E12 m535 exhaust system same as 635csi 1980

[PV-ALPINA]

Hi,

I wonder if there is any difference between E12 M535i exhaust system and series one 635 CSI (78-81)?

[86_6series]

Never an M on the E12 chassis.

[Ralph in Socal]

I’ve asked Zinnocoupe to comment. He recently accumulated the necessary parts to put E12 M535 exhaust on his e12. He did tell me they’re different.

Ralph

[GRNSHRK]

The E12 M535i indeed existed as a Euro model

Equipped with an M90 engine, front air dam, nice seats, stripes, Mahle wheels, rather rare model

As far as the exhaust fitting an '80 Euro 635, while I don't have a definitive answer, I would think that yes, it would fit

[zinnocoupe]

Hi Gentlemen, To answer this question properly I'll have to post some links to Realoem etc. There are actually two different sets of downpipes for either car and on the M535i two small center mufflers and on the 635csi one long center muffler. I know for a fact the two diff sets of down pipes are not interchangeable between systems, I know because I bought one set that didn't work with the long center muffler meant for the 635csi. Add to this that some of the parts of BOTH systems are NLA I now have a complete system for the 635csi which I am pretty hopeful but not totally sure will fit my 77 530i. I'll post more when I have time to add links to realoem and also photos of the two systems which actually look quite different but I think will fit either car. You just cant mix and match. The only possible snag I see is possibly the hanger just above the diff not lining up perfectly. So to answer your question Johan, "I think it will work". Hope this helps, more to come

[bpoliakoff]

Euro 635 with M90 is a 2" system from the down pipes back. Would guess an M car the same. Real OEM is not clear on everything but I believe it is 2" or 50mm

[86_6series]

I stand corrected. I looked up US in Realoem. Never thought of the Euro.

[zinnocoupe]

OK so after taking another look at realoem, it looks to me that there are two different systems that could have come on both the e12 M535i and the euro 635csi

First I looked up M535i, this is the page on realoem:
https://www.realoem.com/bmw/enUS/partgr ... 535i&mg=18

It shows both systems as being used on both cars

Next is the 635csi page. This page also shows all the systems used on the series 2 cars, but the two systems with the round can shaped rear muffler appear to be used on both the the m535i and 635csi.
https://www.realoem.com/bmw/enUS/partgr ... 5CSi&mg=18

The only big difference I see is with the three piece system , the center muffler has an extra hanger were the two piece system doesnt.

Ive recently collected all the parts for the system which is also on my 79 euro 635. My e12 needed a new exhaust to replace the thermal reactors and the loud monza rear muffler and I looked around at options. Most of the stock e12 system is available but I was hoping for something a little more free flowing so I opted for the Euro 635 system. . It took a while to find the down pipes , but I finally think I have everything. Its catless being euro and 50mm all the way from the manifolds to the tips. The two mufflers didnt cost much more than the stock e12 mufflers would have cost from the dealer. The downpipes came used from ebay Germany. They were lost in transit during covid but finally showed up. One of them is NLA . The reason I went with what I think is the 635 system vs the m535i system is the e12 center muffler is also NLA.
Heres pics of the parts all put together to check fit etc


[url=https://flic.kr/p/2jBdA2P][url=https://flic.kr/p/2jBh5uC]jBMG29AWRCu0wI0pFU4blg_thumb_319b by Dave Grayson, on Flickr
[url=https://flic.kr/p/2jBdzJ4]

Anyways PV-ALPINA to help answer the question, I think the m535i system will fit your 635. Im doing the opposite on my car, hoping it all works.

Bert, which mufflers do you have on your 635? Im guessing its the two piece system with the long single front muffler.

This is my take on all these parts , any input anyone else has I welcome.

[PV-ALPINA]

OK so after taking another look at realoem, it looks to me that there are two different systems that could have come on both the e12 M535i and the euro 635csi

First I looked up M535i, this is the page on realoem:
https://www.realoem.com/bmw/enUS/partgr ... 535i&mg=18

It shows both systems as being used on both cars

Next is the 635csi page. This page also shows all the systems used on the series 2 cars, but the two systems with the round can shaped rear muffler appear to be used on both the the m535i and 635csi.
https://www.realoem.com/bmw/enUS/partgr ... 5CSi&mg=18

The only big difference I see is with the three piece system , the center muffler has an extra hanger were the two piece system doesnt.

Ive recently collected all the parts for the system which is also on my 79 euro 635. My e12 needed a new exhaust to replace the thermal reactors and the loud monza rear muffler and I looked around at options. Most of the stock e12 system is available but I was hoping for something a little more free flowing so I opted for the Euro 635 system. . It took a while to find the down pipes , but I finally think I have everything. Its catless being euro and 50mm all the way from the manifolds to the tips. The two mufflers didnt cost much more than the stock e12 mufflers would have cost from the dealer. The downpipes came used from ebay Germany. They were lost in transit during covid but finally showed up. One of them is NLA . The reason I went with what I think is the 635 system vs the m535i system is the e12 center muffler is also NLA.
Heres pics of the parts all put together to check fit etc


[url=https://flic.kr/p/2jBdA2P][url=https://flic.kr/p/2jBh5uC]jBMG29AWRCu0wI0pFU4blg_thumb_319b by Dave Grayson, on Flickr
[url=https://flic.kr/p/2jBdzJ4]

Anyways PV-ALPINA to help answer the question, I think the m535i system will fit your 635. Im doing the opposite on my car, hoping it all works.

Bert, which mufflers do you have on your 635? Im guessing its the two piece system with the long single front muffler.

This is my take on all these parts , any input anyone else has I welcome.

Super! Thank you for the extremely thorough answer!