OE catalytic converter

General conversations about BMW E28s and the people who own them.
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ahendra
Posts: 42
Joined: Aug 02, 2012 3:05 PM
Location: Redmond, WA

OE catalytic converter

Post by ahendra »

Looking for a CARB compliant cat for an automatic 535i. Price for a direct fit after market (magnaflow or DEC) cat is insane at $1600 was only $800 few years back. OE cat for an auto is NLA but the manual variant is still available. Any idea what is the difference there. Can a manual cat be easily modded to work with an auto? Thanks All.
austin8753
Posts: 1444
Joined: May 16, 2010 1:37 AM
Location: Portland, Oregon, USA

Re: OE catalytic converter

Post by austin8753 »

the only difference, from the auto to manual catalyst, is the placement of the exhaust hanger. will totally bolt right on and be functional, though.
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: OE catalytic converter

Post by Mike W. »

You know, I've got a couple of older BMW factory cats, neither of which is good. I keep thinking I should take them in for scrap metal or sell them for cat scrap, then I see stuff like this. I know I could cut one apart, weld in an aftermarket, weld the shell back up and go in for smog. For a damned lot less than $1600.

FWIW I'm seeing California 535i cats for $350 for DEC and $800 for Magnaflow from the big A. Both appear to be 2 in, 1 out (at least according to the pic) and just the cat, not the downpipes. They may be 5 speed versions, but as Austin said, the difference is in the support bracket. But a possible option at least.
ahendra
Posts: 42
Joined: Aug 02, 2012 3:05 PM
Location: Redmond, WA

Re: OE catalytic converter

Post by ahendra »

Image

If I read Austin correctly the bracket circled in red needs to be cut and re-weld at the right location to secure the cat.
ahendra
Posts: 42
Joined: Aug 02, 2012 3:05 PM
Location: Redmond, WA

Re: OE catalytic converter

Post by ahendra »

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I was wrong earlier. Apparently the hanger placement are very different. To install a 5 speed cat to an automatic ignore the 5 speed hardware (item# 4-9) and weld the bracket(cut from the old cat) to the new cat. Have I have missed anything else?

Thanks All.
austin8753
Posts: 1444
Joined: May 16, 2010 1:37 AM
Location: Portland, Oregon, USA

Re: OE catalytic converter

Post by austin8753 »

ahendra wrote: Oct 10, 2021 2:17 PM Image

Image

Image

I was wrong earlier. Apparently the hanger placement are very different. To install a 5 speed cat to an automatic ignore the 5 speed hardware (item# 4-9) and weld the bracket(cut from the old cat) to the new cat. Have I have missed anything else?

Thanks All.
correct. you remove the mounting bracket from your old, automatic catalyst, and move it over to the new catalyst, welding it in the same position, that it was located on your old unit.
ahendra
Posts: 42
Joined: Aug 02, 2012 3:05 PM
Location: Redmond, WA

Re: OE catalytic converter

Post by ahendra »

Once again thanks All for the input. Now I feel confident knowing it can be done.
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