To de-cat or not to de-cat?

[tumbleweed]

Guys,Toying with the idea of removing the cat in my E36 325 auto. She's old and if it's advisable then it may help her to breathe. Any comments? Any effects (+ve or -ve) on performance? That's the most important thing.Thx guys.

 

[Silver]

I would suggest you not to do that based on my experience on a E46 328i. I removed it and after 2 weeks I fitted it back... After removing I actually experience lost of power rather than any increase and the exhaust sounded misearable!

I consulted JFA in Sunway and he also advised me againts removal of the cat.

But not sure on your E36 325i?

 

[tumbleweed]

I would suggest you not to do that based on my experience on a E46 328i. I removed it and after 2 weeks I fitted it back... After removing I actually experience lost of power rather than any increase and the exhaust sounded misearable!

I consulted JFA in Sunway and he also advised me againts removal of the cat.

But not sure on your E36 325i?

May be different on the E46 though. Is your O2 sensor after or before the cat? I think on the E36 there may be just one before the cat so it may not affect much.

 

[LCP]

On the other hand, I read somewhere before that a cat is only effective in cleaning up the exhaust gasses up to a certain number of years... 7 or so...

Replace the cat with a bullet, not a straight pipe.

 

[BiMmEr78]

I had removed it so long time ago and of coz the throttle response a bit better but its poluting the air ... hehehe ... my ride is E36 325i

 

[sesat88]

I had removed it so long time ago and of coz the throttle response a bit better but its poluting the air ... hehehe ... my ride is E36 325i

ada makan minyak ka?

 

[BiMmEr78]

same only bro ... the sound a bit loud

 

[Slide]

Did mine on my auto and did not have any problems. Fuel con is the same and power wise, didn't notice any diff, buy they say you gain 5bhp, which on an auto, u won't feel at all.

 

[tumbleweed]

Ok, for those who had removed the cat, kindly advise what kind of bullet (if there are indeed various sizes) to use. And where would I find an exhaust shop who knows modifying exhausts for UDMs. I heard horror stories about if not done right it may fry the ECU!

TIA.

 

[tumbleweed]

On the other hand, I read somewhere before that a cat is only effective in cleaning up the exhaust gasses up to a certain number of years... 7 or so...

Replace the cat with a bullet, not a straight pipe.

Well, if the previous owner has never changed it then it's way past it's useful life already. Anyway of telling if it's still functioning? However, I do (very) occasionally smell an odor like rotten eggs (although not as strong!). i've heard that it may be the cat causing it.

Yeah, I know of the bullet. But what spec (if there are any) for best performance and without loud sound?

 

[tumbleweed]

I had removed it so long time ago and of coz the throttle response a bit better but its poluting the air ... hehehe ... my ride is E36 325i

Where did you do it and how much did it cost? So I assume there were no adverse effects?

 

[BiMmEr78]

JFA and if im not mistaken 100 plus la

 

[mctnesh]

JFA and if im not mistaken 100 plus la

Interesting...can be considered

 

[LCP]

Rotten eggs... it simply meant high sulphur content in the petrol... not too sure on how to tell whether the cat is still working... sniff the exhaust, if you konk out, the cat is dead... nah, just kidding, do not follow my advise...

 

[INNOVATOR]

The title of this thread sounds like you want to castrate your car.

 

[tumbleweed]

JFA and if im not mistaken 100 plus la

All in? Including the two bullets and labor?

 

[tumbleweed]

Rotten eggs... it simply meant high sulphur content in the petrol... not too sure on how to tell whether the cat is still working... sniff the exhaust, if you konk out, the cat is dead... nah, just kidding, do not follow my advise...

hahaha... I'll just make sure I have someone with me when I do the sniffing test!

But seriously, with the same tank of gas it only happens once or twice. If it's high sulphur content I would smell it all the time, right?

 

[dungbtle]

question

just wana confirm, do e30s have catalytic converters? cos my exhaust fume stinks like mad. full of petrol smell. wats the prob? if the mixture is too rich, what can i do?

 

[LCP]

tumbleweed, the sulphur smell may not be there all the time, it depends on way too many factors that affect the combustion... temperature, air-fuel ratio, etc...

 

[LCP]

dungbtle, smells like too rich... the e30 experts here should be able to help