Firewall insulation options

eriknetherlands

eriknetherlands

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As I'm tearing down my car, one of the last parts to come off were the firewall insulation parts.
My parts are quite damaged, and I'm looking to replace them, so I looked into various options, as the BMW part is no longer available.

As my parts are quite disintegrated, I couldn't tell if they are 2 or 3 parts, but this is how they looked when glued back together:
Front:
20250313_232043.jpg

Backside:
20250313_232018.jpg


Top part is definitely one part (removed and placed backside pointing upward):
Bottom part was broken into pieces, and the right side was already missing on my car:
20250223_132610.jpg


Bottom part with the ALU heatshield removed to preserve for possible re-application on new part.
20250223_132759.jpg
20250305_102542.jpg

These parts are made of a cast PU (polyurethane), they are not made from a stamped foam sheet material as can be concluded from the skin forming, the various thickness, and the 3D shape of the part. It also has a hatched pattern of horizontal and vertical lines running about 4mm's apart on most of the surface:
firewall insulation lower part detail.jpg

Here's a picture from @deQuincey showing a clean & perfect OEM top part Sound insulation #51481810724, also showing the hatched pattern for reference:
1741874205318.png

As I want to replace it, I'm looking for the most accurate part to buy.

Now these questions come up:
- Where they originally 2 or 3 parts?

This is how it looks on the RealOEM (parts books copy): 2 parts:
first drawing shows #4, Sound insulation #51481810724 being the upper section. And a 2nd image with #6, sound insulation dash panel #51481811933 being the lower section (eventhough drawn on top)

1741866442977.png
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Available sources of repro parts show various options:
CS-werke has repro's available in 3 parts: (400 euro in total - status March 2025)
1741866875177.png

bottom left side:
1741873049954.png
1741866898022.png


OIL's Design has 2 parts:
1741864917579.png


Walloth show 3 parts, of which only the bottom left is available currently for 178 euro (status March 2025)
Top:
1741864577800.png


Bottom right and bottom left: (for LHD cars)
1741864693267.png
1741864720857.png


I have also seen images of a piece which scratches easy - it appear to me to be a sandwhich of a foam with heavy, dark grey 2 mm thick sheet.

- What do you have, and if it's one of the Retro parts, what's your opinion?
- I am a sucker for originality, so if anyone has an original BMW produced one - Please PM me.
 

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You forgot Christoph at CS-WERK, he offers also three parts plus the pedalbox insulation BMW_E9_Repro_Schallschutz_2022_01-324x324.jpgTeil_21_1_de_BMW_E9_Schallschutz_Stirnwand_BKV-324x324.jpgTeil_22_1_de_BMW_Schallschutz_Stirnwand_Kruemmer-324x324.jpgBMW_E9_Repro_Isolierung_Fußhebelwerk_01.jpg
Also available for RHD

Thomas
 
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I've been looking from some options to make it myself, As I've scavenged the Alu heat shield form my original part.

20250313_232535.jpg

I found this sample material at a local foam store it is a light PU foam with a skin laminated to it. Quite thin and although sold as acoustic material, it's likely suboptimal. Is only available as continuous sheet, so i practiced making some shape into it.
It doesn't quite have the hatched pattern, but with the small hexagons it does make a nice link to the hexagon pattern on the other damping material on the inner fender tops:
20250311_193644.jpg
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I installed the firewall product from CS-Werk (link) and am happy with the result.

For the foot pedal insulation I purchased from W&N and do not recommend that product sourced from them It is made with a stiff rubber rather than the soft foam insulation. If I had it to do over again I would source from CS-Werk also (link).

1756412493942.jpeg
 
here are the options that i know of for the bottom pieces and the top piece. the top piece may still be available from BMW, but it is expensive.

1. CS Werk - if you want to go this way, i have the big piece - still in the packaging for 100 bucks plus domestic shipping
1756412335525.png

1756412335543.png


2. there is coupeking - 300 bucks including the exhaust heat shield
1756412510328.png


3. @alprada70 sells all 3 pieces - don't have the current price
1756412665316.png
 
when i realized that the CS Werk piece and the BMW piece didn't work together, i bought the coupeking piece (without the header heat shield as i already had one). it installed just like the coupeking picture shows ... and the BMW top piece works fine with it.
 
How far am I you ask....
Stuck in a swamp of choices...

I bought the original BMW part around the pedal box; it was quite stiff as well, a sort of thick neoprene. But ok, OEM is OEM, so I don't argue.

I managed to save the alu heatshield, so I'm trying to figure out how I can match (and glue) it to a new foam piece. I think I will build the part on the exhaust side + the top foam part myself using the original metal hangers again, but with new foam. I found a (too?) light polyurethane foam with a skin with a
nice pattern molded into it (see above) I think I will buy half a square meter from it, and shape it myself.
the top part is supposed to have that bulge in the middle; only CS Werke has that bulge, the others do not, but then CS Werke's material isn't very close to original (but I never held it in my hands, so could be wrong there)

The original foam used for the top piece and behind the heatshield is a peculiar type; it was a cast polyurethane that forms a textured skin.
I think none of the sources use anything like it. In the repro's I see only stamped sheet material, so it has 'open' sides. And for material, what I can make out from the scarce pics is material that looks like closed cell rubber (neoprene or EPDM) foams.

Bmw's repro of the top piece from a few years ago was even different ; it was a sandwich of heavy (quartz filled) scratch sensitive rubber-like layer with a soft foam backing.

I'd pay up for an 1970's original part, just to silence the procrastination....
 
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rsporsche said:
here are the options that i know of for the bottom pieces and the top piece. the top piece may still be available from BMW, but it is expensive.

1. CS Werk - if you want to go this way, i have the big piece - still in the packaging for 100 bucks plus domestic shipping
View attachment 207638
View attachment 207637

2. there is coupeking - 300 bucks including the exhaust heat shield
View attachment 207641

3. @alprada70 sells all 3 pieces - don't have the current price
View attachment 207642
Click to expand...
If you have the top piece, that would be awesome. I'd gladly buy from you. I'm looking to do this before/while installing a strut top brace so the top makes sense. The bottom... I may leave for later, or not at all as it looks like hoses need to disconnect and parts need to come out. Anyway, that's a problem for later, and probably installs best from under the car.

I sent you a PM
 
Minivansomeren said:
If you have the top piece, that would be awesome. I'd gladly buy from you. I'm looking to do this before/while installing a strut top brace so the top makes sense. The bottom... I may leave for later, or not at all as it looks like hoses need to disconnect and parts need to come out. Anyway, that's a problem for later, and probably installs best from under the car.

I sent you a PM
Click to expand...
I installed my CS Werk top part earlier this year (with my strut brace out obviously) and it works fine, good quality, good fit - can recommend it.

I left the the bottom pieces for another time as they require the car on a lift at a minimum and much more fiddling, if not an empty engine bay.
 
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