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ncc74656

engine/exaust noise

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what are peoples go to's for damping exhaust noise and engine/valve train noise? i have already done the firewall and trans tunnel but I'm also looking to mute things at the source a bit. the high temp of the engine bay is the hurdle i think. id also like to do something to keep the heat from the manifolds, turbos, and exaust from anything else.

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Have you deadened the floor or doors at all?

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the truck is still appart but yea i plan to do that, i have done a frame up rebuild on this guy. i used cascade audio spray on dampner on the wheel wells and firewall, used their VB4 lead damper on the trans tunnel and up the center of the firewall, and their 3/4" MLV products from bottom of windshield to under foot. i plan to do this type of deadening all the way through the cab, rear wall, and roof.

 

ive seen exaust wraps but they don't seem to keep the heat in as well as i would like (compared to blankets) and idk how their acoustic properties are (if any consideration is given at all to them).

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I’m old school. I like to hear my pipes !!! Music to my ears !!!

just saying

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Spray on stuff is not really effective at hardly anything.  3/4" thick MLV ought to be ridiculous heavy and good...but I've never seen that.

To stop sound you need mass.  To stop panels from making sound you need energy absorption.  To stop transmission of sound from one spot to another cannot be generalized, nor is it easy.  That I make a ton of money on each and every year off all the OE's helping them to optimize.  Just the measurements alone to get there though are well over $10k.

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yea idk if I'm up for a 10K measurement but i am trying to do what i can. i really like the spray on because i think its easier to install and ive been told its about equally effective compared to the stick on. i spray it on 1 thin layer at a time and go to about 1/8 - 3/16" thick.  i then use 1/4" closed cell foam with lead in the center over the high noise areas. then i used this arcryllic/ceramic vinal that's 3/4". ive never used this company before but i heard good things and they seem to supply all the factory damping for mercies, bmw, the germans...

i also put my factory barrier over this so i have 1.75" thick of damping material from the bottom of the windshield to the start of the seats.

 

i enjoy the sound as well and i will still be able to hear it I'm sure, i have compound turbos on a diesel with next to no exaust on it. but I'm trying to get a lower sound floor to make my dynamic range and music sound better. i also don't want wind noise coming in either.

 

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Nearly 2" of damping?  Are you fucking serious??  

The spray on is nearly useless in comparison.  Don't bother.

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lol! go big or go home right? no i stripped the truck and put a new body on it due to rust so when i put it back together i wanted to try out this cascade audio stuff, never used it and just want to know how good it is. i ordered up all the stuff and ive got a gallon of spray left so I'm still going to use it, at the very least its hypophobic so it will help seal the inside of the cab from water and such (not rated for external so I'm using linex there) but yea, I'm filling every opening and area with expanding foam (the stuff used for doors and windows, not the great stuff) and then I'm adding thick rubber deflectors inside the fenders to deflect wind down and up instead of directly into the door jam so i hope to eliminate all the wind noise.

 

i plan to use some turbo and valve cover blankets but then i also want to wrap the exaust manifold and pipes going back to keep heat away from the cab and other parts and also to eliminate rattles and such. given its a diesel ill never get it quiet and that's not my goal, i just want the engine sound to be smoother and in the cab a bit quieter. trouble is my EGT's easily peg 1500F when I'm hammering it, 1200F sustained while heavy towing and 650F cruise so finding sound absorption materials for under hood is a challenge

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All that product and you are still having noise issues??? Did you do complete coverage on the floor with your barrier layers (MLV)? Vibration dampeners offer minimal help with air borne noises like diesel, exhaust, and turbos...you need blockers and barrier layers. If you have gaps it will still let sound through. With 1.75" of the right material on your floor, you should not be having sound issues.   

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He doesn't have 2 inches of blocker on the floor.  If so the installation is the most idiotic of all time.

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