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Sound deadening?

Discussion in 'General Mustang Discussion' started by RapidRabbit, Mar 31, 2017.

  1. RapidRabbit

    RapidRabbit Well-Known Member

    Quick question

    I'm looking for sound deadening. I'm not doing the whole car or looking to quiet the overall ride. It's a convertible so it's noisy anyway.

    What I want is a budget friendly, but decent material. I am looking to do under backseat, some of the trunk floor and maybe a small patch inside the doors.

    The main reason is the fuel pump is super loud when stopped. I don't hear it when cruising. But my daughter won't ride in my car because it's too loud in the backseat. And if u drive with the top up it rattles the car.

    Any suggestions? And maybe how many sqft I'd need for those areas?

  2. JeffTepper

    JeffTepper Well-Known Member

    It might be easier to switch to a mechanical pump or a quieter electric pump.

    Sound dampening that works is usually a combination of several products that together isolate, deflect, and absorb sound waves. A comprehensive system can run into some real $$$ but if the cheap $hit doesn't do it for you, you do have options. Here is a system that I am about to use in a project car that has a serious sound issue: www.sounddeadenershowdown.com
  3. RapidRabbit

    RapidRabbit Well-Known Member

    I am running EFI so electric pump is necessary. When this one does I will get a quieter one for sure. I'm really just looking to soften the noise. It's just producing a sorry of tinny vibration.
  4. Horseplay

    Horseplay Well-Known Member

    I used Dynamat almost exclusively. For some additional, unplanned pieces I bought some RAAMat. I liked the Dynamat better due to no reason other than to me it felt "better" and seemed to conform and adhere better but both test well if you waste time researching such stuff. I have always preached against buying the HomeDepot stuff simply because it was not made for automotive applications. Just because some redneck says it stuck good and worked doesn't do it for me. I work in an industry where, for example, we make literally hundreds of different types of masking tape. We do it because certain applications require nuances to the basic concept. I won;t even get into the discussion of adhesives. So I buy a product made to do what i want it to do in a case like this one. So there!
  5. kb3

    kb3 Well-Known Member

    I would echo all of Terry's comments, with the exception that I use Second Skin Audio products. While neither this or Dynamat are reasonably priced, they both do a great job at quieting down the car. I used the mat on the floor, in the doors and on the ceiling. I also used their luxury liner below the carpet. I can't hear the fuel pump, or much in the way of road vibrations.
  6. RapidRabbit

    RapidRabbit Well-Known Member

    I definitely want to avoid l the home Depot stuff. I'm not trying to go that cheap. Depending on how much I need I've been looking at raamat & dynamat . Both seem priced similar. But there are some many Breanna out there. I just wanted to see what feel everybody got.

    Do you guys think 25 or 50 sqft for what I'm doing would be enough? I can always order more I guess. I'd like to keep it under $100 maybe.
  7. kb3

    kb3 Well-Known Member

    I would think the 25 sqft would do the backseat/trunk area. As for the doors, you really only need to put in a few 4-6" wide strips to calm down the vibration and make them sound much better upon closing.
    RapidRabbit likes this.
  8. RapidRabbit

    RapidRabbit Well-Known Member

    Well maybe I'll order 25 to start and see where I end up. I can always do the doors later. Or if I have scrap left over.

    I've got a couple days off next week and I'd like to get everything buttoned back up and put some miles on the beast.
  9. Midlife

    Midlife Well-Known Member Staff Member Moderator

    Buy some good quality ear muffs and ear plugs.
  10. JeffTepper

    JeffTepper Well-Known Member

    A different approach might involve isolating the fuel pump by mounting it on rubber insulators and box the whole thing in with an enclosure lined in mass loaded vinyl (MLV)
  11. Mach1 Driver

    Mach1 Driver Active Member

    I suggest you go to SecondSkinAudio.com and check out the video. This cat claims that most noise is generated in the wheel wells and has spray on deadeners for that area and matt for others. Another good site is sounddeadenershowdown.com. It will tell you how much of various products are needed for 1st generation cars, but their total comes to a whopping $725.
  12. KBMWRS

    KBMWRS What did the moron say today?

    I used 2nd Skin also. Make sure and get a small wooden roller and be careful not to cut up your hands.
  13. Horseplay

    Horseplay Well-Known Member

    Just to add on...

    You don't need to cover every square inch of a panel to get good effect. It doesn't hurt but not absolutely necessary. Layering of different materials helps as well. Longer term, ditch your current fuel tank and go to an in-tank pump set-up for maximum noise control. It also helps the pump as the fuel keeps it cool. I'm sure your current pump is mounted with rubber to isolate the vibration. Make a bracket that mounts to the car with isolation material and then mount the pump to the bracket with a second round of rubber washers. It does make some difference but external pumps are loud regardless. Be careful if you try to make an enclosure for the pump as they get hot pretty easily and the heat can kill them.
  14. RapidRabbit

    RapidRabbit Well-Known Member

    The pump is mounted with rubber isolaters on a drop bracket. I may look at dropping the bracket and rubber coating that as well.

    My plan is really just to do under the back seat and and most of the trunk.

    The in tank pump is more than I want to spend right now. And honestly the EFI we'll probably get ditched someday when I want to put my original engine back in. It's numbers matching.
    I'm not looking for road noise. Just a slight quieting of the pump.
  15. 3175375

    3175375 Well-Known Member

    Just save yourself of a bunch of cash and use earplugs
  16. stangg

    stangg Member

    I used the foil covered Fatmat for my Chevy that I purchased on eBay. I'll be adding it to the floors of my Mustang when I get around to it. Regarding your fuel pump. I thought you used something similar to the MSD 2225. If so, that's the same pump I used on mine. It was terribly loud when I first installed it, but now it is fairly quiet. I just barely hear it when I turn the key. On the drop bracket I added a couple bends to strengthen it and hopefully minimize noise.
  17. RapidRabbit

    RapidRabbit Well-Known Member

    I used the summit pump that is pretty much exactly the same.

    I haven't had time to modify the bracket yet. I'm going to try to add more isolation to it.

    Started the car up yesterday for the first time this year and I can't really hear it when the engine is running anymore. Just when it is priming before starts.

    Sent from my XT1058 using Tapatalk

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