Rear seat sound insulation part number

[karter16]

Hi all,

Hoping to crowd-source some knowledge here. I've pulled up the butyl-type sound deadening under the rear seat as it was all broken up as I understand happens. The part number on what I removed is 51488204055 however when I check on realoem and on schmiedmann they both indicate that that part number didn't come on my M3, and that 51488252759 (which appears to be a wool/fabric type item) is the correct part number. (or in fact did both come on the car and I'm missing the wool/fabric part).

Any advice? my understanding is that the butyl-style item is what came on our cars, but realoem doesn't list it as a superseded part or anything, just states that it's a standard 3 series E46 part, but did not come on the M3.

Keen for any thoughts/knowledge/advice. (also I know I'm probably better off to go with an after-market solution, but the purpose of this thread is to figure out what's going on between these two part numbers).

Thanks!

[heinzboehmer]

51488204055 came on my car. 51488252759 did not (or at least it wasn't there when I bought the car).

[Casa de Mesa]

For what it's worth... go here:

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/55462-dumb-question-thread-no-flaming-allowed?p=172796#post172796

After that OEM Crayon-like smelling stuff disintegrated into nothingness, I bought a couple of yoga mats at Walmart, cut them to size and put the seats back in. It helps quite a bit with noise reduction. Much more so than that original stuff.

[Obioban]

I’d be curious how well the e82 part fit. BMW is using a new, very light fabric material for this purpose, that also looks like it would have better longevity.

[karter16]

I’d be curious how well the e82 part fit. BMW is using a new, very light fabric material for this purpose, that also looks like it would have better longevity.

Interesting - the e82 looks to be quite a different shape, but it does look fairly similar in terms of material as 51488252759.

Looking at weight:

51488204055 (the original item on my car): 2.83 kg
51488252759 (the item realoem quotes): 1.67 kg
51487058127 (the e82 equivalent part): 1.16 kg

I'm kind of interested in getting 51488252759 to see what it's like.

[Obioban]

Interesting - the e82 looks to be quite a different shape, but it does look fairly similar in terms of material as 51488252759.

Looking at weight:

51488204055 (the original item on my car): 2.83 kg
51488252759 (the item realoem quotes): 1.67 kg
51487058127 (the e82 equivalent part): 1.16 kg

I'm kind of interested in getting 51488252759 to see what it's like.

Please update us, if you do!

[nahvkolaj]

I replaced it with mass-loaded vinyl from Second Skin. Seems to do at least as good a job as stock. The yoga mat looks like a good absorption addition.

[bmwfnatic]

Interesting - the e82 looks to be quite a different shape, but it does look fairly similar in terms of material as 51488252759.

Looking at weight:

51488204055 (the original item on my car): 2.83 kg
51488252759 (the item realoem quotes): 1.67 kg
51487058127 (the e82 equivalent part): 1.16 kg

I'm kind of interested in getting 51488252759 to see what it's like.

The 759 looks like a very nice piece to be honest, good shape, but I have never seen it on a car.

[karter16]

The 759 looks like a very nice piece to be honest, good shape, but I have never seen it on a car.

Yeah it does, it looks to have liftable flaps so you can access the covers to get to the fuel pump, etc. seems to be nicely moulded. Shipping to NZ is painful cause of it's size so have reached out to a couple of places in country to see if I can get a reasonable price.

[heinzboehmer]

Please update us, if you do!

You should steal the one from your 128 to test fit on the M3

[Obioban]

You should steal the one from your 128 to test fit on the M3

That’s no small effort— both cars have a baby seat in the back.

[Bry5on]

You should steal the one from your 128 to test fit on the M3

You should steal the one from your 128 to test fit on the M3

[heinzboehmer]

You should steal the one from your 128 to test fit on the M3

Lol I knew that was coming. Haven't taken the rear seat apart in the E82, but don't think it should be too difficult. Might take a look later

[tlow98]

You should steal the one from your 128 to test fit on the M3

beat me to it!

[heinzboehmer]

Well it sorta fits:



There's a raised portion in the middle that flattens out easily and some trimming is required for clearance around the seat back and belts. But overall fits pretty decent.

Also weighed in at 2 lbs, so slightly lighter than what realoem says. Will only get lighter after trimming