DIY Soundproofing

AshCupra300

Active Member
Sep 16, 2006
381
65
Newport, South Wales
Had a few motorway trips this week in my Cupra, wow its one noisy biatch when it comes to outside and road noise....
Even in a car park in Cardiff today that has the main road to the M4 behind it, it sounded like I had left the boot open and could hear the noise of traffic quite a lot.
I need a how to guide to sound deaden the rear noise of the wheels/road noise, I take it rear bench, arches and boot?
Tyres are Pirelli PZero 19s

Oh and its a Facelift..
 

Bouloama

Active Member
Aug 10, 2018
32
4
Any one who knows how to remove the inner lining carpet from the wheel arches in a Leon ST? Want to apply deadening material to the wheel arches too ..
 

worleyg

Active Member
Nov 13, 2012
41
9
Any one who knows how to remove the inner lining carpet from the wheel arches in a Leon ST? Want to apply deadening material to the wheel arches too ..
Quite simple. You need to remove the trim on the boot door area, three screws and a sharp tug upwards. After this comes out there are two torx screws (one is behind the rear seat release lever) on the side lining, and also the luggage ring has another third larger torx nut behind it. Youll need to give the white trim a good tug to release it and then you should be able to lever it out to see most of the wheelarch. To get to he front of the arch requires taking out the rear seat and remove the side trim by the rear seat door.
 

Ashead

Active Member
Dec 29, 2018
11
2
Hi
Just adding my experience to the thread.
I've found my cupra too noisy, presumably due to the bigger tyres (than previous 17").
I stripped the boot and rear seat and clad with 2mm foil backed rubber stuff (like silent coat). I did notice this shift the noise to the front slightly so must have made some difference. I then tried to do a bit around the front floor and doors. I struggled to add much to the floor so didn't feel like this made much difference, so...
I then added some 40mm foam to the front doors. This made a noticeable difference to the stereo and now the road noise sounds more like it's coming from the rear again.
Therefore the work must make a difference but I'm still struggling with the noise so don't think it's made much of an absolute difference. Admittedly this is a DIY job with cheaper products but thought worth sharing.
My next job is to add some foam to the boot and rear doors just to give a more satisfying thud on closing. And grease the squeaky back door.

I had the front wheel arch panel liner off and note that the standard insulation is just white fluff, so suspect upgrading this to foam could help a little. Not looked at the rears yet to see if anything could be done.

My other thought is whether the 'flicks' to the wheel arches in the cupra create more wind noise somehow?
 

Deleted member 103408

Guest
Hi
Just adding my experience to the thread.
I've found my cupra too noisy, presumably due to the bigger tyres (than previous 17").
I stripped the boot and rear seat and clad with 2mm foil backed rubber stuff (like silent coat). I did notice this shift the noise to the front slightly so must have made some difference. I then tried to do a bit around the front floor and doors. I struggled to add much to the floor so didn't feel like this made much difference, so...
I then added some 40mm foam to the front doors. This made a noticeable difference to the stereo and now the road noise sounds more like it's coming from the rear again.
Therefore the work must make a difference but I'm still struggling with the noise so don't think it's made much of an absolute difference. Admittedly this is a DIY job with cheaper products but thought worth sharing.
My next job is to add some foam to the boot and rear doors just to give a more satisfying thud on closing. And grease the squeaky back door.

I had the front wheel arch panel liner off and note that the standard insulation is just white fluff, so suspect upgrading this to foam could help a little. Not looked at the rears yet to see if anything could be done.

My other thought is whether the 'flicks' to the wheel arches in the cupra create more wind noise somehow?


Have you checked to see if the previous owner had removed any of the baffles on the exhaust and did they turn off the sound thing when in Cupra Mode.
 

Ashead

Active Member
Dec 29, 2018
11
2
I've disconnected the sound aktuator. Think the exhaust is stock. It's a drone related to road speed and general road noise that bothers me. Wondering if the diffuser and under body on the Cupra generate some additional noise.
 

the stripler

Fighter pilot on Rails
Apr 8, 2014
87
0
Lanark, Scotland
Has anyone done this mod in Scotland? Or know of anywhere up here that does it?.

Id like to get it done if i can be advised by anyone that it does actually work.

Purely want to lesson the road noise
 

moriarty

Active Member
Apr 6, 2015
96
14
Edinburgh
I hadn't spotted this to thread before, Not on a modern car but I fitted the NK soundproofing kit to my Morris Traveller- yes a 1971 family estate (,originally my Dad"s from new) to go with the 2019 Leon ST.
The NK kit has had an amazing effect on what was a very noisy car, quieter and less harsh but also feels more solid.
Since they didn't do a specific kit for my car I got a pile of off cuts and large sheet of self adhesive sound proofing for the load area. Its the only bit of the Morris I haven't done yet and to be honest I intend putting it under the boot floor of the Leon.
A word of warning though, the sound proofing weighs a lot, it got dropped off at my work and I had to bring the car up to the door to get it home, I expect the Leon kit will be bigger and heavier.
 

the stripler

Fighter pilot on Rails
Apr 8, 2014
87
0
Lanark, Scotland
I hadn't spotted this to thread before, Not on a modern car but I fitted the NK soundproofing kit to my Morris Traveller- yes a 1971 family estate (,originally my Dad"s from new) to go with the 2019 Leon ST.
The NK kit has had an amazing effect on what was a very noisy car, quieter and less harsh but also feels more solid.
Since they didn't do a specific kit for my car I got a pile of off cuts and large sheet of self adhesive sound proofing for the load area. Its the only bit of the Morris I haven't done yet and to be honest I intend putting it under the boot floor of the Leon.
A word of warning though, the sound proofing weighs a lot, it got dropped off at my work and I had to bring the car up to the door to get it home, I expect the Leon kit will be bigger and heavier.
So, have you fitted anything to the leon yet?
Id be really interested to hear how you get on with it.
 

agentman

Active Member
Mar 13, 2020
26
9
I finally got around to applying some soundproofing to my Leon ST. For material, I used STP Aero. I'm planning on buying additional foam-like sheets. I did rear-arches (from the inside), rear bench, a bit of boot floor area and front left wheel arch (outside plastic lining).

The reason I did only 1 front wheel arch, is because my jack broke in the middle of raising the car. It just didn't go any higher but was enough to take the wheel off, which I actually shouldn't have done..Afterward, I realized there's not enough clearance to put the wheel back on as there's about 1cm of height missing....
Lowered the car onto some hard logs and used a spare jack that's not been used in 30 years to get it back up again..thankfully all went well.

The whole procedure took approximately 5 hours. Boot trim disassembly was the most time consuming, even though I had the workshop manual on hand.
I would say there's a noticeable improvement, which can be definitely felt at city speeds. Ride over rough asphalt is still quite noisy.

Next step is to buy more insulating material and do the remaining wheel arches from the outside, as well as the doors.
 
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