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Acoustic insulating Project - 3 leaks found so far

Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
Good morning folks, this has likely been done before but as i am new, i can't find it. If there's an existing thread out there, perhaps someone could point me towards it...

I recently upgraded my speakers across the front of the car. While i am pleased with the improved sound, above 40-50mph(80kph) i still feel like i'm having to crank up my music to hear it correctly. I feel i now need it uncomfortably loud when i am travelling on Motorways or i'm just missing frequencies. So i set off trying to learn about noise in the cabin.

Using a free sound meter app(Not ideal i know), I have the following,

53db @ Idle
67db @ 30mph
70db @ 40mph
73db @ 50mph
77db @ 60mph
80db @ 70mph

These were all taken on a fairly rough piece of Dual Carriageway but it's fairly typical of what i'm driving on i think. The car feels to me unnecessarily loud, but maybe i'm too deeply involved that i want to convince myself that that's my issue. Either way if i could get these numbers down a bit i'd be delighted!

So far I have, stripped the car from the back seats rearward and found the dreaded rear pressure relief vents leaking (L/H & R/H) and the VW boot handle drain pipe leak. 2 days to fix them!! I have put down Dynamat Xtreme wherever i have found thin sheet metal that flexes easily. i'd say i've covered 60% of available metal back there. I will now move forward where i would expect to make the most gains however, perhaps Dynamat xtreme will only deaden vibration induced noise and what i really need is to put in Dynaliner(or similar) on top of whatever i feel is weak in relation to allowing sound to pass through.

Assuming i'm on the right track, for anyone that's done this,

Where did you find the worst areas in the Golf Vii?
Is there any sound insulation on the floor pans other than the carpets?
What are the firewalls like? Do you improve them from inside or outside?
Is a hoodliner worth it?

I'd appreciate any info you folks have on this. I'm in my late 30's and this is only my 2nd car, I have had this for 4 years and can't see me letting go of it for another 4 years at least, so it is worth putting time into it. I'm also an Engineer by trade so i have plenty of ability, my Engineering background is not Automotive so i would enjoy learning from anyone elses experience in trying to quieten their Golf.

Cheers!

Tel
 

Litespeedgti

Ready to race!
Location
Little Rock,Arkansas
Car(s)
2019 GTI S DSG
Hi Tel,
Of the few times I've been to and driven in the UK, traveling the way from Bexhill-on-Sea was the best due to the great roads going to West Sussex. You are on rough roads for sure. As an American, I miss my trips to the UK!

You have done all you can it appears with sound deadening. One thing I have noticed is the interior sounds are always elevated when I have removed the interior privacy panel and lowered the rear seat back. Run your readings and see.

Try placing something "puffy" like wadded up wool under the front seats by sliding it in from the rear. This will add additional sound insulation from the floor boards.

Much road noise is transmitted from the tires. Higher mileage tires often become noisy. its possible that rotation might help. You might research the noise level of your next set. The manufacturer won't provide this information but user reviews are helpful.

Good luck.
LitespeedGTI
 

riceburner

Autocross Champion
Location
West Chicagoland
Car(s)
MK6 and MK7
^yes, TIRES can make a night and day difference!!

OP you are 100% on the right track. I too used a dynamat comparable material over large portions of the rear seats back (including under the rear seats) and then put a MDF Foam padding over 100% of touchable surfaces prior to reinstalling all of the rear panels and carpeting. It didn't blow my mind by any means, but certainly helped absorb some road noise.

I have heard more than a few times now - and this is a double whammy - that undercoating the car helps with noise, and i think i believe it! Added benefits are lwoer center of gravity (marginal) and of course, corrosion prevention!
 

Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
Hi Tel,
Of the few times I've been to and driven in the UK, traveling the way from Bexhill-on-Sea was the best due to the great roads going to West Sussex. You are on rough roads for sure. As an American, I miss my trips to the UK!

You have done all you can it appears with sound deadening. One thing I have noticed is the interior sounds are always elevated when I have removed the interior privacy panel and lowered the rear seat back. Run your readings and see.

Try placing something "puffy" like wadded up wool under the front seats by sliding it in from the rear. This will add additional sound insulation from the floor boards.

Much road noise is transmitted from the tires. Higher mileage tires often become noisy. its possible that rotation might help. You might research the noise level of your next set. The manufacturer won't provide this information but user reviews are helpful.

Good luck.
LitespeedGTI
Hi Litespeed, thanks for the reply :)

What a coincidence, i'm living in West Sussex! Thanks for the additional tips. I may not have been clear, so far i have only applied Dynamat Xtreme to the trunk area, trunk door, rear sear bench and rear wheel arches. The whole front of the car is still ahead of me! I was gonna just dynamat Xtreme the doors and floors from here on but it seems putting Noico 4mm or 8mm on top of that will be a good idea once i start to work those areas! I'll look into the tires too.

Thanks for the tips and replying :)
 

Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
^yes, TIRES can make a night and day difference!!

OP you are 100% on the right track. I too used a dynamat comparable material over large portions of the rear seats back (including under the rear seats) and then put a MDF Foam padding over 100% of touchable surfaces prior to reinstalling all of the rear panels and carpeting. It didn't blow my mind by any means, but certainly helped absorb some road noise.

I have heard more than a few times now - and this is a double whammy - that undercoating the car helps with noise, and i think i believe it! Added benefits are lwoer center of gravity (marginal) and of course, corrosion prevention!

Thanks Riceburner! When i started this last week i began with the trunk as when i had stripped it out i saw load of metal work that could do with a dampening material, but the more i learn, it seems this area will be a gain but not nearly as much as the doors and floors! Glad i've spent that time doing the rear first now as i've learned alot and will def put down noico in the front and hopefully get some big wins!

It's amazing once you are aware of the general noise then it's all you can here! I could really do with this car being quieter as i start a long commute and night work in the new year. Thanks again for your advice/experience :)
 

riceburner

Autocross Champion
Location
West Chicagoland
Car(s)
MK6 and MK7
oh yes, it is easy to fester over all of the little details and make them out to be much worse than they actually are. that said, these definitely aren't quiet riding corollas, and hearing the jarring rattles and road noise over every bit of road is just not needed!

I really think i should go get undercoat sprayed now! For ~3-500 USD (what's that, 40,000 quid? ;) ) i think it could make quite a difference for no work on your behalf.
 

Yungaxel3

Passed Driver's Ed
Location
SF Bay Area
Car(s)
'19 GTI DSG Autobahn
What a coincidence, my Noico 80mil sound deadener just came in. I was planning on just lining the trunk. Was there a noticeable difference in noise from the rear by doing just that? I might layer with the Noico 315 mil too
 

golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
MK7 Golf GT Estate
As you have the "R-Line" you should have the multi-link rear suspension...you can fit the MK8 lower rear arm aero covers..& the rear subframe harmonic damper..both items will reduce inherent resonance from the rear suspension, not masses, but a noticeable difference...You could also retrofit the other undertrays, like the front exhaust tunnel, & the rear exhaust tunnel trays..& the short rear axle undertray from the MK8...also either fit the skid tray or the full aero cover for the engine bay underside...again all reducing the wind turbulence & thus noise..
 

Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
oh yes, it is easy to fester over all of the little details and make them out to be much worse than they actually are. that said, these definitely aren't quiet riding corollas, and hearing the jarring rattles and road noise over every bit of road is just not needed!

I really think i should go get undercoat sprayed now! For ~3-500 USD (what's that, 40,000 quid? ;) ) i think it could make quite a difference for no work on your behalf.
After Brexit, it will be! :rolleyes:

I didnt even know this undercoat existed, i could get lost in a rabbit hole of improvements here. Need to choose carefully :)
 

Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
What a coincidence, my Noico 80mil sound deadener just came in. I was planning on just lining the trunk. Was there a noticeable difference in noise from the rear by doing just that? I might layer with the Noico 315 mil too

Sorry to say, none at all :) But the good news is, i seem to have started with an area that is low on the priority list in terms of gains. From all these conversations and a chat with the guys at Dynamat yesterday, it seems you should go, Doors then floors then bulkhead then trunk then roof.

Also to be fair, all i have done is laid sound deadening back there, not acoustic insulation. All it will really do is prevent vibration induced noise in sheet metal, not protect the cabin from the noise source. Good to have it done still. I'm thinking when the bigger gains are done then this work will compliment them if that makes sense. :)
 

Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
As you have the "R-Line" you should have the multi-link rear suspension...you can fit the MK8 lower rear arm aero covers..& the rear subframe harmonic damper..both items will reduce inherent resonance from the rear suspension, not masses, but a noticeable difference...You could also retrofit the other undertrays, like the front exhaust tunnel, & the rear exhaust tunnel trays..& the short rear axle undertray from the MK8...also either fit the skid tray or the full aero cover for the engine bay underside...again all reducing the wind turbulence & thus noise..
Good Morning Dave, thanks for this reply, it woulda taken me a long time to gather all this information. On first read, i would struggle to understand alot of these terms and what you're getting at, but researching the last few hours its making sense.

MK8 Lower arm aero covers: Is this because my model doesn't have these? Are they a piece of aerodynamic trim that stop my arms from cutting harshly through the airflow(Possibly causing noise and/or buffeting around the suspension)?

Harmonic Dampener: I like the look of this, my local dealer says they can have it by Saturday and i can fit it easily enough, looks like a winner.

Sachs Shock Absorber: Not sure if i have these(Sachs), but i went out just now and banged on both rears, RH sounded ok i think, LH sounded a bit buzzy or rattly. I'm also not sure i have the noise that people claim the Sachs are producing. Maybe it's just lost with all the other 'noise' i have and i don't have the Ear to pick these things out yet. I'm just starting out on my noise reduction journey. :)

The other undertrays?: You say other as i already have some yes? I had a look today and i have a fairly substantial tray under the engine. Then i have one down the LH & RH sides. Other than that, the core looks fairly unprotected.

Thanks again for your replies, love your appetite for this stuff! :)
 

golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
MK7 Golf GT Estate
Good Morning Dave, thanks for this reply, it woulda taken me a long time to gather all this information. On first read, i would struggle to understand alot of these terms and what you're getting at, but researching the last few hours its making sense.

MK8 Lower arm aero covers: Is this because my model doesn't have these? Are they a piece of aerodynamic trim that stop my arms from cutting harshly through the airflow(Possibly causing noise and/or buffeting around the suspension)?

Harmonic Dampener: I like the look of this, my local dealer says they can have it by Saturday and i can fit it easily enough, looks like a winner.

Sachs Shock Absorber: Not sure if i have these(Sachs), but i went out just now and banged on both rears, RH sounded ok i think, LH sounded a bit buzzy or rattly. I'm also not sure i have the noise that people claim the Sachs are producing. Maybe it's just lost with all the other 'noise' i have and i don't have the Ear to pick these things out yet. I'm just starting out on my noise reduction journey. :)

The other undertrays?: You say other as i already have some yes? I had a look today and i have a fairly substantial tray under the engine. Then i have one down the LH & RH sides. Other than that, the core looks fairly unprotected.

Thanks again for your replies, love your appetite for this stuff! :)


If you look in my signature....the link to all of my "how to guides".....masses of stuff is not fitted to all models even though most will if the same base mechanicals are used....ie rear multilink suspension, 2wd...
 

Munstertel

Passed Driver's Ed
Location
United Kingdom
Car(s)
R-Line Edition
If you look in my signature....the link to all of my "how to guides".....masses of stuff is not fitted to all models even though most will if the same base mechanicals are used....ie rear multilink suspension, 2wd...
Cheers Dave, I've looked through. Some great information you have put together there. Really well laid out too. Feel like i can select some real improvements to my car here depending on what cash/time i have available to me :) To start i have ordered the Harmonic dampener from Audi this morning and i will fit it on Monday :)

Quick question for yourself or anyone that has experience, when i go to dampen and sound insulate the floors, the front seats need to come out. According to the manual you need a tool(probably a connector) to safety the airbag within each seat. Have you or anyone been concerned by this or is it a case that you would just be careful not to induce any static on the pins that may deploy the airbag?

Cheers :)
 

Desslok

Autocross Champion
Location
PA
Car(s)
2019 Rabbit
The airbag and seat heater can be disconnected by hand. I've removed my passenger seat several times.
Like IanCH said, disconnect the battery first.
 
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