Foam Insulation: Is It Good?

I've been thinking about soundproofing my Passat 35i. Does foam work well for soundproofing, or is it not very effective? I was planning to put it in the doors (gluing it to the paneling and behind the window, i.e., towards the outside). Also, I'm going to insulate the paneling itself with the foam. Would that make a difference, or would it just be a waste of time? How about covering the trunk with that fuzzy fabric, like in a Golf 4?

Best regards, WarLord.

Hi,

If you use materials like these, please remember that they should be flame-retardant.

Are there any legal regulations regarding this? And in what ways is this otherwise important?

Best regards, WarLord.

Bitumen, which is also used in the car audio industry, can also be very helpful.

"However, bitumen is also very heavy... you could check here; there are Golfs that have been stripped of their standard soundproofing to save weight. Is the Passat that noisy that it would be worth it?"

Yes, bitumen is heavy, and I have some mats inside to accommodate the front system.

'Advantages: The doors no longer make a loud noise when closing, but instead produce a quiet 'thump.' During operation, the interior noise has noticeably decreased, solely due to the door insulation.'

The disadvantage is the weight and the amount of work involved (cutting, fitting, warming, shaping, gluing).

Best regards,
Sure, here is the translation of the text from German to English:

'Richi' is a German word that means 'request'. It can also be used as a verb, meaning 'to request'.

Here are some examples of how to use the word 'Richi' in a sentence:

* Ich habe einen Richi für ein neues Auto. (I have a request for a new car.)
* Ich möchte einen Richi stellen. (I would like to make a request.)
* Bitte Richi. (Please request.)

I hope this helps!

@matthiasTDI96

Well, my main concern is the wind noise, which I want to eliminate. The engine noise isn't as much of a problem.

@Richi Rich

Well, I didn't want to use bitumen for these reasons. Also, I'm not concerned about structural noise damping, but rather airborne noise, and bitumen probably won't help much with that. What would be a compromise solution for me would be engine bay soundproofing mats.

Best regards, WarLord.

'I had them in my last car. The sound insulation is good for high frequencies (wind noise), as long as the sound has to pass through the foam mats and can't bypass them.'

However, I would like to point out one thing: Foam is an excellent water reservoir. Once it gets wet, it retains moisture for a long time (rust!). And you will inevitably have water in the door. In my old car, it didn't matter, but the speed at which rust developed on the areas insulated with foam surprised me.

PS: I used to get some from a company near me that manufactures wheel loaders; they used it for cabin insulation. That section would end up in the waste and was free.

Regards,
-Private

So, bitumen on the door frame and foam insulation behind the vapor barrier?

Best regards, WarLord.

It sounds like the best possible solution, in my opinion.

@ Warlord

When you're gluing bitumen, please don't forget the area between the outer panel and the side impact protection. That's the area that tends to rattle the most on the 35i...

... and when gluing, please don't block the water drainage openings at the bottom of the doors, otherwise you'll soon have doors with a water reservoir and a certain amount of splashing .

Best regards, Rainer.

'No, I don't close those things, because then the water would stay inside.'

@DocSnydor

What is the side impact protection? Some colleagues told me that it's located on the B Holmen.

Best regards, WarLord.

The side impact protection is a metal bar located in the door, roughly at the halfway point. You'll see it when you look inside the door. It's attached with two screws (at least in the G3). I removed it to make it easier to apply the bitumen pads.

Regards,
Private.

It looks the same on my Passat! However, I don't know if it comes out, because it didn't for me...
But if you're only concerned about wind noise, you can save your money on the mats, because they don't reduce it at all.
These mats are only meant to prevent resonances from the surface to which they are applied. In reality, this is mostly done in the car audio field...