Noise Reduction

[browerw]

Thank you all for the great info!! Those of you who have pictures and other interesting info send it to me e-mail I like to see the results.

 

[Lsfarm]

Thanks for that link

HEMIDart: thanks for that link, it was good reading. I have one comment though: if my truck idled with dB levels in the low 60's, I would never have started on 'Operation Quiet Cummins'. The truck in the article is VERY quiet to start with.



I'm sure the readings are for real, because the engine readings are very close to the dB levels I get from my readings of stock trucks. I just am very envious of having stock readings in the cab that low!



Oh well, maybe Chrylser left out part of the firewall on my truck and covered the hole with duct tape.







I'm real glad to have quieted my in cab dB readings down to the low 70's and high 60's at idle.



I agree, the ATP items are expensive, and they don't address the road noise coming through the firewall, floor and back wall of the cab.



So far my total expenses are less than half the cost of the ATP items, but I have put a lot of time in on the project. Of course, that's part of the fun.



Greg L

 

[RedRamer]

Lsfarm

that's for both sheets - heavy - 128lbs so shipping is costly.

I also would like to know where to best to insulate is.

I know goig down the hwy I'm getting this drone comming for the back so that's why I got the lead. Back of xtcab and floor should help.

but the front is where the rear noise is comming from and shure would be nice to cut down the noise without killing thatbeutifull Cummins misuc.

I;'m thinking as high as I can go on the inside firewall, hanging the lead on the inside door panels.

but engine compartment looks like a bit$h of a job.

Lsfarm - did covering the oil pan and the P7100 help with inside noise at all?

I really don't give a darn about the outside noise!

thanks

 

[Lsfarm]

Using your lead sheeting

Hi Goober, I think that the most effective place to use the lead sheet you described would be to insulate the floor and the back wall of the cab.



At least in these two places the lead sheeting will be easy to apply. I'd just pull back the carpeting and lay the sheet down. Then for the back wall I'd install a layer of either a Dynamat type product or a layer of iceshield. And then glue the lead sheet to the first layer.



I've never had a door panel off of a Dodge truck, so I don't know how difficult it will be to put a sheet of lead behind the panel.



I hope the lead sheeting works for you.



Greg L

 

[RedRamer]

Thanks for the help - will let you know in about a month.

meantime I'm looking to borrow a db monitor to see the effect.

 

[Lsfarm]

Lead Sheeting

Well I've decided to try some of the lead sheet that Goober is going to use.



I ordered two sheets, and plan on using them on the floor and back wall of the cab. If I have enough left over, I will try some in the engine compartment too.



I'm hoping to reduce the exhaust resonance from a drone to a distant hum.



I'll post the results when I get the work completed.



Greg L

 

[WaynesWorld]

lead lined

Does it seem a little wierd, some are taking off thier muffs, & others are trying to make thiers quieter? What a great big wonderful world!

Does the lead lining keep Supermans x-ray vision out? How does this affect Smokies heat sensors?

Questions you were afraid to ask?



WAYNES WORLD

 

[CCahill]

I'm hoping to reduce the exhaust resonance from a drone to a distant hum

Another reason I've kept my stock exhaust..... Although, I'm running out of reasons...



Colin

 

[Lsfarm]

Exhaust noise

Colin, I am pushing too much power to stay with the stock muffler. But I may do a swap back to the factory system just to see what the dB meter tells me about the 'drone' .



I would be educational to see the effect on my EGTs as well.



I may find time this week for this experiment.



I'll post the results if I try the swap.



Greg L

 

[Turbo Terry]

To loud? WHAT ? Sorry I had to do it

 

[CCahill]

Greg... I totally understand... I'm running II's, and a comp now, and I'm sure I would make more power with an exhaust thats less restrictive... . But after reading most of the posts on exhaust, it seems like the majority have droning problems, mostly when the resonator is removed... . But like I say... . I'm running out of reasons...



Colin