Sound Deadening (how much difference)

[Minkota]

I recently checked the sound decibel rating in my truck and it was over 100db.

I have 4 boxes of
Siless Hybrid 3in1 200 mil 25 sqft Car Sound Deadening mat - Butyl Automotive Sound Deadener - Noise Insulation and Vibration Dampening Material.

I have 2 boxes of
Siless Liner 157 mil (4 mm) 51 sqft Aluminum Foil Finish Car Sound Deadening & Heat Insulation Closed Cell Foam - PE Foam Sound Deadener. this will be laid over top of the previous material.

I am planning to do the entire cab floor, back wall of the cab, as much of the firewall as I can, and as much of the doors as I can.


Does anyone know how much of a difference this will make?
Will it be worth all the work?

I am not looking for suggestions on which products are better, I received this as a gift so this is what I am planning on using.

[Grumpy old man]

Sounds like a lot ? What carpet/flooring are you using ? What exhaust is in it ?

[Minkota]

Originally Posted by Grumpy old man

Sounds like a lot ? What carpet/flooring are you using ? What exhaust is in it ?

It has the basic carpet and padding from LMC with 3" exhaust and Flowmasters.

[Grumpy old man]

Well there's the noise problem 3" pipes with flowmasters is going to be LOUD , Order the Mass backed ACC carpet from Rockauto .

Reasons to get Mass Back carpet:

Improved sound deadening. Improved heat insulation. Easier installation - no need to add extra insulation to the carpet kit and jute padding. Adds a solid waterproof layer between the carpet and the floor pan, allowing the owner to wet vac the carpet if needed.

[72SB]

Given you already have carpet and pad, additional sound deadening under that, behind seat and firewall will help....but a bigger change would be to consider another muffler if you have Flowmaster 40's.

The Flowmaster FX would be a quieter alternative and still have a nice note. The FX is not a chambered muffler and sounds more like MagnaFlo or Dynomax mufflers (non chambered), but just richer IMHO.

[Accelo]

Some good suggestions to lower the db.
Outline the conditions when you acquired the reading would help.

It is my experience it you can attempt to keep the sound level down or?
Just not make the noise to begin with.
Different mufflers are in this category.
Are you running an overdrive transmission?
A OD transmission makes a huge difference any time the vehicle is in OD.
When every I install one this is typically the first comment, it's quite in here.

The fan makes a lot of noise. Stay with the stock design.
Consider going to an electric fan. On cooler day my fans doesn't even came on, even in town.

But I still have the exhaust issue like you have but it unlikely as loud (2.5")
But I like it that way. Still I don't leave without the neighbors knowing.
Cheers.

[HO455]

A long time ago someone told me about doing this and for years I was skeptical but I finally became a believer. If you turn this knob, like this, it will help. Who knew?

Seriously though, do you have headers? Are your wing windows sealing properly? Have you considered tire noise as part of the problem?

Personally unless I was running 600 hp I would replace the 3 inch pipes with 2 1/2" ones and I would throw the Flowmasters in the scrap barrel to be replaced with Walker Dynomax 17749s.

The less noise produced the less noise you need to dampen.

If you're set on keeping the Flowmasters the look into installing some J-tubes/Helmholtz resonators. I know there is a thread here on them and if my memory hasn't failed today LockDoc has run them.

See links for further muffler information.

https://www.pontiacstreetperformance...p/exhaust.html

https://www.summitracing.com/parts/w...SAAEgKivfD_BwE

[cj847]

To answer the OP question, yes, the sound deadener is worth the effort. It is especially important on flat surfaces. IMHO you do not need to cover 100% of every surfaces, but if you have enough material that is fine as well. Anywhere 2 pieces of metal are welded together or there is a bend vibration is reduced so I don't cover them.

For the thermal barrier the more the better esp over the trans tunnel and firewall. And the floor if your tailpipe and muffler are close to the metal.

But, as stated, sound deadener will not eliminate wind noise and exhaust noise.

[LS short box]

Is the exhaust all the way out to the back bumper? Since you have the sound deadner I would install it on the floor and fire wall.

[Getter-Done]

Yes, it makes a Big difference.

I just helped my nephew put down the same/similar stuff.

His truck had a rubber mat.
So, I definitely wanted to put this under it for him.

If you have not already got a Roller to roll it down with,

I would buy one.
It really helps make the job easier and smoother results.

Link to roller below

Link: https://www.amazon.com/LUMITECO-Auto...7W9BTN6G&psc=1

Link: https://www.amazon.com/FCHO-Deadenin...7TV19PQF&psc=1

[May70]

Have you ever owned 40s? They are loud and drone horribly.

[Impact02]

I did my truck with just the butyl type. Had it apart pretty far so I did the whole thing firewall to back window. Put the rubber mat on top. And it is fairly quiet. With a big block 3 in exhaust to the bumper jets knock off flowmasters.

[72SB]

Originally Posted by May70

Have you ever owned 40s? They are loud and drone horribly.

Yeah, they are the classic loud muscle car muffler. To give an idea of how loud compared to their other offerings...

https://www.holley.com/brands/flowma...flowfx_series/

[ghackett1]

Originally Posted by 72SB

Yeah, they are the classic loud muscle car muffler. To give an idea of how loud compared to their other offerings...

https://www.holley.com/brands/flowma...flowfx_series/

I have the flow master Delta 50’s. I got them because they are supposed to decrease drone inside the cab. But I cannot compare them to another system because that’s what I used from the beginning. I like them.

[HO455]

I have a Delta Flow 50 on my 4.3 Blazer. It definitely drones. The claim is reduced drone but how much isn't really quantifiable. Any drone is bad in a street car that sees any trips more than 30 minutes. I use the overdrive to avoid the rpm where it drones (around 45 to 50 in OD). Best to avoid mufflers that cause drone if you want to still hear when your 60.

[LS short box]

Back in the day I used Flow Master mufflers. Today I've used nothing but Dyno Max turbo mufflers. Still sounds good but zero drone.

[Steeveedee]

Originally Posted by HO455

I have a Delta Flow 50 on my 4.3 Blazer. It definitely drones. The claim is reduced drone but how much isn't really quantifiable. Any drone is bad in a street car that sees any trips more than 30 minutes. I use the overdrive to avoid the rpm where it drones (around 45 to 50 in OD). Best to avoid mufflers that cause drone if you want to still hear when your 60.

Oh, you'll be able to hear. It'll just be this high-pitched whine that doesn't go away. Or that sound that the second grade teacher in the "Peanuts" cartoon used to make.

What's that, honey? Yes, I'll go pick up the mail. My wife better never get ahold of my passwords...

[Accelo]

I have a 2.5" Black Widow muffler. I have the Venom 250's. Not too loud for cruising or idling but it does get loud with power. No Drone what so ever.

I love their marketing. Mufflers types below;
Neighborhater, Widowmaker, Angry Housewife, Race Venom, Venom 250 and Venom 300 Mufflers.

All stainless steel. No other option.
Cheers

[Minkota]

Originally Posted by Minkota

I recently checked the sound decibel rating in my truck and it was over 100db.

I have 4 boxes of
Siless Hybrid 3in1 200 mil 25 sqft Car Sound Deadening mat - Butyl Automotive Sound Deadener - Noise Insulation and Vibration Dampening Material.

I have 2 boxes of
Siless Liner 157 mil (4 mm) 51 sqft Aluminum Foil Finish Car Sound Deadening & Heat Insulation Closed Cell Foam - PE Foam Sound Deadener. this will be laid over top of the previous material.

I am planning to do the entire cab floor, back wall of the cab, as much of the firewall as I can, and as much of the doors as I can.


Does anyone know how much of a difference this will make?
Will it be worth all the work?

I am not looking for suggestions on which products are better, I received this as a gift so this is what I am planning on using.

I just finished putting the POR-15 on the Floor this weekend.
Does anyone know if the Butyl should go on first or should the Closed Foam be the bottom layer?

[Woody]

The Black Tar Paper goes down first with the Foam Pad on top.

Woody

[Minkota]

Originally Posted by Woody

The Black Tar Paper goes down first with the Foam Pad on top.

Woody

ok thank you, just wanted to confirm I was thinking correctly.

[Minkota]

So far I have painted the floor with the POR-15, and applied the first layer of the Siless sound deadening material. Hopefully the weather will hold out so I can apply the second layer and reinstall the interior this weekend. I am waiting for my order from GMC Paul so I can redo all the seals in the doors before I install sound deadening in the doors.

[SCOTI]

Another option (layer) that high-end vehicles use (OE production type) is Mass Loaded Vinyl.

I used the foil backed butyl as the first layer for temp isolation & noise/vibration cancellation.
The layer of closed cell foam as the 2nd for sound absorption.
MLV as the next layer for sound isolation.
Carpet.

My dually has 1.75x3" full length headers w/3" In/Out Dynomax 17749's under the back seat (crew-cab). The exhaust piping reduces to 2.5" tail-pipes w/45° bends angled down under the rear bed corners. It will set-off car alarms cruising through a parking lot if you get close enough but is as quiet as stock restricted exhaust from inside the cab.