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2017 Outback
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Discussion Starter · #1 · (Edited)
I have applied Noico sound dampener inside all 4 doors and under the cargo area but I'm still in search of a quieter car. I found a few posts on other forums about removing the plastic wheel liners and applying closed cell foam to the back side of them...and adding Noico to the metal fenders, too. But there aren't many threads about this so I wonder if it's worthwhile?

On most roads my car is quiet enough but there are areas on I-40 in Western North Carolina that cause a lot of tire noise and I'd like to fix that. I haven't applied much closed cell foam because I don't want to cover the access holes in the doors. I'm still having trouble with the driver's side power window not going up like it should. And, yes, the dealer and I have reset the window programming multiple times. I may have to get to the motor or the harness before it's fixed for good.

BTW, I'm still running the factory installed Yokohama Geolanders with 20k miles on them. They have plenty of tread and are wearing evenly.
 

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Sahuarita, AZ 2018 Forester Limited
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2,816 Posts
If you don't have a cargo cover, installing one will muffle some of the noise from the rear tires.
 

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I have applied Noico sound dampener inside all 4 doors and under the cargo area but I'm still in search of a quieter car. I found a few posts on other forums about removing the plastic wheel liners and applying closed cell foam to the back side of them...and adding Noico to the metal fenders, too. But there aren't many threads about this so I wonder if it's worthwhile?

On most roads my car is quiet enough but there are areas on I-40 in Western North Carolina that cause a lot of tire noise and I'd like to fix that. I haven't applied much closed cell foam because I don't want to cover the access holes in the doors. I'm still having trouble with the driver's side power window not going up like it should. And, yes, the dealer and I have reset the window programming multiple times. I may have to get to the motor or the harness before it's fixed for good.

BTW, I'm still running the factory installed Yokohama Geos with 20k miles on them. They have plenty of tread and are wearing evenly.
Measurements have shown that covering 25% of sheet metal stops 95% of the resonance noise from the sheet metal. After that a layer of closed cell foam with mass loaded vinyl on top is the way to go.

Tire noise is the hardest thing to mitigate and most recommend switching to quieter tires as most effective. Running A/Ts isn't helping. I believe the Geo G015 is quieter than the Geo S. Also, tires get louder as they wear. Nioco doesn't do well on high heat areas.

Read up here. The guy that ran SDS retired and closed down a few months ago. It appears ReSonix may have bought the rights to SDS' products.
https://web.archive.org/web/20190129013346/https://www.sounddeadenershowdown.com/
https://resonixsoundsolutions.com/reference-information/
 

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2017 Forester XT CVT (High Torque)
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254 Posts
I have applied Noico sound dampener inside all 4 doors and under the cargo area but I'm still in search of a quieter car. I found a few posts on other forums about removing the plastic wheel liners and applying closed cell foam to the back side of them...and adding Noico to the metal fenders, too. But there aren't many threads about this so I wonder if it's worthwhile?
I found a surprising amount of noise reduction by covering the inside of the rear lift gate with Vibro Black 80 mil (similar to Dynamat Xtreme) as well as Vibro 6mm closed-cell foam.

I used the Dynamat versions on the doors first, but was surprised at the improvement when I wrapped the rear lift gate and rear inside fenders (under the cargo side trim) prior to installing a rear subwoofer. It helped with rear-wheel noise as well as exhaust drone (which made it easier to hear the engine/turbo, nice!). Dynamat is slightly easier to cut and use, but Vibro performance is equal or slightly better and it’s half the cost.

I wouldn’t expect much improvement from doing the front wheel wells. But then again, I didn’t expect the rear lift gate would help that much. Personally I’d try a hood wrap first with something that can take high temperatures. Especially on the non-turbo models where you can wrap the entire hood and don’t have a turbo scoop in the way.



BTW, I'm still running the factory installed Yokohama Geos with 20k miles on them. They have plenty of tread and are wearing evenly.

Those Yoko Geos are notorious for being noisy. There are plenty of quieter choices, especially if you get an all-season M/S rated touring tire, rather than an AT or LT tire. Tire Rack has reviews which mention noise.
 

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2017 Forester XT CVT (High Torque)
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254 Posts
I found a surprising amount of noise reduction by covering the inside of the rear lift gate with Vibro Black 80 mil (similar to Dynamat Xtreme) as well as Vibro 6mm closed-cell foam.
I forgot to mention one other thing that I did that helped a lot. I already had the factory carpet floor mats, with the Subaru all-weather mats on top. I added full floor mats from Findway.ca, and stacked them carpet first, Findway mats second, and Subaru rubber mats on top. I used an extra set of floor mat retainers and zip ties to keep the rubber mats in place up front. I also have the Subaru rubberized plastic cargo liner in the back.

I like the Findway mats a lot. They are custom-fitted, weather proof, easy to clean, but look original. The top has a closed-loop synthetic carpet that is spill-proof, and the backing is rubberized. They hose off and dry fast. They don’t get slippy when wet or muddy. I think they are heads and shoulders better and more attractive than the WeatherTech ones.

They also isolate road noise very well, especially with all three layers.
 

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2017 Forester XT
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187 Posts
I have applied Noico sound dampener inside all 4 doors and under the cargo area but I'm still in search of a quieter car. I found a few posts on other forums about removing the plastic wheel liners and applying closed cell foam to the back side of them...and adding Noico to the metal fenders, too. But there aren't many threads about this so I wonder if it's worthwhile?

On most roads my car is quiet enough but there are areas on I-40 in Western North Carolina that cause a lot of tire noise and I'd like to fix that. I haven't applied much closed cell foam because I don't want to cover the access holes in the doors. I'm still having trouble with the driver's side power window not going up like it should. And, yes, the dealer and I have reset the window programming multiple times. I may have to get to the motor or the harness before it's fixed for good.

BTW, I'm still running the factory installed Yokohama Geolanders with 20k miles on them. They have plenty of tread and are wearing evenly.
Coincidentally, I did it recently for my 2016 FXT front wheel fender liners with Noico butyl sheets. Honestly, I didn’t find a big improvement despite covering each fender liner almost entirely... I originally planned to do the rears but decided not to.

So unless you have spare soundproofing sheets lying around and in the mood for some DIY, i would suggest giving it a miss. Like what other members have shared, best reduction in tire noise is by picking a set of quiet tires.
 

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2017 Forester 2.5i MT
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324 Posts
DOOO, how thick was the material you added? Did you replace all of Subaru's rigid foam?
 

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2015 Forester XT Touring
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693 Posts
Remember that 2017+ Foresters saw upgrades in sound deadening that earlier models don't have. The windshield alone probably helps for a few db's at highway speed. Results may vary from adding sound deadening to earlier models.
 

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2017 Outback
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122 Posts
Discussion Starter · #11 ·
Watch the ads for Aldi and Walmart and buy a yoga mat for under $10. Then cut it to lay under the spare tire and you'll notice a big change in noise. Those mats are really good as sound insulation.

I decided to remove both rear fender liners. They are held on with plastic clips that are easy to remove. Just lift the center circle and the whole clip pulls out. The driver's side rear liner has some cotton batting attached to the top of the arch but the other side has nothing. Then I added Peel and Seal to the metal and closed cell foam to the back of the plastic fender liners. There's probably no science to explain why this helped but it did.

I've had very good luck with Peel and Seal on four cars ($16 /roll at Lowes and has no odor at all) but I've read that some people ended up with a sticky mess. All I can say is to apply it during hot weather to insure good contact and use a roller. It's not as sticky or as thick as Noico but it's cheap and does a good job. I have never applied it to a car roof and probably would not unless I were adding extra glue.

I have a trip planned and will decide after that if I'm going to do the front liners. Seems like most of my noise was from the rear of the car. When I need tires I'll buy General Altimax RT43 in size 215 65 17 and that will probably my last step in my quest for a quiet car.
 
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