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Thread: Hervey’s sound dampening kit? Get from “ken”?

  1. #11
    '82 T3 Turbo FABombjoy's Avatar
    Join Date:  May 2011

    Location:  Lansing, MI

    Posts:    708

    My VIN:    10270

    Butyl tapes are great for killing panel resonance. There is a lot of panel resonance in this car, so this is helpful.

    There is a lot written on the subject of sound dampening / damping / deadening but these are helpful:
    https://www.sounddeadenershowdown.com/products
    https://knowledge.sonicelectronix.co...mpening-guide/

    Exclusively using butyl sheets tapes may not the optimal strategy. Butyl to limit fiberglass panel resonance but use a foam/vinyl combo on top to really block sound. The factory carpet foam with rubber top in the firewall area was on the right track. I rebuilt the "foam triangle" between the fusepanel / ECU tray with carpet pad & dense rubber mat - this matched the height of the original piece. Then installed some closed-cell foam / mass load vinyl along the firewall and the engine noise is noticeably reduced. I'll be pulling the old carpet pad from under the seats and replacing with MLV/CCF, too, so see if further reductions in wind/road noise are possible.
    Luke S :: 10270 :: 82 Grey 5-Speed :: Single Watercooled T3 .60/.48 :: Borla Exhaust :: MSD Ignition :: MS3X Fully SFI Odd-fire EFI :: DevilsOwn Methanol Injection

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  2. #12
    EFI'd dn010's Avatar
    Join Date:  Jul 2011

    Location:  Florida: Pinellas County

    Posts:    1,636

    My VIN:    5003

    Club(s):   (DCF)

    Quote Originally Posted by FABombjoy View Post
    Butyl tapes are great for killing panel resonance. There is a lot of panel resonance in this car, so this is helpful.

    There is a lot written on the subject of sound dampening / damping / deadening but these are helpful:
    https://www.sounddeadenershowdown.com/products
    https://knowledge.sonicelectronix.co...mpening-guide/

    Exclusively using butyl sheets tapes may not the optimal strategy. Butyl to limit fiberglass panel resonance but use a foam/vinyl combo on top to really block sound. The factory carpet foam with rubber top in the firewall area was on the right track. I rebuilt the "foam triangle" between the fusepanel / ECU tray with carpet pad & dense rubber mat - this matched the height of the original piece. Then installed some closed-cell foam / mass load vinyl along the firewall and the engine noise is noticeably reduced. I'll be pulling the old carpet pad from under the seats and replacing with MLV/CCF, too, so see if further reductions in wind/road noise are possible.
    Thanks for posting that, the engine noise is so loud in my car I'm dying to find a way to quiet it down. And to think 15 years ago I actually enjoyed all the noise...
    -----Dan B.

  3. #13
    '82 T3 Turbo FABombjoy's Avatar
    Join Date:  May 2011

    Location:  Lansing, MI

    Posts:    708

    My VIN:    10270

    I do have a "before" recording - I'll try to get an "after" as well.

    Unfortunately the before-recording has the sounds of an open wastegate dump and is on my old tires / wheels. There may be enough cruising for a reasonable comparison. The sound goal is "civilized touring performance" so I've been happy to add some weight in exchange for pleasant long-distance cruising. Having stock manifolds -> turbo -> muffler will almost always be a much quieter than any header setup.

    I have a huge roll of MLV/CCF for the interior. This is the side profile.
    MLV-parcel-blanket.jpg

    A layer cut to fit the rear parcel panel.
    MLV-foam-back-board.jpg

    Old -vs- new engine/trans "triangle" pad under the parcel shelf carpet
    Old-vs-New-Padding.jpg

    The triangle is just this:
    https://www.homedepot.com/p/TrafficM...0113/301153300
    contact cemented to:
    https://www.homedepot.com/p/StepAhea...8-33/202616234

    And then another layer of MLV/CCF cut to the same size as the loose parcel carpet over top.

    The hollow areas behind the parcel are also stuffed with odds and ends of loose carpet foam

    I could have used MLV/CCF exclusively for the triangle pad, but I tend to use the parcel area a lot. With the amount of foam needed to level-out the surface relative to the ECU and fuse covers I was concerned about heavy items causing a Tempur-Pedic effect and leaving dents/divots in the surface
    Luke S :: 10270 :: 82 Grey 5-Speed :: Single Watercooled T3 .60/.48 :: Borla Exhaust :: MSD Ignition :: MS3X Fully SFI Odd-fire EFI :: DevilsOwn Methanol Injection

    Console5.com - Game console parts, kits, games and more. [shop] [wiki] [RSS] [f] [t]

  4. #14
    Delorean Guru
    Join Date:  May 2011

    Location:  Northern NJ

    Posts:    6,781

    My VIN:    10757

    Club(s):   (DMA)

    One way to install sound deadening is to use strips of the rubber to add mass to the panel so it won't resonate. Cover with closed cell foam. Could take some experimentation to get it optimized but you can wind up with a better, cheaper job with less weight. You should also use metal foil to help insulate and reduce thermal conduction. As long as you are dong this, anything you can do to help the A/C is a good thing! Make sure any openings are well sealed so sound can't get in easily. If the motor is very noisy maybe you need exhaust manifold gaskets?
    David Teitelbaum

  5. #15
    Senior Member
    Join Date:  Aug 2015

    Location:  Novi, MI

    Posts:    234

    My VIN:    4665

    Agreed on doing some heat reduction work while you are at it. I found this site which has some interesting solutions for our heat challenges.

    Have not used any of their products, but seriously thinking about it.

    https://www.heatshieldproducts.com/automotive

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