E350 Interior noise and steering?

[iggi]

Just back from a longer trip.. Still too dang loud.
According to my uncalibrated app, I'm averaging mid 70's dB which is a good improvement over before but after a 4 hour drive I'm exhausted and my girlfriend says her ears are ringing. It's honestly too loud to have easy conversations at highway speed.

According to the sound meter most of the noise is transferring through the engine cover and the floor area by the passenger's feet. I'll be adding a couple more layers to all the offending areas.
Feels like -5dB will make it tolerable and -10dB will make it enjoyable.

 

[iggi]

3rd round of sound proofing done.

Pulled the engine cover again.. Put a layer of the Noico 80 mil Sound deadening mat over the entire exterior plus double on the passenger side corner and middle which seemed to transfer the most noise.
Then a layer of the Noice Green 170 mil Waterproof Sound Insulation and temperature mat.
Added another layer of the butyl in the passenger footwell area and floor closest to the engine compartment, then a layer of the foam sound insulation over that.

Results.. not as dramatic as I hoped but still good.
Dropped about 5 dB off the average. Cruising speed is now about 71 dB. Engine at idle down hills is 66-67. It's actually eerily quiet when coasting down hill.
Feels like we can now have a reasonable conversation without shouting. Before this we tended to not talk much as highway speeds due to the noise.

Something to consider depending on who you travel with and how much you like talking. Spend too much on sound proofing and you might be missing your "quiet" time. lol.

The foam on the outside doesn't look bad but.. it's not durable at all so the final step will be to either buy or make some sort of cover for the engine cover.

 

[Bikersmurf]

I’m glad you’re making progress.

Random thoughts... I’ve noticed the noise / engine noise probably triples if the windows are open much. It came with wind deflectors which do help a lot, but if the window is half way down, forget easy conversation.

Which leads me to wonder if door &/or window seals would make a difference. And if sound proofing the front doors would also reduce reverb.

As I mentioned... random thoughts, I’d like to see you getting readings of 50 dB.

I’ve also read, in one thread on here, that wrapping down-pipe with header wrap, and making cover for the turbo also did.

 

[iggi]

Thanks! Even 60 dB would be amazing!
I hadn't even thought of header wrap on the turbo and pipes. Doh. Great idea!
I'll pursue that next.

I also think some sound insulation in the doors would help overall and be easy to do.
I popped out the side step covers and the bit that I added there helped for sure.

I’m glad you’re making progress.

Random thoughts... I’ve noticed the noise / engine noise probably triples if the windows are open much. It came with wind deflectors which do help a lot, but if the window is half way down, forget easy conversation.

Which leads me to wonder if door &/or window seals would make a difference. And if sound proofing the front doors would also reduce reverb.

As I mentioned... random thoughts, I’d like to see you getting readings of 50 dB.

I’ve also read, in one thread on here, that wrapping down-pipe with header wrap, and making cover for the turbo also did.

 

[luthj]

In the dark, use a bright light to look for tiny gaps along the doghhouse seal. Even a few tiny holes can let huge amounts of noise through.

My preference would be to wrap the doghouse in as thick a layer of medium-soft foam as you can accommodate. (3/4" would be ideal) Then cover that with a layer of 1/8" mass loaded vinyl. Seal all the seams in the vinyl where the pieces meet, to form a continuous shield. Lower density neoprene is cheap and works quite well (think gym mats). Putting a similar layer of neoprene under the floor mats helps as well.

On top of the MLV a layer of sound absorbing material such as thinsulate helps to attenuate the high frequencies that pass through the vinyl.

Mass loaded products don't have much value on curved surfaces like the doghouse (when applied directly). They need a decoupling layer to help block sound.

I am not familiar with the dash vent system on the E series. But if there are ducts exposed to the engine compartment, they can allow lots of noise into the cabin. In those cases insulated the ducts can help.

Mcmaster carr has some nice products that may work. Urethane coated foam for example.

https://www.mcmaster.com/#sound-control-insulation/=7f41f08066be476a976efc14a36e1ef1jxt8optj
https://www.mcmaster.com/#sound-control-insulation/=7f41f08066be476a976efc14a36e1ef1jxt8owjq

 

[iggi]

Resurrecting this with an update. Never did add any more soundproofing. Would be nice to be a bit quieter but too busy with other stuff to bother.
A few days ago it occurred to me I hadn't added any cetane booster to my fuel in a while. As I was just getting set to change the oil and I use Archoil anti-stiction additive I added some of their fuel additive to the order.
Last night as I fired the rig up I thought to myself.. "hmmm.. that sounds smoother and quieter"
Today I fired up the sound measuring app I used last year to check. 55 dB at idle. Had to come to this post to check my numbers. Looks like I didn't record an actual idle but I did check the sound while rolling down a hill nearby. Last year it was 66-67 dB. Today I got 58 dB.

Obviously this is just an app on a phone and possibly not very accurate but it essentially confirms what my ears told me. It is quieter. Which surprises me all to heck.

No affiliation with these guys. But for Canadians they were fast with the shipping and had a better price than Amazon.

Archoil Complex Fuel Modification AR6200

Shop Archoil 6200 Diesel Fuel Additives with Dirty Diesel Customs. Save Duty and Brokerage, Shop Canadian!

www.dirtydieselcustom.ca

 

[iggi]

Did the cab ceiling a couple days ago. No reduction in the at idle sound levels but better at highway cruise. Seems mostly to dampen the booming when hitting bumps and such and reducing wind noise.

 

[cjken]

Archoil worked really well in my 7.3. Surprisingly quieter and smoother running it.
I never really believed much in additives until archoil.

 

[cjken]

Did the cab ceiling a couple days ago. No reduction in the at idle sound levels but better at highway cruise. Seems mostly to dampen the booming when hitting bumps and such and reducing wind noise.

I’m going to sound deaden the cab of my Duramax c4500 this week. It’s pretty quiet now, but since I have the cab apart I figure it can’t hurt!

 

[iggi]

Pretty quick to do and while not a huge difference it seemed to take the 'edge' of the noise. 100% recommend.

I’m going to sound deaden the cab of my Duramax c4500 this week. It’s pretty quiet now, but since I have the cab apart I figure it can’t hurt!

 

[sloroads]

I have another 1999 7.3L and it is way quieter. But its all factory equipment and carpet inside and the regular exhaust. I'll check the rest of the boots going through the fire wall. Can someone get me some pictures of how the dog house seals fit? Or better yet a short video. In the attached image I show the dog house seal what goes between the two seals?

Did anyone ever figure this out?

 

[86scotty]

Did anyone ever figure this out?

Yes, bought a V10 van.