Sound deadening project

[Felix2021]

That foam that is there, usually doesn't do a very good job for some reason. It's not strictly acoustical foam.

So using a butyl mat mat and acoustic foam on a wheel arch usually brings quite an improvement. Some people are also using mats outside, on the plastic wheel arch cover.

[SkOmk4]

In an unfortunate event (that was also the end of my Megane GT - some smart guy making a U-turn in front of me on an expressway) I found out what Renault did to keep the noise from the wheel arch away from the cabin. Inside the empty volume that is delimited by the front fender on the outside, the engine compartment on the inside and the wheel arch on the bottom, those guys added a plastic bag that was filled with foam bubbles/flakes. I can tell you that it did a pretty good job - there was no noise coming from the wheel/road contact/friction. If there was any, it was covered by the noise coming from the A-pillar and/or side-view mirrors.

And yes, what U see in the picture is a broken plastic front fender - Renault was using that since Megane 2; it's designed to shatter into pieces on impact and thus dissipate as much energy as possible...

[Jorgeminator]

B-pillars done. There was some factory foam in the sill already and some sort of padding inside the lower trim panel.

I put butyl mats over the large holes in the frame to stop sound from escaping through them. Also added some acoustic foam in the cavity at the bottom and insulated the trim with closed cell foam. First impression is less wind noise from the side at speeds above 100 km/h.

 

 

 

 

 

 

 

Edited 31 August, 2022 by Jorgeminator

[Jorgeminator]

18 hours ago, Felix2021 said:

That foam that is there, usually doesn't do a very good job for some reason. It's not strictly acoustical foam.

So using a butyl mat mat and acoustic foam on a wheel arch usually brings quite an improvement. Some people are also using mats outside, on the plastic wheel arch cover.

Closed cell foam on the arch liner plus mats on the exterior wheel arch should probably work. Tyres have to come off, so I might do it while changing to winter tyres later this year.

[Jorgeminator]

Front wheel arch liner, driver's side:

 

 

A piece of butyl on the inside of the hollow sounding fender:

 

[TheUltraRunner]

Did you said you'll do that later when changing tires? 😁

Good job! 

[SiWaiting]

Really interesting to follow your progress @Jorgeminator! Great pics and descriptions!

[Jorgeminator]

3 hours ago, SiWaiting said:

Really interesting to follow your progress @Jorgeminator! Great pics and descriptions!

Thanks, much appreciated!

 

I was running out of ideas what to do next, except the passenger side wheel arch, so I tapped my way around the cabin. Noticed that the plastic trim around the tunnel in front sounded thin. The lower trim piece comes off super easily, only one torx screw close to the throttle pedal and the whole piece pulls straight down. I deadened the piece I pulled off and added some insulation inside the upper trim where I could reach by hand.

 

 

 

[Felix2021]

Ok, can you tell us what difference wheel arches made? Super interested in that

[Jorgeminator]

41 minutes ago, Felix2021 said:

Ok, can you tell us what difference wheel arches made? Super interested in that

I have only done the driver's side so far, but to be fair, I didn't notice much of a difference. Will have to do the passenger side still, since I've heard that's where the majority of the noise comes from. I will update you when it's done.

Although, I must say I didn't have much tyre noise to begin with, running on Goodyear EfficientGrip Performance 205x55 R17 tires. Really quiet ones in my opinion.

 

The trim parts could be placebo, but it felt like the droning on rough surfaces decreased after I did them 🤔

 

EDIT: A good indicator of something done right, I can now clearly hear the turbo spooling, and the turbo on the 1.5 TSI is not exactly loud. I never heard that before doing the soundproofing.

Edited 2 September, 2022 by Jorgeminator

[Vlady]

Nice thread to follow, well done for shearing and effort. Thanks

Keep it going.

[Felix2021]

13 hours ago, Jorgeminator said:

Although, I must say I didn't have much tyre noise to begin with, running on Goodyear EfficientGrip Performance 205x55 R17 tires. Really quiet ones in my opinion.

I guess that's mostly due to the size. I have 225/45R18 and tire noise quite loud on some surfaces. That's why i'm particularly interested in this.

Although living in Finland, you should know what i'm talking about  I don't know if its because of tarmac used, or because in Scandinavia you can use tires with spikes, but i noticed tire noise to be much, much louder in Scandinavia, than for example in Poland. Done roughly 2,5k km through Finland, Sweden and Denmark this summer.

Waiting for your impressions when passenger side is done

[Jorgeminator]

41 minutes ago, Felix2021 said:

Although living in Finland, you should know what i'm talking about  I don't know if its because of tarmac used, or because in Scandinavia you can use tires with spikes, but i noticed tire noise to be much, much louder in Scandinavia, than for example in Poland. Done roughly 2,5k km through Finland, Sweden and Denmark this summer.

Waiting for your impressions when passenger side is done

I know very well 😄 It's a combination of the tarmac used and people using studded tires. Studs will wear the surface so they put a coarser tarmac compound to reduce the wear.

[Felix2021]

That explains all

Although it's actually interesting, that smaller roads in Tampere area were more quiet, than in Helsinki area. I would expect more people with studded tires in the north

[liveseytowers]

Loving seeing this come together   Did you record a before video and any plans to doing an after video?  For me the tyre noise is my biggest gripe, the car is so noisy when i get on the motorway.  I can't wait to burn through my current OEM set and replace them with something else.  

[JirikH]

Did you check, how many KG had material what is already installed? How much weight the car gain? But have to say I am impressed by the scope of work you have done. Really beautiful.

[Jorgeminator]

Thanks to everyone for your encouragement and support 🙂

The front exterior arches are now finished. I didn't bother insulating the front facing part of the liner on the passenger side since it faces the engine compartment, the auxiliary heater being closest to the liner. Pictures below.

 

 

 

 

 

On 05/09/2022 at 13:36, liveseytowers said:

Loving seeing this come together   Did you record a before video and any plans to doing an after video?  For me the tyre noise is my biggest gripe, the car is so noisy when i get on the motorway.  I can't wait to burn through my current OEM set and replace them with something else.  

Unfortunately, I forgot to record a video prior to starting the project. Would indeed have been nice to compare the results. I listened to some of my dashcam footage after insulating the car, but the sound does not really represent what you hear as a driver/passenger. I might record a video with my phone if I find a way of fastening it in the cabin.

 

On 05/09/2022 at 13:47, JirikH said:

Did you check, how many KG had material what is already installed? How much weight the car gain? But have to say I am impressed by the scope of work you have done. Really beautiful.

 

Around 16 kg of material has been added in total.

[Jorgeminator]

Up next: Rear wheel arches from the inside and quite possibly the front floor area (+ arches from inside). I've been studying the repair manuals to figure out how the side trim in the boot comes off. Shouldn't be too difficult considering I don't have the rear side airbags. The front floor trim should be easy now that I know how the lower trim part on the center console comes off.

These are probably the last areas I'll insulate, leaving only the roof and rear floor (the foot area for the rear occupants) uncovered. I'd be interested to hear opinions on the roof. Has anyone done it on other cars? How much did it improve noise levels?

Edited 16 September, 2022 by Jorgeminator

[Jorgeminator]

Progress. I will remove the factory insulation while applying mats and foam. The factory pieces come off in one piece if careful, so they can be reapplied on top of my own material if they still fit.

 

 

[Jorgeminator]

Rear wheel arch on the left is done. While in there, I discovered that the side panel acts like a huge subwoofer. Anyone with the limousine, put your head inside the boot and tap the outside panel in the area pictured below. I can't believe how noisy that panel is. Second picture is the sound spectrum it makes. It produces a 55-60 Hz tone. The second harmonic at 110-120 Hz can also clearly be seen.

 

 

[Jorgeminator]

More pics 😄

 

Rear wheel arch from inside trunk.

 

Front facing portion of rear wheel arch.

 

Passenger side carpet lifted as far as it will go without removing seat or center console parts.

 

Several layers of butyl on the floor panel and some (unnecessary?) on the foam just because I couldn't reach that far below it and I was too lazy to start disconnecting wiring and stuff to remove it. Small patches on the air tunnel going to the rear vents to reduce rumble.

[Vlady]

That will be one quite Skoda! Well done and thanks for the updates!

How expensive is the insulation material you are getting?

[Jorgeminator]

1 hour ago, Vlady said:

That will be one quite Skoda! Well done and thanks for the updates!

How expensive is the insulation material you are getting?

 

Thanks! The materials used so far cost around 300€. The butyl sheets are ~25€/m². Closed cell foam is 25-30€/m² depending on the thickness, 6mm or 10mm.

[Priidik]

Very good project, thank you for sharing.

 

Give us top 3 places, what made the most difference?

What's the total weight you have added to the car?

[Jorgeminator]

10 hours ago, Priidik said:

Very good project, thank you for sharing.

 

Give us top 3 places, what made the most difference?

What's the total weight you have added to the car?

 

I'll give it a try 😄

 

1. Boot floor and under rear seat; less rumble overall

2. Doors; loose wiring rattles gone, plus firmer sound when closing

3. Wheel arches; less tyre/debris noise

 

The total weight added is now at roughly 20kg.