Dynamat: What thickness should you use? should you put over the tar on the floor should you throw away the rubber pad behind the backpad on the firewall?





I need some adivce: I want to add sound barrier under my backpad and possibly floor. I currently have the black tar floor, nothing in doors and rubber pad behind backpad which honestly has seen better days and looks pretty nasty.

Should I add any sound proofing to the floor before I carpet? If so, what thickness?

Also, should I throw out the old cracked and dirty rubber pad and put sound proofing on top of the firewall behind the backpad or leave it as is?



Thanks in advance for advice

I used a bunch of Noico brand sound deadening pads. They worked well. However, I would not buy them again since they are mad in the Russia war criminal nation.

Sound is both vibration and sound waves.
It’s best to use two types of material to stop most of the sound waves.

Lizard skin is a ceramic paint, good for step one.
Ice and water shield type self sticking rubber is the second layer.

We have real estate issues, so you really can’t use anything thick like wool padding still found on high end luxury cars, it’s too thick.

If you go google about this topic, google dynamat and lizard skin along with sound waves….some good learning out there

Coco mats is the best sound deadening floor mat I've used. Seriously, after I installed them my interior noise level went way down. They're a thick mat with a rubber backing, perfect material for sound deadening and they look good too!

Selective application of sound deadening mat will help the doors sound more solid/less tinny.

I’m debating how much of the interior metal firewall to cover with sound mat, leaning towards all of it.

Trying typing “914world.com sound deadening” into good and look at the image results, lots of ideas there as noted above.

Biggest difference for me was adding several 75mm wide strips inside the doors,added thin material over the floors and that made little difference,I also put under hood sound deadener on to the rear of the backpad of which a small improvement was noticed.
Real hard to tame the noise from a "6" ,going back to stock air cleaner from K&N's made a huge difference however.

Interesting to know. That is good to know.

I will definitely put some oi the doors, but do you have any thoughts on my question about 1) thickness and 2) should I put over the tar matt and the existing rubber back pad on the firewall or not?

Any thoughts on this subject? I

Dynamat must be applied to sheet metal.

Putting it over OEM tar on floor or the existing back pad will have no effect.

There are two thickness of Dynamat. If you look at the test specs on line - you’ll see that the effectiveness is proportional to the mass and thickness of the mat. I’d recommend the thicker Dynamat unless you’re really trying to save weight.

I already had put X-Mat (same as Dynamat) on the interior rear firewall.

I am guessing not much further improvement would be made by also placing it on the engine side of the firewall.

I have considered an engine mat similar to the original thick mat in the engine compartment.


Click to view attachment

Maybe something like this - cheaper and lighter than the original...
https://www.rix914parts.com/store/p29/914_F...uction_Mat.html

no affiliation.

I have one of those pads and it is made of a very pourous material like is used under modern hoods to reduce heat transfer. I doubt it will do little to reduce sound.

the 914s are quite quiet when in stock dress so by restoring the original sound deadening to the floor, the back wall and the engine compartment and making sure that the rear window is well sealed you will be all set. Don't waste time on snake oil solutions like lizard what ever or what ever