miata2fast

iTrader: (2)

Aren't you a little concerned about all the extra added pounds?

Jeffbucc

I'm ridiculous I know. With this stupid dry cough I sleep even less so I just go out and work on the car for a little bit.

Started out as such and evolved from there. I think it will be more of a weekend/auto-x/track day car rather than a full blown track toy. I just wanted a little refinement on the days I drive it to work or go for a spin.

Bad thing about being in Southern Utah, there are not a lot of auto-x events nearby, so you have to drive quite a bit to get to them.

Jeffbucc

The car had about 280 hp on a conservative tune before it was wrecked so I'm not too concerned about adding 10-20 lbs of noise cancellation.

I have removed more than that in undercoating/front hood support bracket/ac components/wiring alone, so it'll cancel out.

18psi

iTrader: (76)

I bought 100sq/ft of Dynomat sound deadening for my miata. Ended up using only like half of it, but covered EVERYTHING inside. Literally, every orifice. Check my thread.

You know what the total weight of all 100sq/ft was? 15lb

That is nothing. And the reduced nvh, noise, and overall solid "feel" of the car on the road is SOOO worth it. I'd recommend to everyone that daily drives their miata

Braineack

iTrader: (62)

I did nothing but add weight to my miata. didn't bother me. you wanna know the best way to combat added weight? up the boost.

hornetball

iTrader: (4)

LOL. In my case, go on diet.

Jeff, in addition to meme, I nominate you to be the official mt.net chemical engineer.

Jeffbucc

Why the chemical engineer? I think that would be a bad idea...lets just say if you fumigate yourself you may not take legal action against Jeffbucc incorporated.

hornetball

iTrader: (4)

You always seem to come up with the right witch's brew to reverse 25 years of aging and wear/tear.

concealer404

iTrader: (3)

Did the manufacturer of that mat recommend 100% coverage? That's a bit odd.

18psi

iTrader: (76)

this is a GREAT idea, and will make your miata a treat to daily drive

Seriously - people don't realize how big the difference is unless they drive two miata's back to back one with one without. I was impressed
its probably not necessary, but why not?

turbofan

iTrader: (1)

Many of these "sound deadening" mats are not actually sound inhibitors in the way we think of them. Many of them are really just designed to reduce the vibrations of the metal to which it is attached. Most manufacturers recommend strategically placed mats so that you can use the minimum amount of mat for maximum effect. I presume this is why Concealer asks his question. Of course, usually when manufacturers recommend placement like that they're trying to stabilize a door panel or something instead of a floor pan.

Although I think Jeff has the right idea. The "heavy" dynamat type stuff will stabilize the metal and keep it from vibrating and resonating. The closed-cell foam will actually act as a genuine sound barrier. I'm not familiar with the vinyl part though.

concealer404

iTrader: (3)

Well, 100% coverage CAN result in more vibrations than a lesser percentage, depending on how it's applied. There's no way it's not going to be a huge improvement either way, was just curious what the instructions specified, if there was any.


Ah, i got ninja'd. That explanation makes sense.

turbofan

iTrader: (1)

Yeah... if he had even more time and even more science and research, he could probably do a little better by placing it strategically rather than putting it everywhere. But not even Jeff has time for that. Much easier to just do full coverage rather than try to put it here and there. This is going to be amazing when it's finished, the closed-cell foam will make a huge difference.

Jeffbucc

Luck!

USually you want to since it is a vibration layer rather than a noise deadener, this makes it so panel flex is minimized and less noise as a result of that.

I'm hoping it works as well as I researched it to. Stuff is HEAVY though. Noise cancellation was big on my to do list after driving both the cars over long distance. I literally couldnt drive both the highly modified and the "stock" car without noise isolating headphones on. It was ridiculous

It may be overboard going with 100% coverage like that but the Miata has a lot of panel flex points from what I've seen. Many areas that can transmit and produce sound, or let sound into the car.

The vinyl stuff is the creme' de la creme' on the sound "deadening". The foam helps kill a certain frequency range while the thick vinyl help take care of the other spectrum or noise "range". It is the heaviest part of the noise deadening equation but you get the biggest result from it.

I wish I did have more time, I'll be buying a couple more dynamat sheets for the inside of the doors, not sure what I'll do in the trunk area since I wont have any more closed cell foam or vinyl for it.

Spray and pray was my goal on this....no I wish I could go into this completely without research. The full coverage helps the noise not have a path to get through.

Most the times you see the spot applications is when they are trying to isolate high stress areas for speaker systems where they see enhanced vibrations in certain zones in the car depending on what music they are playing

Here is the completed closed cell foam installation. It honestly looks terrible in the photos only due to the fact that the glue hasn't dried and "cleared" yet. It looks pro in person...or as well as I could get trying to stretch 36 yards of foam for the cabin area.

Super 77 3M spray and High strength 90 is your friend.







This is really really tedious work.

Fireindc

iTrader: (13)

Looks like it's gonna be quiet in there, lol.

karter74

iTrader: (4)

In case anyone wants a good reference on sound deadening in a car:

Welcome to Sound Deadener Showdown | Sound Deadener Showdown

Jeffbucc

Yup that is a great site but you need to build your base information/knowledge before you can understand it. Lots of upper level audio guru nerdifying.

Jeffbucc

Found out that the Mass loaded vinyl needs to be a little "loosey goosey" for it to absorb properly. If pulled taught then it is less likely to absorb the higher frequency sound waves.

The hard thing about MLV is that you need to minimize breaks in the material as much as possible. Obviously on the firewall you are going to have a hard time minimizing that while still being able to fit the firewall rubber gaskets in their associated holes.

So I plan on seam taping the segments together with aluminum tape or, if I have enough, gluing spare MLV scraps together to further isolate chance of sound escaping. We'll see if I care enough by that point, ready for this "project" to be over

Measure 20 times cut once.



Slap it on.

Fireindc

iTrader: (13)

damn dude. I'm curious to hear if this was all worth it in the end.

Probably will depend on the person and the use of the car, but i've always removed weight from my car in the past. However, at this point my car is too loud, going with a nice quiet 3" to see if I can get it to acceptable levels, but I guess this would be the next step

Jeffbucc

Haha we'll see. I'm saving the trunk for another day. I have a whole vinyl mat left over that I'll save for that when I figure out what I want to do in that area.

It is such a small amount of weight that I really don't care. Its sixes at this point. I've removed so much weight that I think I'm still in the negatives vs weight added. I have a loud 3" exhaust too so this'll help I hope.

After this I'm putting the hard lines and gas tank/filler/breather tube in.