catalytic converters - is there a law?

[entscheidend 0]

I want to know if there is a law around Cats - Can you remove them or not?

I have heard that vehicles manufactured after 2000 need to meet EU2 or something...

I searched LTNZ and cannot find anything, Testing stations say "cut them out" its ok.

Does anyone know, or is this another thing like our German plates where only 1 in 10 cops will fine you for it....

[antil33t 90]

I don't think we need them here.

But some modern cars it's not a good idea to remove them, as they have sensors which adjust the fuel/air.

Glenn or someone will probably explain it to you better.

[*Glenn* 854]

If a vehicle has pre cat and after cat oxygen sensors... the short answer is "NO" you "CAN'T" remove them.

If the system has pre cat only "YES" you "CAN"

LTSA was thinking of bringing in legislation that required that vehicles fitted with cats must have new cats fitted if they fail, but haven't done so as yet.

There are aftermarket high flow cats available, some work, some don't. We haven't had any succes with E46 318i's and some of the cats on BMW 6 cylinder & 8 cylinder motors have the cats built into the manifolds. Audi & Mercedes also do this.

[entscheidend 0]

If a vehicle has pre cat and after cat oxygen sensors... the short answer is "NO" you "CAN'T" remove them.

If the system has pre cat only "YES" you "CAN"

LTSA was thinking of bringing in legislation that required that vehicles fitted with cats must have new cats fitted if they fail, but haven't done so as yet.

There are aftermarket high flow cats available, some work, some don't. We haven't had any succes with E46 318i's and some of the cats on BMW 6 cylinder & 8 cylinder motors have the cats built into the manifolds. Audi & Mercedes also do this.

Thanks Glenn, just what I was looking for - its a 96 740 with Pre Cats only, Cats are ratting like marbles

Edited October 10, 2009 by entscheidend

[*Glenn* 854]

Just get Pitstop or Midas to fit a couple of bullet or Coby type resonators

[entscheidend 0]

If I just straight pipe it will it be too loud / droney?

It will still have the OEM Y resonator, muffler/silencer at back in place.

Edited October 10, 2009 by entscheidend

[hotwire 352]

If I just straight pipe it will it be too loud / droney?

It will still have the OEM Y resonator, muffler/silencer at back in place.

Yep, with straight pipe replacement will be slightly louder & a little droney - I have done this before on one of these for a customer. Not excessive though:-

If you don't want more noise - go for what Glenn has suggested. I would suggest a fluted type bullet resonator as quietest & to mimick the cats

[entscheidend 0]

For better HP gain am I better to: (in place of the OEM cats)

1. Resonator

2. High Flow Cat

3. Straight pipe

Keeping in mind there will be the Y resonator, stock muffler/silencer for back pressure.

[Grant 4]

Just get Pitstop or Midas to fit a couple of bullet or Coby type resonators

Glenn had this done for me in my old 328i - it was great to get rid of the rattling cats!!

Cheers

Grant

[hotwire 352]

For better HP gain am I better to: (in place of the OEM cats)

1. Resonator

2. High Flow Cat

3. Straight pipe

Keeping in mind there will be the Y resonator, stock muffler/silencer for back pressure.

I would say minimal difference, if noticeable, either way. I have no experience with hi flow cats though

[Wom 0]

If I have pre-cat only and remove the cat and put a resonator in there in place of the cat ... is this going to make the catalytic convertor check symbol on the dash light up?

[*Glenn* 854]

If I have pre-cat only and remove the cat and put a resonator in there in place of the cat ... is this going to make the catalytic convertor check symbol on the dash light up?

If yours has cat sensors...you modify the cat sensor wires. Some dont have them

[Wom 0]

ok cheers mate

[entscheidend 0]

Guys - I have taken the cats out and replaced them with Coby resonators.

There is no difference with sound or performance - is that normal??

It is however - better with gas - Im getting 26MPG around town!!

Edited October 22, 2009 by entscheidend

[hotwire 352]

Guys - I have taken the cats out and replaced them with Coby resonators.

There is no difference with sound or performance - is that normal??

It is however - better with gas - Im getting 26MPG around town!!

Yep, normal to sound the same - cats due to their makeup will act as a resonator but a little more restrictive

Would expect better consumption figues because of this.

May not notice performance difference but if compared on a Dyno - it would no doubt show a slight gain.

[entscheidend 0]

I have noticed the unrestricted flow is making the rear OEM muffler / silencer rattle quite bad. I need a new exhaust to cope with the quicker flow of exhaust now?

Are there Remus boxes somewhere I heard for $500?