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I had another look at my car.

 

Having taken into account the Tesla video above, I moved the boot latch/striker plate further in. It was originally at the first in/out line and I moved it to the 2nd on each side.

 

The tailgate now needs a slightly firmer push to close it, but I can cope with that.

 

Based upon a suburban test drive inlcuding the bumpiest roads in the area, the unpleasantness of the boom/pulse effect does appear to have been reduced. It is wet, though, so it will remain to be seen if it performs well in the dry too. 

:thumbup:

 

The "thud" from the suspension over bumps appears to be a feature of the car and will be a function of the overall mass, stiffness & damping of the car system in various axes. If this could be tuned out with simple bolt-on blocks as in the Russian blog, then this could make a big improvement to the ride quality.

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From looking again at the Russian blogs, it appears that the Hyundai dampers are used to absorb energy from the vibrations in the trailing arms that are excited by the tyres before they reach the car body.

 

Bolting on dampers might work, but those may not be sized or positioned  optimally and there is always the risk that it may move the problem to another set of conditions (speed, road surface) that cause problems. 

 

It would be interesting to try it. The trailing arms would probably need to be be removed to drill the mounting holes.

 

 

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6 minutes ago, MC Bodge said:

From looking again at the Russian blogs, it appears that the Hyundai dampers are used to absorb energy from the vibrations in the trailing arms that are excited by the tyres before they reach the car body.

 

Bolting on dampers might work, but those may not be sized or positioned  optimally and there is always the risk that it may move the problem to another set of conditions (speed, road surface) that cause problems. 

 

It would be interesting to try it. The trailing arms would probably need to be be removed to drill the mounting holes.

 

 

 

I recon it could be done without removal.  Wheels off, lower shock mounts undone, drop beam enough to gain access. Done :tongueout:

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21 minutes ago, MarkyG82 said:

 

I recon it could be done without removal.  Wheels off, lower shock mounts undone, drop beam enough to gain access. Done :tongueout:

 

I'm searching the equivalent of the hyundai/kia parts, but then made by the volkswagen group. I'm sure a brand like Audi has these?

 

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43 minutes ago, cr_2dman said:

 

I'm searching the equivalent of the hyundai/kia parts, but then made by the volkswagen group. I'm sure a brand like Audi has these?

 

I've been looking through various Russian pages and, if you have decent drill bits and can get some weight behind it, some of these could be fitted from under the car. 

 

Adding dampers to the front and rear arms has to be worth a try.

 

I'm struggling to find the Hyundai/Kia parts in the UK. Yes, there must be other manufacturers that do them.

 

I wonder why it only appears to be Russians who do these things???

 

Edited by MC Bodge
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Having driven the car more, the pulse/boom has been reduced a bit by tightening the boot lid. The hard edge has been taken off it.

 

There is still the surprsingly hard thud through the car over small bumps, though.

 

Speedhumps and other big bumps are actually fine.

 

I suspect that the high speed compression damping is far too harsh. I'm wondering if a set of quality after-market dampers would make a big difference.

 

Coming from a standard suspension Mk4 Mondeo, the difference in ride quality is night and day.

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Today I visited my local carpet warehouse and bought some offcut underlay and carpet.

 

I added "platinum" carpet underlay under my space saver wheel  and under the entire lower boot floor.

I also added a piece of thick, felt-backed carpet to cover the lower boot floor.

 

Combined with tightening the boot fastening, the car is now much less unpleasant over bumpy or rough tarmac. The boom/thud appears to have been attenuated.

 

Third party review (from my 9 year old):

"Dad, your car isn't rumbling anymore"

 

I have some underlay and carpet left, so will try to install it under the rear seats.

 

 

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4 hours ago, MC Bodge said:

Today I visited my local carpet warehouse and bought some offcut underlay and carpet.

 

I added "platinum" carpet underlay under my space saver wheel  and under the entire lower boot floor.

I also added a piece of thick, felt-backed carpet to cover the lower boot floor.

 

Combined with tightening the boot fastening, the car is now much less unpleasant over bumpy or rough tarmac. The boom/thud appears to have been attenuated.

 

Third party review (from my 9 year old):

"Dad, your car isn't rumbling anymore"

 

I have some underlay and carpet left, so will try to install it under the rear seats.

 

 

 

Can you post some pictures of the trunk and carpets ?

 

I've got an appointment this monday with the dealer.

 

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It's nothing very exciting, but here is what I now have in the boot.

 

The underlay is 10mm(?) platinum foam. It looks like this: https://www.amazon.co.uk/Platinum-Underlay-10mm-Thick-Carpet/dp/B00KJI1AQG

 

The spare wheel is resting on  pieces of underlay, but I've not fully lined the wheel well yet.

 

I'm not sure how much benefit the carpet is adding, but I thought it was worth trying as it adds some weight and maybe some sound reduction.

Carpet.JPG

Rubber mat.JPG

underlay under spare wheel.JPG

Underlay.JPG

Edited by MC Bodge
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19 hours ago, cr_2dman said:

 

Can you post some pictures of the trunk and carpets ?

 

I've got an appointment this monday with the dealer.

 

The carpet dealer?

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  • 2 weeks later...

Having driven the car on a long ish journey on a variety of roads, I feel that there is almost certainly a pressure issue as well as a remaining vibration boom issue. My ears felt pressurised at various times and my 9 yo daughter mentioned, unprompted, having a headache at the same times as I felt the pressure -my wife said she hadn't noticed anything and my son didn't mention it.

 

I decided to look at the pressure relief valve and do more sound proofing earlier.

 

I could reach under the bumper to what felt like the relief louvre, but could do little else.

 

I discovered that there is a very thin, vertical panel at the rear of the wheel well below the boot latch -lt had a small piece of sound-deadening(?) material (the same as the pieces in the bottom of the wheel well) slapped on it at a jaunty angle. Tapping it produced a loud, hollow noise. As did tapping the jack/tools holder.

 

I stuck some thin, flexible plastic backed mat to the panel with strong double sided tape and then stuck some of the carpet underlay to the mat. The sound was deadened considerably when the panel was tapped. I did similar under the spare wheel and put underlay under the tool holder.

 

On three laps of my local pothole and ripple test area, the booming noise appeared to have been further reduced and the car seemed quiter.

 

If I get some more mat I will stick some to the boot floor behind the seats.

 

The pressure issue is possibly still to be addressed.

 

Ps. I've ordered some sticky D foam for the upper front doors to reduce wind noise.

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Also, as i droven around various places:

 

maybe you can confirm these:

 

1. The sound is (almost) gone when it's rainy outside. (Wet track)

2. When you ride faster the sound is less / not there, i went to the german autobahn,  when riding around 100-170, there is no vibration noises or pressure issues in the cabin. However, on the very same autobahn with stau, there was the sound again, riding around 10 to 50Km/h.

3. When you 'hear' the vibration noises, you can feel the vibrations of the chassis.

4. The sound is always worse when you are alone in the car.

 

As amazon.co.uk won't send to europe, i have to order at amazon.de:

I would be ordering the following, i'm just not sure of the extra foam):

https://www.amazon.de/gp/product/B0148HOZL0/ref=ox_sc_act_title_1?smid=AFK8WWWJF9FL6&psc=1

https://www.amazon.de/gp/product/B005JRZPMM/ref=ox_sc_act_title_2?smid=A1COJ4BGFDL9U6&psc=1

https://www.amazon.de/gp/product/B07MZP5546/ref=ox_sc_act_title_3?smid=A1I08M4GDZ4GXS&psc=1

 

The sound i'm referring to is around 30-36hz, for example (listen with quality headphones, as an iphone or ipad speakers cannot reproduce these)

 

 

 

Also, i've discovered some articles about this booming noise issue, has been researched by profs, the pro say, these sounds primarly comes from the roof and tailgate. (will lookup the exact articles later). The lack of stifness of the chassis contributes to the low tones.

So i did the test: I stamped with my fast the in the middle of the front roof and the tailgates made a noise, so i adjusted the rubber stoppers further.

 

My dealer said these vibrations/sounds are coming from the tires and suggest goodyear instead of continentals. I personally don't think goodyear makes rounder tires than continentals. (are new tires and new car)

 

And for last, i also found this forum: https://www.motor-talk.de/forum/golf-7-poltern-im-heckbereich-t4784357.html?page=132

I'm just not sure the poltern are from the suspensions or is a vibration noise, as it's difficult to discribe the sound

Edited by cr_2dman
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On 09/04/2019 at 14:56, cr_2dman said:

Also, as i droven around various places:

 

maybe you can confirm these:

 

1. The sound is (almost) gone when it's rainy outside. (Wet track)

2. When you ride faster the sound is less / not there, i went to the german autobahn,  when riding around 100-170, there is no vibration noises or pressure issues in the cabin. However, on the very same autobahn with stau, there was the sound again, riding around 10 to 50Km/h.

3. When you 'hear' the vibration noises, you can feel the vibrations of the chassis.

4. The sound is always worse when you are alone in the car.

 

As amazon.co.uk won't send to europe, i have to order at amazon.de:

I would be ordering the following, i'm just not sure of the extra foam):

https://www.amazon.de/gp/product/B0148HOZL0/ref=ox_sc_act_title_1?smid=AFK8WWWJF9FL6&psc=1

https://www.amazon.de/gp/product/B005JRZPMM/ref=ox_sc_act_title_2?smid=A1COJ4BGFDL9U6&psc=1

https://www.amazon.de/gp/product/B07MZP5546/ref=ox_sc_act_title_3?smid=A1I08M4GDZ4GXS&psc=1

 

The sound i'm referring to is around 30-36hz, for example (listen with quality headphones, as an iphone or ipad speakers cannot reproduce these)

 

 

 

Also, i've discovered some articles about this booming noise issue, has been researched by profs, the pro say, these sounds primarly comes from the roof and tailgate. (will lookup the exact articles later). The lack of stifness of the chassis contributes to the low tones.

So i did the test: I stamped with my fast the in the middle of the front roof and the tailgates made a noise, so i adjusted the rubber stoppers further.

 

My dealer said these vibrations/sounds are coming from the tires and suggest goodyear instead of continentals. I personally don't think goodyear makes rounder tires than continentals. (are new tires and new car)

 

And for last, i also found this forum: https://www.motor-talk.de/forum/golf-7-poltern-im-heckbereich-t4784357.html?page=132

I'm just not sure the poltern are from the suspensions or is a vibration noise, as it's difficult to discribe the sound

That sounds familiar.

 

The conclusion to the Golf forum thread is that nobody knows what can be done to stop the noise.

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Well, I have done full sound deadening  (almost) to my car. Roof made a significant difference on estate. They have 2 quite large peaces of felt glued to the  roof panel under lining. Felt is fluffy and airy and has no weight(about 10-15 mm thick).

In my opinion it contributes very little to sound deadening/vibration damping.  Unfortunately I am unable to assess how noisy roof is by itself because I had whole interior out and did the floor pan at the same time.

Edited by TonisT
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27 minutes ago, TonisT said:

Well, I have done full sound deadening  (almost) to my car. Roof made a significant difference on estate. They have 2 quite large peaces of felt glued to the  roof panel under lining. Felt is fluffy and airy and has no weight(about 10-15 mm thick).

In my opinion it contributes very little to sound deadening/vibration damping.  Unfortunately I am unable to assess how noisy roof is by itself because I had whole interior out and did the floor pan at the same time.

Interesting.

 

I had noticed that the roof lining was very light and the roof metal also appeared to be very thin.

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Roof lining is normal. I had ford focus before and lining was very similar.

However  roofs metal is thin and has large area where there are no bends or supports so vibrates very easily. 

 

Other thing that was significant difference was suspension. I had "sports" suspension which was lower and stiffer. Went back to normal height and used ww golf dampers front and rear and lesjöfors springs rear. Rear springs made significant difference in boominess  while driving.

Unfortunately compared to my old 2006 ford focus this car has tendency to ring so to speak.

I did focus noise insulation also and it was much easier to get desired result because it was just loud noise  and it didn't ring.

Octavia has much more ringing to it and therefore I have to do doors again. I damped only inner surface of doors under the door cards. However front doors still ring when I shut them compared to rear doors because they are larger and the metal is very thin. So I need to do front doors again and also dampen the outer sheet metal.

One more thing I did and had noticeable difference is static vibration dampers on suspension parts. Those things work.

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1 hour ago, TonisT said:

One more thing I did and had noticeable difference is static vibration dampers on suspension parts. Those things work.

What dampers did you use and where did you attach them?

 

The lightweight body does seem to resonate at an unpleasant frequency. The car is and feels much lighter than my previous car, which has its advantages, but also disadvantages.

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I had these in front and rear

33316770851 - just google this number (bmw vibration damper)

They fit without any drilling. I do have non independent rear suspension.

I didn't use them in front at the end because the way the fit in front took away some ground clearance but they work pretty well (no drilling what so ever just bolt on)

in front struts I have these like here (Ford cuga ones) although I had to modify them little to fit them

https://www.drive2.com/l/7433929/

 and rest is basically like this

https://www.drive2.com/l/9795116/

except that i have the bmw ones next to rear wheels (no drilling needed) and the kia/hunday ones on the cross beam (no drilling needed)

Front is like the last link now because ground clearance but I feel that BMW ones were bit better because they were right next to wheel.

I also added the same kind of dampers like on the front axle to the strut top mounts. Had to remove one of the mounting brackets.

 

I would like to find something to fit to top mounts of rear struts but haven't found anything that is easy and fits yet

Edited by TonisT
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1 hour ago, TonisT said:

I had these in front and rear

33316770851 - just google this number (bmw vibration damper)

They fit without any drilling. I do have non independent rear suspension.

I didn't use them in front at the end because the way the fit in front took away some ground clearance but they work pretty well (no drilling what so ever just bolt on)

in front struts I have these like here (Ford cuga ones) although I had to modify them little to fit them

https://www.drive2.com/l/7433929/

 and rest is basically like this

https://www.drive2.com/l/9795116/

except that i have the bmw ones next to rear wheels (no drilling needed) and the kia/hunday ones on the cross beam (no drilling needed)

Front is like the last link now because ground clearance but I feel that BMW ones were bit better because they were right next to wheel.

I also added the same kind of dampers like on the front axle to the strut top mounts. Had to remove one of the mounting brackets.

 

I would like to find something to fit to top mounts of rear struts but haven't found anything that is easy and fits yet

That's great. What and where did you bolt them to? Do you have photos?

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No but I'm going to change to summer tires soon. I can take some pictures then. But basically for the rear axle dampers there just happened to be stamped holes where I could bolt them on and had enough room.

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8 minutes ago, TonisT said:

No but I'm going to change to summer tires soon. I can take some pictures then. But basically for the rear axle dampers there just happened to be stamped holes where I could bolt them on and had enough room.

Thanks. I'll have a look at my beam.

 

Did you fit one or more to the rear? Did you attach them to a moving part of the beam?

Edited by MC Bodge
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Rear axle was so that BMW ones bolted next to wheel and spring and the kia/hyundai ones went just to the middle of beam where the oval holes are. They need bigger washers than normal. I installed 2 pcs one on each side of U shape. One would be enough I suspect But I got over exited while ordering parts.

BMW ones just needed long bolt, washers and nyloc nut. Washers stacked so that the heavy damper outer shell can vibrate independently and wont touch up with beam.

Red circle of mounting hole I mounted it on, on the picture. And it fits very well above the beam not under so no clearance issues.

r-beam.PNG

 

At the front the problem with BMW one was that I could not mount it on top of the wishbone but underneath so you can imagine that when driving down from the sidewalk on small angle it might scrape the curb. However here was the hole I mounted it. I did not test it on top because it got really close to sway bar and I was unable to test if it would clear everything on both extreme suspension positions.

f-beam.PNG

That's why I ended up with dampers as in the seat link. Would have preferred BMW ones in front also because in my opinion they worked bit better as they were closer to wheel.

Edited by TonisT
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