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DIY – Soundproofing / dampening the wheel arch


The wheel arch area is well known to transmit vibrations or sounds from a noisy tyre and bad road conditions directly into the cabin resulting in the extremely annoying ‘wooing’ droning noise that everyone who drives a Proton Wira will be familiar with. The irony of this is that Proton themselves have tried to remedy this issue by coating the wheel arch with a layer of rubberized coating. Trust me when I tell you it’s not enough.



Anything above 85dB (decibels) will damage the hair lining in your inner ear (if exposed long term) which effectively damages your hearing. My car (according to a Android app) was recording a shocking 91dB whilst going at 80km/h along the Federal highway. Yokohama Cdrive2 tyres – 230kpa of pressure, stock rubberized coating sound proofing, cabin carpets and a whole lot of things in the way and it still recorded a shockingly high 91dB (averaged out figure). That cannot be good.


Time to top up or reinforce the rubberized coating for the car. After some searching in some forums and the ZTH marketplace, I came across a fellow ZTH-er XTORM and his soundproofing solution thread. A quick chat on the phone and soon he had me buying several cans of Dupont Rubberized Coating specially made for undercoating the car and all. Perfect.


First things first, the wheel and the inner fender leaf came out after several bolts were removed. The inner fender arch was then scrubbed down to remove dirt, tar, embedded stones and mud. For the coating to properly stick, it’s better to have it clean. I want the rubber to be on the car body, not contaminated with stones and dirt.


Next up, wrap all the sensitive parts of your suspension and what not with newspaper. This is a spray can application. You spray everywhere, it’ll go everywhere, including areas that aren’t supposed to be sprayed. I just spent a small fortune on adjustable suspension, I wasn’t going to ruin it all because of a few decibels! Yes.. my suspension is more important than my hearing. Bah humbug.


Essentially since it’s a spray can, just spray thin layers anywhere there’s metal. I even sprayed on the arch leaf but that was just for fun. No real effect I should think? After 2 cans of spray and about 30 minutes drying intervals between each coating, the layers started to look promising.


It’s smooth and rubbery to the touch and if you try to knock it with your knuckles, you’ll get a very satisfying thud rather than the hollow tinny sound you get with most locally manufactured cars.

I basically used up 4 cans per arch before I was completely satisfied with my work. However since I only bought 8 cans, that meant I only coated the front two arches. Time for a test drive!


Woah.. 4dB reduction! It was audibly muted, though still apparent, the lower frequencies were muted and it was less drone-y. Quieter. Not bad! Works! The only thing now is to buy another 8 more cans to cover up the rear. This time though I’m buying a mask. The fumes made me queasy and word of warning to those who want to try this – make sure you’re doing it in a very well ventilated area. The smell is going to invade your house, your nose and if enough, your brain! What a high!

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    Ivan
  • May 31, 2013
hi bro nice review! 4 cans per arch, WOW :D
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    mao
  • May 31, 2013
was having an idea to do this as well.. since my mudguard is always thorn apart.. i'm thinking of ditching the mudguard & just apply a thick layer of this under the wheel arch.. where to get the spray?
Buy it off Xtorm lor.
Link is in my post
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    armandd
  • Jun 2, 2013
How much weight it added to your car (for 2 wheel arches)?
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    risham rahim
  • Jun 30, 2014
Hi boss..inner fender leaf also been sprayed over?
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    j
  • Jul 1, 2014
no like button?
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    john creed
  • Sep 6, 2016
I did my arches with silent coat 2mm sound dampening inside the arches and outside, then added a layer of dodo barrier mat over the top of the silent coat on the inside and some closed cell foam over the top of the silent coat on the outside. Then I applied another load of closed cell foam to the arch liner and then fixed it back in place. Then I got a butt load of expanding foam and peeled back the arch liners and sprayed a load of it in the gap between the arch liner and the car body within the wheel well avoiding it obviously intruding onto any mechanical components etc.


The noise reduction was dramatic, when going over bumps, and the tyre roar was massively reduced. I felt as if I was in a bentley when I was doing 70 mph even though I was in a Peugeot 106!



In my experience the best way to reduce tyre roar is to use lots of foam rather using weighty bitumen pads and also get a good set of tyres which are renowned for being quiet like the Goodyear Vector 4 season tyres or pretty much most continental's.
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what does the foam do with the metal when applying the foam?
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