De-cat

So in chatting to an exhaust specialist today he had a look at the work I had done to the tezz.

He pop's his head up and says "oh thats a no-no" going on to say that the Altezza does not like have the catalytic converter removed and was my engine light coming on?

It does not, however it got me wondering if there is any substance to this?

Old wives tail?

sounds a bit like bollocks to me...
I've got an RS-R mid pipe(ie no cat) and it runs better than with the cat in

Im no expert on Catylist Converters, I wasn't even aware that the altezza had one, but my experience with them is that they do more bad than good. My understanding is that they are there to make the car more environmentaly friendly by collecting carbon . In my Suzuki Grand Vatara which is an awful vehicle, the Converter has craped out twice, all my research has led me to the answer that the best option is to cut the thing out of the system ( which I would do if it wasnt a lease vehicle) this seems to have given the best result to the people who have tried it.

Only Issues I can see is that it will make the vehicle less emmision friendly, which will only be a problem if they start testing vehicle emmisions.

if u rarely drive the car or its really for track i'd say go with decatting, which is what i've done in the past

For something that gets driven daily i don't think its a good idea
1. smells really bad for the person driving behind u
2. u'll get a lot more black crap spitting out the exhaust so if u park in a garage like i do...garage will be really dirty
3. maybe not for u guys. but illegal in some area
4. in the end..it is there for a reason..don't wanna do more harm to mother nature

I am considering gettin a custom exhaust made up with extra test pipe. so when i track i use the test pipe, then normally i'll have a hiflow cat in there.

i can see winston's name in this thread for a while..must be typing a loooong post

No the cat is not for collecting excess carbon

Its designed to convert hydrocarbons, carbon monoxide and nitrogen oxides to water carbon dioxide and nitrogen. Its an EPA device used to remove extremely harmful pollutants into our atmosphere (the kind that causes smog and acid rain). If your cat is full of carbon then your AFR is all over the shop or your burning oil.

The reason its bad to remove it (aside from environmental impacts) is your engine is not tuned to cope with the removal of that restriction in your exhaust which can cause issues to the flow of gas out of your exhaust valves and into your ports.

You should never de cat a road car and if the cop asks to take a sample of your exhaust and fails and you are asked to get an emission test you will be slugged with a huge fine.

Doesnt matter where you live, if your country follows EPA regulations which NZ does as does most western countries its illegal.

It is actually illegal in NZ to remove the cat, although most workshops and specialists will do it for you anyway ($$$)

PS it turns the car into a super twangy note!

Here was mine back in 2006/2007, full OEM Exhaust with only the cat removed

Sounds rancid in my opinion

I had mine cut out last year I haven't noticed any downside and am yet to see the check engine light. Just passed a vtnz wof with it

Just my 2c

Ha i did not know thats its illegal to remove them.

Your WOF check must be as dodgy as our pink slips then...

You might not notice a difference because it would be neglegible at best but the damage it might do to your valve train would go unnoticed till something breaks...

If your oxy sensor is in your cat then your engine light will come on, if it is in your manifold downpipe then it wont matter....

Yeah, our WoF system is pretty lax. Cats have only been a legal requirement since February in NZ, and emissions testing for wof isn't compulsory (yet). Most places just check to make sure it's not too smokey and thats about it...

By the way VTNZ WoF's are the strictest in N.Z.

You miss quoted me dude. I said they are as dodgy as our pink slips ffs if your going to quote me dont take it out of context!

WOFs are much harder to get n NZ than in Aussie.

Its like NZ was back in the 60's, but now NZ would write half the Aussie cars off the road.

I LIKE the Aussie system!

Closer to our blue slips?

So this begs the question..
Nick I know there are "high flow" cats so what can you drum up out of the gooogle machine?

Here is hoping for 2.5" options

Got some options avail in stock! Flick me an email and I'll take a look for ya Monday

Yeah I don't notice the car performing badly without it.
But trying to keep the car totally legal so I'll look at the options

Posted this under the wrong thread but here goes...

I'm still confused as to if the cat is required or not but reading into this, its not?
True or False.

My main driver is keeping the car legal for insurance purposes.
Check the bit I put in bold.

http://www.transport.govt.nz/legislation/V...ns-and-Answers/

#32. What will happen if I repair or modify the vehicle?
If a vehicle's exhaust emissions equipment is modified or repaired, the repair must enable the vehicle to continue to comply with the standard to which it was built. If there is doubt, a vehicle may be required to undergo an emissions test to demonstrate compliance. This provision applies only to vehicles that are required to comply with a specific standard when they enter the New Zealand fleet, it does not apply to vehicles that are already part of the in-service fleet.

After a quick skim read I take it to mean it is illegal to remove cat, but only if your car was imported after Feb 2008.

Thats what I was thinking....^

Stolen from another forum where a mate posted who actually works for NZTA.......

Cat requirements clarified on page #3 (note that the wording on page #2 appears to be incorrect, stating first reg 2012 rather than I assume the intended 2010 statement).

So it is a requirement that has changed, so older experiences will differ.
http://www.lvvta.org.nz/documents/infoshee...rd_Revision.pdf

This was posted on 30 March this year

Thanks very much for this BT
The flow chart makes things much clearer to understand.
No cat required unless I'm reading into this wrong .
"Was vehicle first reg’d in NZ after 1 May 2010?"

Mine being a 98 I should be safe.
First reg: 56,399 2008, June 17th WOF inspection

Not if done with AU steal, its the Jap steal that will give you the twang in the high rev's. I have AU coby's on mine which while they are heavier they absorb that high rpm twang the tezz gives.

Mines barely noticeable for possibly and extra few kg's.

That was with NZ/Australian Mild Steel, and NO resonators, just a straight pipe.
Hard to compare one with and without a resonator as it changes the note all together

Too true