2nd Gen Non-Engine/Transmission Reducing Interior Cabin Noise Levels

[GZagorsky]

I own a Ram 2001 HO 6-speed long bed dualie w/extended cab and am interested in quieting the interior noise levels below what they are now. Local drives don't bother me too much but this summer I'm planning on taking my 5th wheel RV trailer out to Rockies and thereabouts. My family will be along and listening to the truck's exhaust drone for hours at a time has proven to be quite tiring, to saying nothing about being hard on the hearing, even after the engine is shut down for the day.

Any comments/suggestions (including product names) about how to address this successfully would be greatly appreciated. BTW, I've already replaced the exhaust system from the factory exhaust brake back with a 4" MBRP unit.

---Gene Zagorsky

 

[Boondocker]

You might try searching on NOISE REDUCTION, although some of the threads are over a year old.

Having read all the threads I can find on the subject, I decided to start with the viscoelastic method. While the Noise Killer brand product has received some coverage, I decided to try the other brand, QuietCoat.

My initial investment is $150 for 2 gallons and the sprayer kit. With the spray method, you spend about half the project time masking off the surrounding areas that you DON'T want sprayed.

I started with the back wall of the cab, since it's easy to access and blatantly in need of coverage. Spraying it on was delightfully easy, no cutting, trimming, gluing, scraps or odor. I applied 2 coats with about 3 hours drying time in between. There is very little odor when wet, a bit like concrete and no odor at all when dry. It's grey in color, like concrete and dries hard, like, you know.

Next up was the hood. Since DC shorted me a hood blanket, it was naked too. I masked all around the interior edge of the hood with masking tape and newspaper and covered the engine bay with a big drop cloth. I used masking tape to cover all bolts, hinges, light fixture, etc. First I sprayed through all the holes in the supports to cover as much bare metal as possible, plus spraying a little extra on all the "triangles" between the supports. I decided to splurge on the hood and did three coats.

All of this used 1 gallon. My next candidates were the oil pan and plastic inner fender liners nad maybe some exhaust wrap. This stuff is brushable, and due to the tight quarters around the oil pan, that would be the way to go. Get some fender liner fasteners, shouldn't be too bad to remove them, spray and reinstall.

Don't ask about decibles, don't have a meter, to late to compare. This is a sensory perception thing for me, so I'm not concerned with empirical data. The first perception, with my wife behind the wheel, is that it is noticably quieter. That's the verdict.

Overall I'm pleased. I got reasonable results for a reasonable cost and effort. To do the whole job, you have to get ambitious and tear up the interior.

For statistic's sake, my coverage map went something like this:
Hood - 3 coats
Cowl - 3 coats
Fenders (outer) - 3 coats
Plastic Fender liners (inner) - 2 coats
Oil Pan - 2 coats sprayed, 1 coat brushed
Doors (front and rear) - 3 coats
Back wall - 4 coats
Floor - 4-6 coats

My stock stereo sounds surprisingly good now
Road noise on asphalt is almost gone.
It's pleasant in the cab. The Cummins is ever-present but not overbearing.
I would like to compare to a stock truck and maybe to one quieted with a different approach.

I'm happy with my results and hope yours turns out as well.

P. S. Welcome to the TDR!

Neil

 

[randrade]

quiet please

I have done one layer of dynamat on the back of the cab behind the seat, as well as a layer on the entire floor. Put a small amount right above the turbo, as well as the valve cover. It all made a noticable difference. I used a layer of lead to make a sort of cover for the valve cover also. Looking to pull out interior and do a layer of lead on the floor and another layer of dynamat this summer. Also the doors will get done.

 

[DShore]

There are several products available to deaden sound, but you are really missing the boat if you do not also insulate against heat as the heat resistance in a Dodge cab is non-existent.



I removed all of the interior including the headliner... sprayed QUIETCOAT on top, back wall and floor after masking off everything you don't want overspray on.



Went to the local auto parts/paint store, bought an undercoat gun and a couple feet of fuel line to suck it out of whatever container you use... total cost about $35 for complete setup. I sprayed 5 gal of QUIETCOAT on above mentioned parts. Ended up being about 1/8" thick.



Then I put 5/16" thermal mat on top, back wall and floor. The adhesive they try to sell you is nearly worthless. It will not hold the mat on the top or back wall. I used DAP Landau top and trim adhesive Part #ADH233G, this should be available from a good auto trim supplier.



Clean out your undercoat gun after spraying the QUIETCOAT and use it to spray the adhesive on both surfaces... meaning truck and thermal mat... in a well ventilated area with plenty of air movement. All thermal mat pieces for the roof, floor, etc should be cut before beginning each area of installation. Best way is to let each piece dry before install. Make sure the parts are where you want them when you put the two glued sides together, as there is only one shot at it. This is strong stuff. (Make sure you wear a mask suitable for spraying toxic automotive paint when using this adhesive... I also wore it while spraying the QUIETCOAT. )



I also removed the door panels, but only put the thermal mat on the plastic inner door panels. You will have to cut many small pieces to fit between the braces on quad-cab doors and brush on the adhesive. It is a time-consuming job, but well worth it. Clean out the undercoat gun with lacquer thinner or acetone and save it for your next project. Now reinstall everything. The headliner will be a tight fit and you may have to do some trimming around some attachment points.



There is another product called LizardSkin that has both a sound deadening product and a ceramic heat shield to use against heat, it is available in the new SUMMIT catalog.



The mat is made by Thermo-tec and is called thermoguard FR. It comes in 4' x 8' sheets, the part number for foil on one side TRU-BLIP11406. Foil on both sides TRU-BLIP12406. They are both 5/16" thick. SUMMIT has them, but they are not listed in the paper catalog.



After this procedure was completed, the sound level was MUCH lower, the stereo now sounds good and the a/c will cool the quad-cab truck in our 110+ degree Arizona Dry Heat. Spraying your hood with a sound deadener is a waste of time, that only works if you are going to be standing outside the cab. And who cares at 60-70 mph.



This is a much cheaper way to go for sound deadening and cab heat control than many other similar highly advertised products.

 

[BarryG]

I used some dynomat extreme as well as as a product called brownbread ( B-Quiet sound deadening material ). They are similar. The specs are very close. The dyno is a bit better but not for the additional cost. I removed the door panels and did the inside of the outside skin, the inside of the inside skin and the outside of the inside skin of both front and QC doors. I removed the rear seat and put two layers on the back cab wall. Next was the floor. Removed the seats and the carpet and put two layers on the rear floor and under the seats. Put 3 layers up front and as far up the firewall as I could get. I also put some inside the cowl opening under the hood. Couldnt get much in there as I couldnt get my hands in far, that thing is a cave so some is better than none. It definitely helped but is still not quiet. I did not do the roof maybe I should have. I ended up using 136sf(2 50ft rolls of brownbread and one 36sf box of dynomat) doing all of that. Another item to look at is the ATP wrap that has a blanket for the valve cover and oil pan as well as turbo and exhaust manifold kit. I have not used it but have heard that it is good albeit somewhat expensive.



As a previous poster mentioned there are a couple of real good threads regarding this project. Member LSFARM self proclaimed "noise nazi" has some good stuff posted about what he did. I did not have db meter to do a before and after reading but there was a definite difference in my project but again it is far from quiet. There is a wide variety of products to accomplish the task with just as many price points.

 

[rweis]

I wonder if you could use a noise cancellation device like the Bose systems. Might be cheaper and more effective. Might also cancel the sound system as well though



Bob Weis

 

[DShore]

While at the SEMA show a couple of years ago, I saw a demonstration of LIZARDSKIN ceramic heat insulation. They had an electric hot plate set up in the booth and it was divided into 3 sections. One section was just the bare hot plate, the 2nd section had 1 coat of LIZARDSKIN, the 3rd had 2 coats. They placed an ice cube on each section with the plate turned on approx. 500 degrees. On section #1 the ice cube disappeared within 30 seconds; section #2 it took about 2 min; section #3 took between 4-5 minutes to dissolve. This was timed with my wristwatch, I was impressed. This product is used on many street rods and race cars and is just a little bit thicker than a business card after 2 coats.