taming the beast - making it more liveable

[Aernan]

My wife and I took our first freeway drive in our new LMTV. It involved climbing into the local hills to our favorite burger joint at Alice's Restaurant.

If you are the only one driving the truck it's a bit bumpy and loud. When my wife is in the truck and we are trying to talk to talk with each other if you talk loud it mostly works. When she was standing on the passenger's side with the door open should could not understand me. The seats are like boards. I'm sure the foam is hardened over the years.

I have seen posts about adding sound deadening materials. How quiet can I make the cab? Are there any tricks for silencing the engine?

The bumps. Our cab air ride seems to work but is dumping air on the passenger's side. The CTIS works and I have been driving in hwy mode. At speed it seems to be fine but surprisingly at 30 mph on some surface streets the truck really bounces and bucks. If I add air ride seats how much will it calm the bumps?

 

[Aernan]

My wife and I took our first freeway drive in our new LMTV. It involved climbing into the local hills to our favorite burger joint at Alice's Restaurant.

If you are the only one driving the truck it's a bit bumpy and loud. When my wife is in the truck and we are trying to talk to talk with each other if you talk loud it mostly works. When she was standing on the passenger's side with the door open should could not understand me. The seats are like boards. I'm sure the foam is hardened over the years.

I have seen posts about adding sound deadening materials. How quiet can I make the cab? Are there any tricks for silencing the engine?

The bumps. Our cab air ride seems to work but is dumping air on the passenger's side. The CTIS works and I have been driving in hwy mode. At speed it seems to be fine but surprisingly at 30 mph on some surface streets the truck really bounces and bucks. If I add air ride seats how much will it calm the bumps?

Could the shocks be worn out due to age?

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[Givinup]

I'm in the process of sound deadening and insulating the cab. I've painted it with a sound deadening and thermal paint. Next I'll put dynamat, then mass loaded foam, carpet, then a suede headliner to soak up more sound. Putting the same thermal paint above the engine, as well as high heat dynamat and a thermal blanket.

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[coachgeo]

I'm in the process of sound deadening and insulating the cab. I've painted it with a sound deadening and thermal paint. Next I'll put dynamat, then mass loaded foam, carpet, then a suede headliner to soak up more sound. Putting the same thermal paint above the engine, as well as high heat dynamat and a thermal blanket. ...

What products did you choose to use?

 

[Givinup]

What products did you choose to use?

I'll add pictures and product names tonight. I'm using tapatalk and it won't let me upload pictures or links without a tapatalk account instead of the forum account.

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[Aernan]

I'm in the process of sound deadening and insulating the cab. I've painted it with a sound deadening and thermal paint. Next I'll put dynamat, then mass loaded foam, carpet, then a suede headliner to soak up more sound. Putting the same thermal paint above the engine, as well as high heat dynamat and a thermal blanket.

What is the combination thermal noise paint. Is this some kind of bedliner material or something more like undercarriage paint/coating?

 

[Aernan]

Now that I have had a night sleep on it here are my ideas of areas/things that me be possible to reduce overall noise:

Engine:
- tune engine to reduce overall noise.
- wrap intake/exhaust pipes with exhaust wrap or aerogel cover
- acoustic cover over valve cover?
I know most passenger cars have a plastic cover that is lined in foam to reduce the noise. I don't think there is space to do this.

Cab:
- under cab:
a. thermal blanket
b. spray underbody coating
c. bed liner
- Doors
a. dynamat
b. acoustic foam
c. custom door panels not made from metal
d. fill voids with expanding foam (area above the window)
- Floor
a. acoustic/thermal foam
b. carpet
c. dynamat
- Walls
a. same as doors
- Ceiling
a. all the above
b. acoustic deadening shape. (see discussion bellow)
c. soft materials as face

Radical Ideas
- active noise cancelling speaker

 

[DiverDarrell]

I think if you dynamat the interior and doors you will see great improvement. It will never be bmw quiet without ear plugs. I have added sound mat to my doors, next up will be the cab and roof. Currently my wife and I just do ear plugs for long rides. Overall it’s only a little louder than my Jeep with the soft top. One way you can cut the road noise is to put road tires on it.

 

[Aernan]

I think if you dynamat the interior and doors you will see great improvement. It will never be bmw quiet without ear plugs. I have added sound mat to my doors, next up will be the cab and roof. Currently my wife and I just do ear plugs for long rides. Overall it’s only a little louder than my Jeep with the soft top. One way you can cut the road noise is to put road tires on it.

I totally agree about road noise and tires. I will look into other options.

From what others have said the dynamat will deaden thuds but won't do a great job of damping sound. Some people have recommended using acoustic foam to help absorb more of the noise.

 

[Aernan]

I noticed there is a vent that goes from the bottom of the cab directly above the engine. I think a lot of sound is bleeding through that vent hole and the open grate. Has anyone looked into damping that sound at all?

 

[Awesomeness]

I noticed there is a vent that goes from the bottom of the cab directly above the engine. I think a lot of sound is bleeding through that vent hole and the open grate. Has anyone looked into damping that sound at all?

Have picture? My cab has no holes in the curved part of the bottom of the cab that I will call the "engine tunnel" (except for the 4 bolt holes for the center seat and the two bolt holes on each side for seat belts, all of which are populated).

 

[dmetalmiki]

Interesting..I thought those 'modern' styer type trucks were reasonably quiet. My 5ton M54A2 whistler is quite tolerable sound wise in the cab, and a passenger chat is quite do-able.
I 'insulated' the cab floor (all) with Lead sheet. Then thick underlay. The roof was insulated with foam. Under the bonnet there is a thick sheet of fireproof underlay..Which does cover the firewall inside and out.

 

[coachgeo]

Interesting..I thought those 'modern' styer type trucks were reasonably quiet. My 5ton M54A2 whistler is quite tolerable sound wise in the cab, and a passenger chat is quite do-able....

5ton engine is out if front with a fire/sound break between and places for sound to go besides into the cab ...... the Cab over FMTV world has engine right under our arm pits with a tunnel that mostly traps the heat and sound leaving it to permeate into the cab.

 

[Aernan]

Have picture? My cab has no holes in the curved part of the bottom of the cab that I will call the "engine tunnel" (except for the 4 bolt holes for the center seat and the two bolt holes on each side for seat belts, all of which are populated).

When I tilt my cab near the front of the truck above the radiator there is a huge flap door. It looks like it brings in fresh air.

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[Aernan]

Here is where the vent is located

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[Awesomeness]

Here is where the vent is located

Ok, yes, I have that vent (obviously). Of interest to you though, my truck has a rubber gasket around the top of that area, attached to that piece of flange with the holes in it in your picture (near that vent).

 

[rocket990]

I think that is the air intake to the heater.

 

[coachgeo]

Here is where the vent is located

Can you back up some and take that pic. t's a good pic of the vent...... but not enough reference points to suggest where on the cab that vent is beyond that it's near a large hump and everything is green. Thank you in Advance.

 

[Awesomeness]

Can you back up some and take that pic. t's a good pic of the vent...... but not enough reference points to suggest where on the cab that vent is beyond that it's near a large hump and everything is green. Thank you in Advance.

He's basically taking the picture facing forward, resting his hands on the radiator (which is the black thing at the bottom of the picture). The vent is into the bottom of the heater box on the dash, and the hoses on the left side are the heater hoses going into the heater box. The cab is tipped forward, so all that green area would be laying down in its natural state. The four silver bolts at the top of the picture look like they are through the "ditch" on the engine tunnel, between heater and the raised platform area where the middle seat is - I don't think those are stock.

 

[snowtrac nome]

That is the outside air intake for the heater. I drive mine on a daily basis here are the noise I notice when the truck starts you here the cat purr at idle, turn the heater on high you can no longer here the cat. Accelerate down the road the turbo whistles, barely noticeable over the heater on high, more noticeable with it on low. Once you get to highway speeds the most noticeable noise is tire noise, and it will drown out everything but the heater , if I drop to say 30 things get real quiet again. The cab on mine has no liner its one big echo chamber I think the best thing I could do is line it with some acustic insulation foam, I suspect it would be real quiet then, I'm also thinking about a spray on product called lizard skin for the bottom of the cab and fender wells