Removing catalytic converter

[andya 0]

Hi,

I drive a 318i E46 98 with apparently what has been diagnosed as a broken catalytic converter.

From what i understand under current legislation (which will most likely change early next yr tho) I can elect to remove the cat converter entirely and put in a kobe resonator or the like in instead. I have asked around and got various quotes - from bmw workshops the cost ranges up to over $1000 but midas/pitstop etc can do it for around $250ish. I suspect that at bmw garages they would be installing bmw parts thus the higher prices.

Has anyone out there done this type of conversion. Mechanics have told me that it might be a fraction louder with the cat removed - my only concern now is will it make any problems for the O2 sensors?

In the meantime the converter is rattling away worse than ever and I have heard that they can block up completely and basically prevent the car from starting. One last question - without the cat my exhaust emissions will still be pretty good I would suspect as the engine is fairly low on miles but even with the rattling (if i can bear it) and the fact that no warning lights have yet come up on the dashboard telling me there is an exhaust issue (if there are such warning sensors) do I even need to get it fixed. I mean if it passes muster on emissions testing say at WOF then would you even bother fixing it? (the noise is annoying but I can block it out with the radio etc).

One last question too - does anyone happen to have a 318i E46 1998/99 Owners manual and/or cd business stereo manual? Mine are both in Japanese. If some one does and would like to help me out I would much appreciate it.

Cheers,

Andy

[hotwire 352]

Hi,

I drive a 318i E46 98 with apparently what has been diagnosed as a broken catalytic converter.

From what i understand under current legislation (which will most likely change early next yr tho) I can elect to remove the cat converter entirely and put in a kobe resonator or the like in instead. I have asked around and got various quotes - from bmw workshops the cost ranges up to over $1000 but midas/pitstop etc can do it for around $250ish. I suspect that at bmw garages they would be installing bmw parts thus the higher prices.

Has anyone out there done this type of conversion. Mechanics have told me that it might be a fraction louder with the cat removed - my only concern now is will it make any problems for the O2 sensors?

In the meantime the converter is rattling away worse than ever and I have heard that they can block up completely and basically prevent the car from starting. One last question - without the cat my exhaust emissions will still be pretty good I would suspect as the engine is fairly low on miles but even with the rattling (if i can bear it) and the fact that no warning lights have yet come up on the dashboard telling me there is an exhaust issue (if there are such warning sensors) do I even need to get it fixed. I mean if it passes muster on emissions testing say at WOF then would you even bother fixing it? (the noise is annoying but I can block it out with the radio etc).

One last question too - does anyone happen to have a 318i E46 1998/99 Owners manual and/or cd business stereo manual? Mine are both in Japanese. If some one does and would like to help me out I would much appreciate it.

Cheers,

Andy

Andy,

You can at this stage still remove the converter & replace with a coby or similar (a fluted type unit is best) -this type vitually replicates the converter in its noise absorbing ability. I fit this type at work in this situation. No doubt the BMW quote is for replacing the converter. The sensor in front of the converter is to indicate overheating exhaust (blocked converter) -bringing on a red idiot light. This will come on if the internals collapse & block the exhaust. This will happen before you notice a drivabilty issue probably. Due to the anoyance factor i would get it sorted -it will get worse before collapsing. Wont leave you standed though. Wont affect O2 sensor. Emissions will still be ok for WOF but not as good as original.

Re manuals: Ask BMW parts - they are usually quite reasonable new

Cheers Grant

[hybrid 1043]

What ever you do, dont remove the oxygen sensors down stream. The computer can't run the engine properly with out them.

There is a very restrictive piece BMW put in-between the cat and the second muffler. This was for emmissions and minor noise reasons.

Best power mod you can make to an e46 cheaply is change the pipes from the cats to the tip into a twin pipe config.