Retrofit a catalytic converter

[Vez010]

Hi,

Has anyone retrofitted a catalytic converter to their E30? I’ve recently had an OEM exhaust fitted so not looking to change that, but possibly fitting a cat if possible.

Thanks in advance.

[BenHar]

Why?

Ben

[Vez010]

As much as I love my car, I can’t stand the fumes. Bit of a contradiction owning a classic but if there’s a possibility retrofitting a cat can make a difference then I’d be interested to know more.

[DanThe]

The fumes shouldnt be so bad you want to fit a cat, unless the engine is not running properly

[Vez010]

The car could be running rich and there are a few hoses that could do with changing. I’ll give that a go but would still be interested to know if anyone has attempted a cat retrofit.

Thanks for your input.

[Tzantushka]

*raises hand slowly*

Here in AUS catalytic converters are legislated - you're supposed not supposed to remove or modify the system.
Each state has different rules, but not as strict as annual emissions / smog checks like elsewhere in the world.

My '88 320i was fitted with a cat and needed replacement.
Genuine costs were eye watering both local and imported alternatives.

The OE exhaust system had the integrated cat converter & resonator, so it was going to be hard to find an aftermarket solution for a 30+ y.o. part for a reasonable cost.
Ended up going to a local exhaust shop where they Frankensteined the front part of the resonator / cat housing (with the angled entry point) onto a aftermarket cat and kept the dual pipe exit.
Don't have a picture for you...

Works ok - but if I had my time again (and wanted to comply & protect the environment) I'd buy a good used OE cat /resonator section, cut it open & replace the monolith and TIG weld it back.
Or go for a full AM replacement with a cat and hope it doesn't drone too much.

[flybynite]

The car could be running rich and there are a few hoses that could do with changing. I’ll give that a go but would still be interested to know if anyone has attempted a cat retrofit.
Thanks for your input.

As above you need to get the engine running right first, if you try to put a cat on a car as a band-aid for an engine problem then you are likely to poison the new cat before you get going. Having a knackered cat in the exhaust of a bad running engine will just make the problem worse

Where are you smelling it? All cars smell a bit if you shove your nose up the exhaust but if you are getting the smell in the car then you have a problem that needs fixing.

Dont know where you are and what engine but some of them were not designed for cats and were not sold in markets like the US for that reason.

Drove one of the earliest E30s daily for 10 years and never felt the need myself.

Don't you like the small of napalm in the morning??