Sound proofing options, and exhaust question

[david85]

Since my truck cab is almost ready for paint, I'm starting to think about ways to sound proof the interior before putting it back together.

No plans for subs or any kind of fancy sound system, but rather how to reduce wind noise and exhaust drone. Specifically, I was never able to eliminate exhaust drone. It isn't super loud, but it does get tiring on longer drives causing headaches and fatigue. And since this truck can easily cover half a time zone on internal fuel, it would be nice to enjoy it a little more on the long trips I built it for.

Did a search on previous topics and came up with this list of options:

Dynamat - overpriced
Fat Mat - better cost, but still a premium

Peal & Seal - tar based, might result in odor or separate in hotter climate, low cost
Frost King duct insulation - high density foam backed foil, intended to control and sound and heat (How well?) low cost
E - Z Cool - lightweight foam core foil insulation - also intended for sound and heat (claimed 97% IR blocking) low cost

Right now I've just about ruled out expensive options like dynamat and lizard skin but still welcome any feedback from those who have used them.

Engine bay insulation is also pretty much toast. I tried to salvage what I could but would rather not put junk back into a freshened up truck. The area around the turbo and down pipes would also have to be fairly heat resistant too.

Finding something for the hood probably won't be too hard but what about the firewall and plastic wheel wells? Has anyone tried replacing the OEM fiberglass matting in these areas?

Now regarding the exhaust. The muffler is located right at the rear wall of the cab. Could this be causing some of the resonating drone I've been experiencing? Would it be worth shifting it further back under the box? Funny thing is, it was straight piped at one point and still had the same drone. The muffler killed the noise outside, but did almost nothing for the drone.

 

[catbird7]

I removed all of the underhood insulation with the exception of firewall simply because it looked terrible. Used peel & seal on every surface inside the cab. My exhaust is 4" with no muffler and exits on passenger side behind rear tire. This combination is OK, I can hear the turbo with passenger side window down, however I wish it was quieter inside cab with windows closed. My truck is black and it was stinkin hot this summer and there is zero smell of tar or asphalt and none of it fell off the ceiling. If I was doing this job again, I'd start with something like bed liner coating inside cab first, then add peel & seal (maybe two layers). Also good quality carpet and shifter boots make a difference. Other noise makers include poor quality seals around windows & doors plus consider tread design on tires.......

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[FORDF250HDXLT]

i went with;

EZcool.-it's so thin you need 2 layers though.

for your drone issue,i can help you cure that easily.get yourself a walker big truck muffler.it has a built in resonator just for this.
install it as far back as you can.preferably hook your tail pipe into it.

these two things iv done to chip truck and at first you had to yell to someone sitting by you.now you just talk normal.it was worth every penny.
two layers on the floor,behind the carpet going up towards the rear window and in the doors.
for the firewall.at least 1 layer of it on the engine side.unless your truck came with the thick black firewall mat.log truck did(iirc i could peek in the 9th gen banks turbo install thread but im too lazy this am lol). chip didn't.

it might not be the best $ can buy or anything but i bet you'd think you were riding in a totally different truck if you do both of these.hope this helps.

edit.yes.do yourself a favor.run the exhaust out the whole way.you'll thank yourself,you did.

 

[franklin2]

Lowe's sells that Grace roofing water shield. It's not cheap, about $80 a roll but it' a big roll. It's the stuff you stick on down at the gutters before you put the shingles on.

One thing I have found that will cause a drone inside the cab is the exit of the exhaust. It must be past the body of the truck. If the tailpipe exit stops between the body of the truck and the road, it will cause a loud drone in the cab, even if it's under the bed. If it exits out the side of the truck, make sure it's at least even with the side of the body.

 

[IDIoit]

first I painted the inside firewall and front floor with this.
http://www.ebay.com/itm/Als-Liner-A...ash=item4d491e3624:g:Qt8AAOSwFEFXI8ec&vxp=mtr

then I layed this down
http://www.homedepot.com/p/E-O-12-in-x-15-ft-Self-Stick-Foam-Foil-Duct-Insulation-FV516/100028603

quieted things down tremendously after the inside insulation and carpet were back in.

door and window seals are a big part also.

 

[hce]

Take a look at sounddeadnershowdown,

 

[laserjock]

Rob (F350camper) did a pretty thorough write up with sound data on his ranger. His thread is in the conversion forum. Might be worth checking out his findings.

 

[david85]

Wow, that's a lot of feedback. Thanks guys

Just a clarification on my exhaust; the tailpipe does dump at the stock location behind the rear wheel. It extends about 5" past the lower edge of the body. Only the muffler is physically located at the rear wall of the cab.

Regarding weather seals, I'll be junking my aftermarket door shell (whistles above 35 mph) and using only ford OEMs when I install all new weather seals from bronco graveyard. Hopefully that will make a difference. The roof has also been stiffened and reinforced which may or may not reduce resonance. Have to wait and see.

FORDF250HDXLT Do you have a link or part number for that muffler?

hce I've been searching for a while, but didn't find that website yet. Good info there. Cool, they even have MLV.

IDIoit That looks suspiciously like lizard skin before getting an expensive sticker put on. Very interesting...

franklin2 That's another one I haven't heard before. Thanks.


So has anyone found a possible solution for the wheel wells in the engine bay?

 

[79jasper]

I don't know how the price compares to the rest, but Eastwood has some stuff like that now.

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[homelessduck]

I covered my floor with peel and seal. It made a huge heat difference and a noticeable decrease in sound. Best part - i spent like $30

 

[firehawk]

I use the cheapest insulation on a roll I can find. Heavier is better. Never tried liquid or spray on. Be sure to do the doors, as lots of noise comes in through them. If you can, do a layer behind the door panel and another layer on the door skin. Big flat panels, especially if thin, will vibrate and transmit more noise. Roof is often the biggest, but it is farthest from anything that makes noise.

 

[FORDF250HDXLT]

FORDF250HDXLT Do you have a link or part number for that muffler?

you've seen my records list.what kind of question is that? of course i do.
the part number is 21470

and here is a link;
https://www.amazon.com/Walker-21470-Muffler/dp/B0017LWGMQ

though you might try simply moving your current muffler back first.might be all it takes and not cost anything.

 

[icanfixall]

I used Fat Mat.. I learned from Darrin about this material. I used 2 layers of it and sure is a quite ride now. I did the walls, doors and floors. I could not drop the head liner without removing the windshield so it was not done.

 

[typ4]

So far I have done the pass door with dynamat. Huge difference. Cant wait till I get the rest of the cab done. I am also going to line the inside of the cowl with it. Lots of resonance thru there since its a previous gasser.

 

[franklin2]

Another place for noise on a N/A truck is the air cleaner. Anyone ever wonder what the soup bowl was for? Ever noticed the noise you get from the engine after you cut it out? Does the soup bowl cost hp? I don't know. But it does cut the intake noise down.