Engine sound pad question... which one to use?

[defcon65]

Didn't know, thanks for the heads up. Isn't there a peel and stick neoprene material used for the same effect? That's what I'm looking for. I saw it used to line an inboard boat engine compartment, and I've seen similar stuff in car audio installs. It's about 3/8" thick, very dense with adhesive on the back.

I don't mind the engine sound so much, but the adhesive residue looks like rust and I want to clean up the engine compartment.

[randywebb]

They make something for underhood use - it might be ok on the motor side of the firewall. Likely heavier than the stock pad tho.

One thing is you sure can't beat that price.

I am wondering what makes him say the product is the best one made - do you know? Or is it just 'company pride?

[911pcars]

"He says it's the best sound deadening material out there."

Could be, for audio purposes, but it's heavier than some alternate materials. There are other sources for basically the same material, but w/o the Dynamat trade name attached (makes it pricier).

Sherwood

[gsmith660]

I am doing a complete restore so I am going to put my sound mat on the other side of the sheet metal and leave this nice looking paint

[Poohsan]

That looks KILLER!

[JeremyD]

I have the bling bling Yo Boy foil backed - trimmed appbiz aftermarket sound pad - it's light - it deadens the sound on par with the factory pad, it doesn't fall apart, and I have seen no difference in engine temps even running a larger displacment, hotter cams and higher compression

[911 in SC]

Jeremy, did you buy the sound pad with the perimeter binding or without? How's the heat inside the car? Any different?

Thanks,
Mike

[JeremyD]

With binding - no difference in heat or sound

[911 in SC]

Sorry for all of the questions BUT did you try it without either sound pad? I don't have a pad now, and the rear seats do get a little warm. I'd like to keep the temps down, as my 7 yr. old daughter doesn't complain, but I want to keep her as comfortable as possible. If the pad will reduce temps inside, it's well worth it. If not, I'll keep my car the way it is (it sounds great!).

Thanks,

[RWebb]

Once heat or noise 'hits' the sheet metal it is much harder to deal with. The sound pad on the engine side is going to be much more effective at both heat & noise control.

OTOH, that bare but finished texture does look good - so if you have carbs or something that let's you see the firewall, then you have to balance the visual w/ the heat/noise issues.

I prefer the Al foil type pads if you want that maximum "Roasted Chicken" bling effect.

[911pcars]

I installed some Mylar-backed, 1" foam material out of the JCWhitney catalog; created a pattern with paper, tape and scissors, then transferred onto the material. Added Mylar tape to cover the cut edges. I believed I used contact cement on the bulkhead as well as the foam.

Since my car was out of commission for years when I did this, I can't speak for the sound or heat reduction of such a pad. As a wag, i'd say it reflects some heat and reduces some sound.

2-year old photo:


Sherwood

[JeremyD]

Ha Ha - knew Randy would chime in - Do you think that's why I am getting all this HP? Maybe the foil backing is focusing the power waves from the flux capacitor...

[JBO]

I used the same stuff Sherwood used, but I got it at Pep Boys. I wasn't concerned about the sound, and was mainly concerned about a hotter passenger compartment with no pad. It has been in place a few years now and seems to work well.

[gsmith660]

Im going on the same principle that you put dynamat on the inside fo your doors to stabilize the metal and on the outside of the inner door panel to cut vibration from the stereo resonance

[RWebb]

regular Dynamat works primarily by making the panel heavier

a heavier panel has a resonant frequency that is lower than a lighter panel; the peak amplitude ("Q") is also reduced

an analogy is sticking wad of asphalt on a kid's drum head - the metal panel is exactly like the drum head (since drummers tend to have strong forearms, this experiment is best carried out using a young kid)

[gsmith660]

I always thought that it was kind of like the the radar absorbant material on planes it would slow down the wave as ait traveled thru the material until the amplitude dropped off to 0

[911pcars]

Just to add another theory;

I thought the added material changes the vibration frequency of the base material.

Quick. Someone call JCWhitney tech support for the answer.

Sherwood

[RWebb]

"changes the vibration frequency of the base material."

- isn't that what I said??

[911pcars]

Originally Posted by RWebb

"changes the vibration frequency of the base material."

- isn't that what I said??

Randy,
Yeah, but I wanted to say it too.

Sherwood

[gtc]

After reading this thread this morning I went out at lunch and pulled out my old, falling off and apart factory pad, then went for a drive. There wasn't any appreciable difference in sound levels.