LOUD E350 interior

[HumboldtSeaBilly]

So I have a 2001 E350 cargo van (7.3L powerstroke diesel) with 3 layers of reflectix covering the whole interior. Any plastic you could take off I did and put insulation behind it. Also, there is insulation on the floorboards, with 1/2" rubber horse mat and 3/4" plywood. I added reflectix above the cab and stuffed some down the a pillars as well. This sucker is still LOUD inside. Like driving down the highway at 70 you have to CRANK the radio to overcome the wind noise/engine. Most the time on long drives I wear hearing protection, otherwise, I am exhausted from the road noise. My pops has a 1999 and is much much quieter than mine, much quieter.

I do have different (more square roof racks) than him, but just even his engine is much quieter than mine, and his cab noise is much quieter.

Do you guys have suggestions as how to reduce the interior noise? I was thinking some of the sound deadening material, and possible one of those acousti-shield windshields.

I have zero engine mod's and a stock exhaust.

Thanks for any tips.

 

[Bbasso]

Are you sure the dog house is seated properly?

And if you have plans for an interior build, it will help to reduce the sounds levels.
I have a 4 inch turbo back exhaust and unless I'm mashing the pedal it's rather quiet because of the insulation (similar to yours) and all the interior items.

 

[philos]

You'll need multiple types of materials to combat all the different types of road noise. In addition to reflectix, I use ensolite, harbor freight neoprene flooring, and foil-backed jute/felt. Also, butyl sound dampening sheets under all that stuff.
Insulate your dog house too; remove the ****e factory insulation and put good stuff down. Also, make certain that it's sealing properly to the floor.



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[ohpyramids]

I feel you man. I have the same rig and it's rough. My front of cab is still super loud, I haven't addressed it yet, but everything behind the seats is silent.

I went with roadkill and covered 1/3 of each panel and fully covered the wheel wells. Then got some of the thinsulate insulation from Hein and covered the doors and walls with that. Then got closed cell foam and 3/4" plywood on the floor.

I had a Subaru with a noisy roof rack. Several things helped: finding ways to disturb or smooth out airflow offer the pipes- like a front deflector or changing the shape of the pipes with foam and zip ties. Also insulating the roof helped.

Would be super interested to know what everyone is doing to address noise out of the doghouse. New rubber gasket? What high temp insulation is good?

 

[djbonsu]

I plan on going with a raamat/ensolite combo throughout the van except for the floor as I'll Por-15 the entire floor before adding the insulation and thinking about going with a bedrug or the harbor freight neoprene flooring that philos suggested. Haven't decided on the final finishes of the walls yet. Also will add some Home Depot "peel n seal" to te dog house and seal the edges with HVAC foil tape. I too have a LOUD interior and hope this will combat a majority of the 7.3 engine and road noise.

 

[pugslyyy]

I plan on going with a raamat/ensolite combo throughout the van except for the floor as I'll Por-15 the entire floor before adding the insulation and thinking about going with a bedrug or the harbor freight neoprene flooring that philos suggested. Haven't decided on the final finishes of the walls yet. Also will add some Home Depot "peel n seal" to te dog house and seal the edges with HVAC foil tape. I too have a LOUD interior and hope this will combat a majority of the 7.3 engine and road noise.

It's hard to quiet down a 7.3. After driving one cross country I was hearing it in my sleep for a couple of days.

 

[IdaSHO]

Certainly not the quietest engines. :sombrero:


Ive found the absolute most effective way to quiet the motor is to regear to a higher gear, or simply slow down to get the revs down.

Regearing from 4:10s to 3:55s reduced the in can noise a ton on my F-series.

Its a pleasure to drive now. Makes the truck seem 1/2 its age.

 

[luthj]

Closed cell foam covered by Mass Loaded Vinyl on the floor (and on the doghouse/firewall where possible) will make a noticeable difference. Neoprene foam sheets are fairly inexpensive, won't absorb water, and are easy to work with. Higher density polyethylene foam works too. There are products with MLV bonded to foam available. I think Mcmaster carr has some, but they are not cheap. Mass blocks the sound. Absorption materials (such as thinsulate) will help catch any that gets through.

Stuffing some thinsulate, rockwool, etc behind the dash will help as well. On any large panels without bends, putting some constrained layer damper such as fatmat will help. Only 25% coverage is necessary.

I would guess doing all of the above will drop dB levels by 10dB or more. Of course if your doghouse is not sealed correctly (or you have holes, gaps in the firewall) nothing will help.

 

[djbonsu]

It's hard to quiet down a 7.3. After driving one cross country I was hearing it in my sleep for a couple of days.

LOL I will say it isnt that bad but then again I am around LOUD music alot

Certainly not the quietest engines. :sombrero:


Ive found the absolute most effective way to quiet the motor is to regear to a higher gear, or simply slow down to get the revs down.

Regearing from 4:10s to 3:55s reduced the in can noise a ton on my F-series.

Its a pleasure to drive now. Makes the truck seem 1/2 its age.

Ha! and hear i am doing the exact opposite! Sigh....

 

[Eric3187]

i had a 6.0 van, sprayed lizard skin ceramic insulation / sound deadening over the whole floor section, inside the dog house and up the side walls about 6" then installed a BedRug brand carpet/padding, it was extremely quiet inside.

you can do a DIY version of lizard skin if you google it, end up being about $100 instead of $400+

 

[IdaSHO]

Ha! and hear i am doing the exact opposite! Sigh....

Huh?

Unless you are towing heavy often, the 7.3 loves tall gears.


What gears do you have now? Why are you gearing down?

If you are not chipped yet, Id chip it then consider gears.

 

[Ozrockrat]

Wrap the up and down pipes and get an insulation blanket for the turbo. Will help with the annoying turbo whine and also reduce heat. Then as the other guys said. Insulate the crap out of it.

Then never buy a Freightliner. They are definitely worse.

 

[djbonsu]

Huh?

Unless you are towing heavy often, the 7.3 loves tall gears.


What gears do you have now? Why are you gearing down?

If you are not chipped yet, Id chip it then consider gears.

I went from stock tire size to 35s after UJOR 4x4 conversion. My front diff has 4.10 so Im swapping the rear to match. I have a dp tuner as well

 

[IdaSHO]

Gotcha, well the 35's + 4:10s should do you just fine.

And swapping out the rear gives you the option to toss in a locker at the same time:ylsmoke:

 

[Bikersmurf]

It's odd your's is so much louder. Mine's not too bad with zero sound proofing in the cab. The floor in the back is 1"+ and the box is built like a tank... Insulated walls, doors, and ceiling. I did find it smoother and quieter after changing the LSD diff oil and adding additive. When the doghouse wasn't seated right it was much louder. Can barely hear the turbo unless headed up the ski hill.

What type of tires are you running? Is it quieter without the racks? Are you hearing diesel rattle? Turbo whine?