?). But I don't take stuff like that personally. As an installer and fellow forum member, I contributed what worked. The goal of my install was to reduce vehicle noise, which I accomplished.

I would hold off on deadening the ceiling. There's not much benefit in doing something like that.

Start with the front of the car's interior and make sure to apply the mat to cover the large punched holes in the metal kick panels which allow engine, road and wind noise to enter the cabin. I'd like to see someone try to use liquid anything patch that up ;).

The rest of my pics are self-explanatory. There's bigger pics in the West Forum "post pics of your ride" thread.

The amount you specified won't be enough if you're planning on doing the floor and the doors, but if you start from the front of the car, you can still drive the car and finish the trunk later. You may also consider one layer on the trunk separator - the big ~ 4' x 1' piece of plastic that separates the trunk from the cabin.

For ppl who undoubtedly will try to comment that that piece doesn't do anything, try driving your car with and without the separator in place. You don't need a dB meter to intuitively acknowledge that one layer on the trunkside of that piece would reap benefits as well.

When you're done with your project, be sure to post an honest objective result of your efforts, for example, "girls no longer get headaches from riding in my car..." or "I say what a lot less now." :)

I can understand sound deadening the floor and doors, but what benefits does one gain when deadening the trunk?

The trunk area is a place for all the workings from the rear of the car to translate noise/vibration into the cabin. Think about the rear end, suspension, and tires back there. There's quite a bit of noise that comes from back there..

Thanks for the info! I stopped reading the stickied thread above since all the pics people were refering to were no longer there, I'll have to go through it again. I've read several cases where people did the roof and noticed a huge reduction in wind noise, figured I'd give it a shot. I would give a before and after comparison except I bought the car as a roller so I have no idea what it sounded like.

Plus the fuel pumps. Also, the spare tire well acts as a reverb chamber ;)

Shit, i coulda saved all my OEM deadening and sold it to you when i scraped it all off!

I didn't get pissed I just pointed out factually incorrect information you posted about Quiet Coat.

Regarding why to do the trunk, any surface that can transmit vibration is an area that can benefit from sound dampening so that means the entire interior surface of the car, including the trunk. I posted up a thread on soundproofing my car with Quiet Coat with actual decibel reductions included:

https://www.rx7club.com/showthread.p...ght=quiet+coat

The trunk area yielded the least sound reduction, with a reduction of 1 to 3 decibels. Didn't know back then that 3 decibels was a 60% reduction in sound energy but you won't notice much reduction from doing the trunk.

Overall, I reduced noise by 13 decibels which is a huge gain. Here is a chart of each phase I did and the results:

https://www.rx7club.com/attachment.p...1&d=1183392340

Phase 1 was the trunk, phase 2 the doors, and phase 3 the underbody.

Damn David, thats some hardcore TRUTH right there! Very badass!

Yes, the numbers don't lie :)

I would have used the liquid stuff on the interior but it doesn't deflect heat at all. The under coating that I used on the entire underside of the car has sound deadening material in it though

A solution to this is to use the Quiet Coat on the interior and then to use some DEI heat shield over the under coating on the bottom of the car. Works well. And FYI - the undercoating spray on material is nothing like Quiet Coat so its sound deadening material will not perform anywhere close to the level of Quiet Coat which is from 6 - 20 decibels on the normal car. I was right in the middle of that range on mine, with a 13 decibel reduction.

I just ordered a gallon for the doors and if there's enough left, the roof. It wasn't the best option for what I wanted to accomplish on the firewall, dash, trans tunnel and floor boards

fwiw, I bought 100sqft of Fatmat "Rattle trap" for my FD. Per their advertising, the rattle trap is like doing 3 layers of fatmat "extreme". I've never touched "extreme" so I cant verify.

Its a ton of work. I am around 14hrs or so into it. I have done the trunk, most of the floor, (Up to about the shifter, would have to remove carpet to go any further forward) and the doors. Its looking like I will have enough left to also do the roof.