Pressure Buffeting - Has anyone experienced it?

[cucubits]

I'd like to resurrect this thread for a little while. I'm in the middle of various experiments to stop this buffeting in a 2016 facelist S.


I have been adjusting the existing stoppers and even the plastic plates on the body side but, while better, I feel I can do more to stop it completely.

For reference, first we're looking at my wife's Beetle's hatch. Similar size, yet there's zero buffeting noise on the same roads where it's the worst in my S. What's immediately noticeable is if I tap with my hands on the outside of this hatch, when closed, on both cars, it sounds and feels much more solid on the Beetle. Next we'll check the adjustment points on it. There's only two and the rubber part is much much harder than the adjusters on the Tesla. So, as @cab said, I will buy some hard rubber and replace them.

Next thing I tried is to lower the striker on the Tesla. I went almost 5 whole milimeters lower so the hatch now presses just a little better on the seal all around. This helps but the whole assembly is still not stiff enough with the existing soft rubber adjusters. Will address this over the next few days.

Could anyone tell me it this insulation looks like Tesla original soundproofing (it's the back of the body, we're looking right next to the striker). I bought the car from Tesla so of course I've got nothing on its history.

 

[Tslacg]

Best thing that resolved it for me completely was to turn my car into a true sedan. I put a body pillow over the trunk cover and blocked the air flow to prevent buffering.

Obviously blocks your rear mirror, but side mirrors and rear camera for me was better than ear popping over bumps.

Sad to hear this is still an issue..

 

[cucubits]

I'm not ready to give up rear visibility just yet.

Did some more testing in the mean time. I've set the hatch striker to the lowest possible position (I think almost one whole cm lower than it was from the factory). The hatch is still aligned with the body, maybe even a bit better now (before it was sitting a bit higher anyway). This means the whole hatch should be pressing more firmly against the seal and I don't have to unscrew so much of the rubber adjusters - which means they sit more rigidly. I do feel I'm making progress. On a road section where it was really bad, now the pressure buffeting feels much more mild.

Next step is to find some hard rubber rods to replace the body side adjusters. The factory ones are just too soft.

Any tips on sourcing small hard rubber pieces?

 

[David.85D]

Any tips on sourcing small hard rubber pieces?

mcmaster.com

 

[cucubits]

Quick progress update. I've made hard rubber stoppers instead of the softer ones but I've also discovered something which may be one of the culprits here.

First I wanted to see how well/evenly the hatch sits on the seal when closed. Quite hard to actually see this without taking off the plastic trim pieces so I thought of another way. I put a small bead of grease in various places on the seal and closed the hatch to see exactly how squished the bead would end up. No surprise, in most spots the hatch wouldn't even touch the bead. Just on the upper part (closer to the hinges) it would touch. This is even more troubling considering I had the striker set to the lowest position possible (basically the hatch should press hardest on the seal with this setting).

So yeah, I think this is why we've seen good results with taping the hatch completely. Apparently they've designed this in a rush (as many other parts of these cars). Also, similarly, we've seen good results here when someone tried to tape a rope around the section of the hatch which touches the seal.

We're going to address this by "extending" the seal contact surface on the hatch. I've ordered 1 inch wide, 1/8 inch thick hard strip which I will tape on the hatch, where it should touch the seal.

The hard rubber stoppers do help, but on my test drive on a particular road section where buffeting is always there, I could still hear it. Wasn't really surprised since I already knew then the problem with it not touching the seal properly.

PS: Hard rubber is surprisingly easy to cut with a Japanese hand saw. Lubrication helps cut it even faster.

To be continued.

 

[cab]

I don't think any of the seals make appreciable contact. I put grease on the entire seal (bit of a mess) and looked at the touch points all the way around...a think touch point over most of it. You can even "raise" the seal by pulling it up a tiny bit off the pinch weld. I think the tape acting as a seal was a red herring. Instead, I believe the blue painter's tape I put around the entire circumference served to hold the hatch in place more firmly. It is actually hard to replicate a solution that does something similar to the tape ironically.

As to the rubber stoppers, I assume they are pretty firm (i.e. can't compress them with your hands). I just used round rubber dowel.

 

[cucubits]

I don't think any of the seals make appreciable contact. I put grease on the entire seal (bit of a mess) and looked at the touch points all the way around...a think touch point over most of it. You can even "raise" the seal by pulling it up a tiny bit off the pinch weld. I think the tape acting as a seal was a red herring. Instead, I believe the blue painter's tape I put around the entire circumference served to hold the hatch in place more firmly. It is actually hard to replicate a solution that does something similar to the tape ironically.

As to the rubber stoppers, I assume they are pretty firm (i.e. can't compress them with your hands). I just used round rubber dowel.

Yes, very firm. It was a jewelers rubber block, can't compress by hand. I wanted to experiment with a little hammer shape but I'll also try the dowel approach. It may be better since the way you shaped them, they touch more surface of the "hole" where the original ones would sit.

Next is to attempt to make the whole hatch actually press a bit on the seal by taping a hard rubber strip (1/8in thickness) on the point where it should touch the seal. Essentially mimicking the whole hatch being lower for better contact.

Something like this. It's very hard rubber, advertised as 65A. This will have to wait for a few days as I have a Mobile Tech coming over on Wednesday for another issue and he'll take a ride to hear the buffeting. I'd like to see what he says with stock setup.

 

[cucubits]

Just a quick update, more like a teaser since I don't have any results yet.

As expected the Mobile Tech who took a ride with me today said he couldn't hear anything like what I was describing. I guess I can't fault him, probably not everyone is sensitive to this particular frequency.

In any case, I proceeded to stick on the hard rubber strip for better contact with the seal. I would dare to say that it looks nice, nothing out of place. Sadly it's raining, late and I couldn't be bothered to go out for a drive tonight. I'll go out tomorrow morning and see if there's any improvement.

 

[cucubits]

For now we're going to consider this problem solved. With the rubber strip, I adjusted the striker to close the hatch as tightly as it could. A very small change makes a difference as there is a point from which it will not close it anymore. I still with it would press a bit harder on the seal but it's fine (I judged it by leaving pieces of paper on the seal and seeing how hard it is to pull them out).

Also, adjusting the 4 rubber stoppers properly is important. If I had them pressing too hard, it actually made it worse. Not sure if that is because they essentially wouldn't let the hatch press on the seal properly of some other reason.

Overall it's much better now. Only on the road sections where it used to be really bad, I can barely hear/feel some now. Probably a part of that is also only in my imagination since I've "trained" myself to expect it there.

We'll probably revisit this after I'm done soundproofing. I do plan on adding a bit of weight to the liftgate to see if we can make it a bit more solid. If I tap it on the outside, it still feels much more "rattly" and loose compared to the Beetle liftgate. This should not be the case.

 

[David.85D]

Would you please post the exact type of rubber strip you used and how you glued it...

 

[cucubits]

Sure, this is the rubber strip: https://www.amazon.com/gp/product/B07BMBTV7H (I got the 3 inch wide 5 foot long option and I cut it myself into 1 inch wide strips).

Glued it with this: https://www.amazon.com/gp/product/B07C3N86G3 (half inch roll). I can't speak about the durability of this but let's say that it's not falling off by itself. We'll see how it behaves if it gets wet.

 

[ShawnA]

Hi Cucubits,

I did not see what you plan to use for sound deadening...
I have used 3M 08840 sound deadening pads and Noico 80 mil
sound deadening mats successfully in my cars...

Good luck,

Shawn

 

[cucubits]

Hi Cucubits,

I did not see what you plan to use for sound deadening...
I have used 3M 08840 sound deadening pads and Noico 80 mil
sound deadening mats successfully in my cars...

Good luck,

Shawn

Yes, that's the general plan, Noico 80mil and MLV. Lots of useful pics in this thread: Scoob’s sound proofing before & after experiment... although I will do it myself so I probably won't be that thorough (not removing the interior). I plan on doing the doors and the trunk area.