I Want To Remove My Cats. Can?

[centurion]

Re: I Want To Remove My Cats. Can?

Nope. Nothing at ALL, i took out my mid-cats and replaced them with a stainless steel mid pipe. Took out my original headers and installed a aftermarket one. All sensors intacted and no check light.

Now Shaaz, tell me then how come. Because, there are sensors before and after the Cats, and these measure adherence to emissions legislation. (it's the law).

Now you take away the cats, and these things measure anyway. Should they now detect that there is no more cat and put the engine into limp-home mode?

Strange, right? Have you wondered?

It's mandatory to put the engine light on actually, it doesn't just write into the OBD2 log.

 

[Rastaman]

Re: I Want To Remove My Cats. Can?

Well, i don't have any cats or precats and i have no check lights and all my O2 sensors are still intact so ... for me no problem ..

Same goes for me as well ! :nehnehhh:

 

[Rastaman]

Re: I Want To Remove My Cats. Can?

Maybe u dun get it yet, lemme try n make it clearer y there is no check light. Simply coz we all have installed after mkt headers which come with 2 holes to fit the 02 sensors. These are way in front of the precats so there is no problem even if u decat.

 

[shaaz]

Re: I Want To Remove My Cats. Can?

Maybe u dun get it yet, lemme try n make it clearer y there is no check light. Simply coz we all have installed after mkt headers which come with 2 holes to fit the 02 sensors. These are way in front of the precats so there is no problem even if u decat.

YUP YUP !!!!

 

[louis]

Re: I Want To Remove My Cats. Can?

i've never understood why the CEL doesn't come on either. aren't they suppose to register different oxygen levels pre-cat and post-cat under normal operating conditions? if both sensors are now placed pre-cat, wouldn't they register similar oxygen levels and hence trigger a fault code?

 

[shaaz]

Re: I Want To Remove My Cats. Can?

Honestly same here, but when i did it and no lights came out, couldn't care less why it did not come on.. hahaaha.

 

[MRacer77]

Re: I Want To Remove My Cats. Can?

as i always say as long as it works, don't really have to understand how it works...

 

[shaaz]

Re: I Want To Remove My Cats. Can?

Well said........

 

[BlackStealth]

Re: I Want To Remove My Cats. Can?

Thats why those automobiles engineers work their arse off for our added leisure!

They get paid and we pay. So fair deal.

 

[centurion]

Re: I Want To Remove My Cats. Can?

hey man, everybody here don't understand why CEL don't come on and lead me on to think that you do, then suddenly everybody admit don't understand ....

I did some more research last night because this thing bothered me, and here is what I think now....

The post cat sensors are actually located OUTSIDE the path of the exhaust. The precat sensors are intact.

The post cat sensors are measuring the oxygen level of ambient, OUTSIDE the exhaust, which is perfect without emissions.

Without an air mass sensor, all this PASS. No problem. No CEL.

Check your car and see. The oxygen sensor is OUTSIDE your exhaust path. Just check.

 

[MRacer77]

Re: I Want To Remove My Cats. Can?

Wow. Did not know that, interesting.

 

[shaaz]

Re: I Want To Remove My Cats. Can?

hey man, everybody here don't understand why CEL don't come on and lead me on to think that you do, then suddenly everybody admit don't understand ....

I did some more research last night because this thing bothered me, and here is what I think now....

The post cat sensors are actually located OUTSIDE the path of the exhaust. The precat sensors are intact.

The post cat sensors are measuring the oxygen level of ambient, OUTSIDE the exhaust, which is perfect without emissions.

Without an air mass sensor, all this PASS. No problem. No CEL.

Check your car and see. The oxygen sensor is OUTSIDE your exhaust path. Just check.

Ok, i go check for you one of these days, you know exactly where tho?

 

[louis]

Re: I Want To Remove My Cats. Can?

hey man, everybody here don't understand why CEL don't come on and lead me on to think that you do, then suddenly everybody admit don't understand ....

I did some more research last night because this thing bothered me, and here is what I think now....

The post cat sensors are actually located OUTSIDE the path of the exhaust. The precat sensors are intact.

The post cat sensors are measuring the oxygen level of ambient, OUTSIDE the exhaust, which is perfect without emissions.

Without an air mass sensor, all this PASS. No problem. No CEL.

Check your car and see. The oxygen sensor is OUTSIDE your exhaust path. Just check.

are you referring to aftermarket setups or stock? in any case, the last i checked on my stock setup, this was not the case. iirc, the last i looked at a set of aftermarket headers, this was not the case either as it had 2 bungs welded on to allow the Oxygen sensors to plug into the exhaust path.

and all the above cars who have no CEL with aftermarket headers still use air mass sensors so there must be another reason.

 

[centurion]

Re: I Want To Remove My Cats. Can?

Ok, i go check for you one of these days, you know exactly where tho?

Dunno man, sorry. Remus exhaust, Tubi ... all different.

 

[louis]

Re: I Want To Remove My Cats. Can?

stock setup:
RealOEM.COM   BMW E85 Z4 2.5i LAMBDA PROBE FIXINGS

aftermarket setup:

 

[centurion]

Re: I Want To Remove My Cats. Can?

sheez then,.... back to google.

 

[Jonnybravo]

Re: I Want To Remove My Cats. Can?

YO... Long Zhong Eh Brother...

U all discuss this discuss that... CEL... PreCat, PostCat... PussyCat.... I hear until cock sian oredi.

Let's Simplify the Qn.

If were u, would

1. REMOVE COS WILL MAKE MY CAR FASTER + NOISIER (OH YEAH!)
2. DUN WAN TO REMOVE COS WASTE MONEY ($$$$$)

Pls Vote!

Aniwae my car is stock. no mods to engine. only lower + mod aircon. HHAhaHAhAhAha....

Jon

 

[centurion]

Re: I Want To Remove My Cats. Can?

My vote: dun remove. I'm OK to have huge V8 car with huge CO2 emissions but not so much the NO and SO2 emissions, as long as you are within the law. BUT once you take out the cats, you are against the law, and screwing around with the environment. We are already in deep environmental crap, do your bit.

 

[louis]

Re: I Want To Remove My Cats. Can?

i suspect it may be a regional thing.

for Z4s at least, there are differences depending on whether its rhd or lhd. for right hand drive cars, we have 2 sets of cats, a smaller secondary set integrated into the exhaust manifold and the primary cats integrated into our "mid pipes". these primary cats are located after both lambda probes.

left hand drive Z4s only have one set integrated into the exhaust manifold; they have resonators mounted onto the mid pipes instead of another set of cats.... yet both LHD and RHD cars have similar mounting points for both lambda probes.

since the primary cats for RHD cars are actually located after the sensors, it is reasonable to assume that the 2nd set of sensors, ie the "post-cat" ones, on the RHD cars are either calibrated differently from their LHD counterparts, serve a different function altogether or have been disabled and are a redundant feature on RHD cars.

the link between the redundancy and lack of CEL with aftermarket headers is pretty straightforward. as for different calibration, given that the sensors are located before the primary cats, i would imagine that it's been programmed to allow for higher oxygen levels and hence a greater tolerance towards aftermarket headers that have the cats removed.

again, i don't know for sure; the above is my postulation only.

 

[louis]

Re: I Want To Remove My Cats. Can?

YO... Long Zhong Eh Brother...

U all discuss this discuss that... CEL... PreCat, PostCat... PussyCat.... I hear until cock sian oredi.

Let's Simplify the Qn.

If were u, would

1. REMOVE COS WILL MAKE MY CAR FASTER + NOISIER (OH YEAH!)
2. DUN WAN TO REMOVE COS WASTE MONEY ($$$$$)

Pls Vote!

Aniwae my car is stock. no mods to engine. only lower + mod aircon. HHAhaHAhAhAha....

Jon

if you're not interested in the technical bits, just remove lor..... it'll be louder for sure.... and you can pretend any warning lights that may come on actually mean "sports mode on"