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I am in the middle of soundproofing the rear quarters and I could use some assistance. I have the rear panel off now and there are two large pieces of foam. The rear piece of foam is over the wheel arch, under the window. The second piece of foam is mounted to the panel along side of the B-pillar.
My questions is, should I remove both pieces of foam and just use the sound deadening mounted to the sheetmetal? Or should leave the foam and sandwich the sound deadening in-between?
I have some experience with this. Filling the void is a great idea too, but a quiet Michelin tire would help the most. I've filled voids in autos using 2 part expanding foam. Adds rigity, stops sound, and adds very little weight. You just have to make sure no water can enter the area as it could get trapped.
Also the rear hatch area has lots of hard surfaces, not much to absorb sound. Recovering the rear trim panels in carpet or an Alcantera type material helps reduce some of the boomy'ness of the rear hatch area.
I'm interested in this process also. These cars are loud, even when all the power train vibrations have been eliminated (new motor mounts, TT bearings, harmonic balancer etc).
Based on my ears I think that foam in your pics is pretty useless compared to the foam/mass-loaded vinyl sheets you'll be using. In fact the factory soundproofing is pretty bad except the rear seat wells in '90+ cars, which is a molded version of what you are using. On my car even that is badly cracked and probably useless.
I don't have any direct experience with soundproofing but I have done a lot of reading and hope to start work soon. So your experience will be a big help.
https://www.sounddeadenershowdown.com/ has a lot of information that seems credible. I have no affiliation but a lot of people online in other forums have quoted the site. The guy describes a 3 step process: Damping any vibrating surface, i.e. sticking a layer of something heavy (e.g. Dynamat) to it to raise mass/lower resonance frequency, is the first step. The foam/MLV laminate is the second step, providing a so-called limp barrier (the MLV) and isolating it from the panel (the foam substrate) for any vibrations the damped panel creates. The third step is to add midrange absorbing foam (like the Roxul @Speedtoys mentioned). The foam on the interior wheel well might be analogous to that.
Anyway, good luck and please keep posting on this topic!
Sorry - english not good. My poorly worded meaning was that Roxul might fill that third step of midrange sound absorption. Also I was too squishy on the definition of 'foam': In this case it's expanded melamine in flat panels cut to fill voids. Not spray-in expanding foam or open cell soft material. Not sure if any of that makes a difference.
I stuffed the air space behind the rear 6 inch speakers in the b pillars with 3M Thinsulate so that the ventilation path of the car is still functional.
That area flows air out of the vehicle. If it was blocked with expanding foam your windows will fog up and the air inside will get stuffy.
You gotta look into stuffing Roxul up into the pillar ahead of the rear wheels, I did.
The door latch panel is _right_ there, and its a huge area of resonant road noise.
Also used this behind the front tires, in the washer bottle and cruise control cavities
speedtoys, can you tell us more about Rolux and how and exactly where you installed. does this material absorb
moisture? did you install this behind the forward rear wheel well cover? noticeable difference?
Based on my ears I think that foam in your pics is pretty useless compared to the foam/mass-loaded vinyl sheets you'll be using. In fact the factory soundproofing is pretty bad except the rear seat wells in '90+ cars, which is a molded version of what you are using. On my car even that is badly cracked and probably useless. https://www.sounddeadenershowdown.com/ has a lot of information that seems credible. I have no affiliation but a lot of people online in other forums have quoted the site. The guy describes a 3 step process: Damping any vibrating surface, i.e. sticking a layer of something heavy (e.g. Dynamat) to it to raise mass/lower resonance frequency, is the first step. The foam/MLV laminate is the second step, providing a so-called limp barrier (the MLV) and isolating it from the panel (the foam substrate) for any vibrations the damped panel creates. The third step is to add midrange absorbing foam (like the Roxul @Speedtoys mentioned). The foam on the interior wheel well might be analogous to that.
Thanks for the suggestion on this website, I will likely follow steps 1 and 2 from this site.
I decided to remove the foam since it wasn't searching any useful purpose. After some extensive cleaning with solvent to remove all the foam and glue I had the metal wheel well exposed. I added Cascade Audio VB-2 mat to the metal surface (http://cascadeaudio.com/car_noise_control/vb_2.htm). And then glued the foam/rubber loaded blanket over the top (http://cascadeaudio.com/car_noise_control/vb_4.htm). Additionally I took the time to add VB-2 in the cavity for the speaker as best as I could and then stuffed it with remnants of the loaded mat. I just did the one side so I'll give report on how well it worked.
I didn't get the best pictures of the foam removal or the moldable mat before added the loaded foam mat. Here are a couple bad pics of the mat installed before adding the trim back on. I'll get better pictures when I do the other side.
Also, I decided to make some improvements to my rear speaker mounting since I noticed they make some vibrations at times. I added some epoxy to the grills which are just press fit in.
A local installer, Mobile West Mad up these nice adapter plates. I added some rubber inner tube from a bicycle to make them fit tight against the mounting surfaces to ensure a vibration free fit.
Michael, any update? FYI, I put a toe in the water today - took about 15 minutes and cut a piece of 1/4" neoprene foam and 1/8" MLV for under the hatch carpet. The exhaust and road noise is noticeably lower. Very encouraging!
Michael, any update? FYI, I put a toe in the water today - took about 15 minutes and cut a piece of 1/4" neoprene foam and 1/8" MLV for under the hatch carpet. The exhaust and road noise is noticeably lower. Very encouraging!
The results are fantastic! The sound dampening has really reduce the overall road noise and I am much happier now. I would compare the road noise of this car to a modern car now and I think the biggest improvement was to the rear quarters. The sound dampening on the doors helped some but didn’t have as big of an impact as the rear quarters. I have not insulated the floor of the trunk or the parts behind the tool panel But I don’t think I need to do that either
07-06-2018, 01:55 PM
Sound proofing rear quarters
