Any Known problems with a removed Catalytic converter

[Strap]

Hey all,
Im gonna remove the cat on my e34 525i m50tu , because im starting to get the rotten egg smell after some hard driving, not all the time just if i really jump on it for a couple mins , the muffler shop pointed straight to the cat and said 600.00 usd ,, i think i will spend 20.00 on 2 small straight pipes instead as there is no emissions testing where i am , but i want to make sure im not gonna hurt the car? any info would be great ..

Thanks Strap

[BigKriss]

Hey all,
Im gonna remove the cat on my e34 525i m50tu , because im starting to get the rotten egg smell after some hard driving, not all the time just if i really jump on it for a couple mins , the muffler shop pointed straight to the cat and said 600.00 usd ,, i think i will spend 20.00 on 2 small straight pipes instead as there is no emissions testing where i am , but i want to make sure im not gonna hurt the car? any info would be great ..

Thanks Strap

no harm done to the car at all. Go for it.

[Rory525]

Please post a result if you do it as Im thinking about it just now.

Would like to know how it sounds and if it performs better...

Thanks
Rory.

[Bill R.]

pollution... the sulfur smell does not indicate that the cat is bad, there are numerous factory service bulletins stating this... the sulfur smell indicates that your running gas with high levels of sulfur, try buying at a better gas station instead.

Hey all,
Im gonna remove the cat on my e34 525i m50tu , because im starting to get the rotten egg smell after some hard driving, not all the time just if i really jump on it for a couple mins , the muffler shop pointed straight to the cat and said 600.00 usd ,, i think i will spend 20.00 on 2 small straight pipes instead as there is no emissions testing where i am , but i want to make sure im not gonna hurt the car? any info would be great ..

Thanks Strap

[Strap]

Thanks all and thanks bill r also,
I didnt know about the other items regarding the smell, the gas im getting is rated @ 95 but im stuck in asia so there are only 4 different stations to choose ( brands ) around im using the exxon , as i cant find mobile, sun or shell, .
i think im gonna dump the cat anyway and see if i get a small increase in power.but i will also change fuel this tank before i dump it.
Thanks again Strap

ps: bill , im in asia , not at home in the states. they dont do any emissions or inspection for that matter here. just pay the yearly fee. I would not even consider it if i was home. jersey emmisions sucks..

[genphreak]

Thanks all and thanks bill r also,
I didnt know about the other items regarding the smell, the gas im getting is rated @ 95 but im stuck in asia so there are only 4 different stations to choose ( brands ) around im using the exxon , as i cant find mobile, sun or shell, .
i think im gonna dump the cat anyway and see if i get a small increase in power.but i will also change fuel this tank before i dump it.
Thanks again Strap

It'll stink like hell without a cat. Any half-serious cop would book the moment they are travelling behind you in the traffic. They'll get you for having a faulty cat let alone no cat at all. I'd only consider it if the cat were bad (read very old). You'll get more power out of a new o2 sensor and other bits I suspect... a new cat is expensive, so if you remove it, make sure you don't wreck it, you might want to put it back...

[BigKriss]

It'll stink like hell without a cat. Any half-serious cop would book the moment they are travelling behind you in the traffic. They'll get you for having a faulty cat let alone no cat at all. I'd only consider it if the cat were bad (read very old). You'll get more power out of a new o2 sensor and other bits I suspect... a new cat is expensive, so if you remove it, make sure you don't wreck it, you might want to put it back...

Does it really smell that bad, what about de-gutting the cat. Since it's rare to do emissions testing in Australia and it has to "look" like you have a cat, could I get away with this?

[genphreak]

Does it really smell that bad, what about de-gutting the cat. Since it's rare to do emissions testing in Australia and it has to "look" like you have a cat, could I get away with this?

Most people gut them if they do it (so it's harder to get caught as the fines are HUGE). In Aus our fuel is low-sulfur, however I can't stand rotten egg gas personally, it leaves a bad smell everywhere you go. Imagine droppng the gf off and everyone thinking you or she dropped one as you open the door for her... I mean, its really not very practical for a small gain.

On crumby cars the gain is more, but since Motronic gets things reasonably right I guess the cat is quite finely tuned to the engine. I doubt you will get 10HP gain at WOT, but I am sure someone like Bill or Whit could go a better guess than me...

I'd hazard to say the gain is nil when running part-throttle (ie most of the time), unless you've 'charged your engine and the exhaust has become a serious restriction. Nick

[Rory525]

I dont really see why it should smell? Ive been behind cars lots of times with no cats and theres no smell at all.

And I can legally remove mine here , as cars made sometime in either 1992 or 1993 onward had to have them fitted by law.. and once fitted they had to retain them.

Mine is a 1991 car and so its legal to take it off

[genphreak]

I dont really see why it should smell? Ive been behind cars lots of times with no cats and theres no smell at all.

And I can legally remove mine here , as cars made sometime in either 1992 or 1993 onward had to have them fitted by law.. and once fitted they had to retain them.

Mine is a 1991 car and so its legal to take it off

That's a good point. I'd check the ETK for any differences in cam, injection and ECU on cars built across those dates first though... Nick