Successful sound deadening for headers?

[ls1frc]

Hey all, I am enjoying my 6.2 swap very much. One thing that is really starting to get on my nerves is the header "tinny/airflow" sound you hear constantly in the cabin. It wasn't as bad on my 5.3 because of the lower lift cam and smaller engine. But on the 6.2 it is starting to irk me. Basically makes the engine sound like a junker as you accelerate lightly. Still sounds amazing at WOT though.

I have a lot of experience with headers on my previous cars and never had this sound, I think it's just the way the pipes have a sharp bend off the driver side header as it goes into the y-pipe, so you can actually hear the airflow.

I was considering pulling the seats and carpet and added some insulation to the floorboards and firewall area. Do you think this would make a difference? I also saw dynamat has a hoodliner as well.

Can anyone point me in the right direction of which material to buy?

TL;DR, trying to reduce valvetrain/header noise in the cabin.

 

[mikeyss]

The firewall has a thick pad already, but it ends just under the gas and brake pedals. After that is just a small layer of jute attached to the carpet. If you add deadening to that area as well as inside the door skins, most of the noise is gone.

 

[ls1frc]

Ok the y-pipe connection is right in that area that has no padding. Must be it. I will give it a shot.

 

[FrankU]

Coat the headers with Swain coating.....worked for me.

 

[ls1frc]

Researched for several hours. For pure sound blocking, you want mass loaded vinyl on top of closed cell foam. You can buy them as raw materials and try to combine them, but screw that. So I just spent the money and bought Second Skin Audio Luxury Liner Pro, which has the MLV on top of the closed cell foam already for easy installation.

I will do as high up the firewall as I can without removing dash and do as far back towards the seats as I can. Will report back results once done.

 

[ls1frc]

Coat the headers with Swain coating.....worked for me.

Did you have a before/after comparison? I may do this as well.

 

[ls1frc]

Also during my research, it was suggested that Noico sound deadener is just as good as the Dynamat at a fraction of the cost. I bought some squares and will lay that down underneath the vinyl layer.

https://www.amazon.com/Noico-deaden...dchild=1&keywords=noico&qid=1616945898&sr=8-3

 

[91RS]

Also during my research, it was suggested that Noico sound deadener is just as good as the Dynamat at a fraction of the cost. I bought some squares and will lay that down underneath the vinyl layer.

https://www.amazon.com/Noico-deaden...dchild=1&keywords=noico&qid=1616945898&sr=8-3

It is most definitely not. The best sound deadener you can buy right now is Resonix. Second place goes to Dynamat Xtreme. Other than those two, don’t bother.

 

[FrankU]

Did you have a before/after comparison? I may do this as well.

No comparison sorry. I've been Swain coating my headers on various cars & trucks since the 80's. I swear by it for noise and heat.

 

[petethepug]

CCF/closed cell foam. The stuff you find in egg crate type shipping boxes rates at the top. All the stuff mentioned here will get you where you need to be.

I run a German made supercharger, a g lader, or a lysholm on a tiny 1.9L motor in our 90’s era VW. I don’t run headers simply because the motor jumps around too much and breaks all the welds.

That specific tinning sound was present in this tiny VW motor from the increased flow, lightweight internals and aggressive cam. Ceramic coating the exh mani & down piping cut the tinning sound way down and, as a more important benefit, it cut the under hood temps down by at least 100*

Again, a combo of anything mentioned will be a win. In our VW, running Hushmat in the firewall, roof and floor, CCF in the rear wheel wells (just crammed in) and ceramic coating the exhaust components completely transformed the car into a Lexus quiet ride.


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