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Hi there, I have a 07/1978 built 323i, and have an entire new exhaust system sitting here from W&N, and can't figure out how the downpipes are supposed to work.

On the front (and rear) of my center muffler, there is a triangular flange on both pipes. But on the downpipes, only the FRONT downpipe has a matching triangular flange.

The REAR downpipe just ends plain, with NO flange.

I thought I had received the wrong part, but I looked closely at the parts diagram, and other photos of these parts on ebay and such, and they also seem to match.

these for example:

http://www.ebay.com/itm/NOS-E21-BMW-320 ... 1498245148

Is it intended that I am supposed to have someone weld on a proper flange as part of the install? I can't think of any other explanation.

I looked at the blue book on this, and it doesn't say a thing about it.

thanks and regards
David

Okay.. I figured this out on my own..

I see now that there is a different sealing ring for the non-flanged headpipe, that must crush down and seal when you tighten the clamp against it..

Too bad I don't have one of those (the matching triangle flange)

So much for the "installation kit" that I thought would contain everything I needed.. (It contained the downpipe gaskets, but no copper nuts!)

regards
David

Answered before anyone else could would claim the missing parts though if these are offered as an installation kit

Jeroen wrote:Answered before anyone else could would claim the missing parts though if these are offered as an installation kit

Everything so far has actually been due to me filling in the blanks incorrectly or missing information.. The car has been a (mostly enjoyable) puzzle all along so far.. Work on one thing, figure something out, discover another thing..

In this case, the previous exhaust (partially missing) was a custom job from the downpipes back, so I didnt have any of the original pieces or hangers left except for the manifolds themselves.

BMW lists a part number 18211175764, which walloth & nesch carry, and show a photo of on their website https://www.wallothnesch.com/anbausatz- ... 02-13.html .

in this case, I got exactly what was pictured in the kit, but hadn't realized I was missing a number of additional pieces that are supposed to be re-used when replacing the exhaust

namely 3 pieces of the center muffler hanger and 3 pieces of transmission/headpipe bracket, and the triangular 3-bolt flange.

The copper nuts were also my own misunderstanding, they must be stainless, and match the photo as well; (just not my memory or the old ones I removed).