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Robotnik123
19-11-2012, 02:10 AM
My car has failed its Warrant of Fitness (WOF) check due to a leak in the flange to the catalytic converter. The muffler shop recommends removing the whole cat' and lengths of pipe around it and substituting in a resonator box. Would removig the cat', an emissions control device give me any issues in the future with passing WOFs? Obviously we do not have emissions testing in NZ, but I thought tampering an emissions device is a WOF fail. The shop advises that it won't be a problem however. Also could there be any other issues, like with the car's computer?

The shop says putting in a resonator would cost $250, but if I really wanted I could put in a new high-flow cat' at a cost of $500 all up. I do not mind spending extra, but doing so for no reason would be silly.

Car is a 1999 Mitsubishi Legnum VR-4 with a factory exhaust. A factory standard car, with 123,000km on the clock. Car is an auto.

Subaru ETA
19-11-2012, 02:55 AM
No need to put a resonator on - just put a straight pipe in. No issue with WOF and you turbos will spool better :D

Robotnik123
19-11-2012, 04:15 AM
I understand a cat reduces sound quite a bit, so would a straight pipe make it sound louder? And would replacing the cat with a resonator as recommended keep the sound down? Not wanting to make the car sound louder.

Oblivion
19-11-2012, 04:29 AM
I dont think you will have a problem with passing a WOF, I've never had a cat converter and its always been fine at WOF time. The cars ECU wont notice either. Perhaps you could take the opportunity to upgrade the whole exhuast and remove the cat converter at the same time?

Subaru ETA
19-11-2012, 05:56 AM
It gives it a throatier sound, doesn't make it "louder"

Subaru ETA
19-11-2012, 05:56 AM
Do you have a standard exhaust on it?

Robotnik123
19-11-2012, 08:43 AM
Do you have a standard exhaust on it?

Yes, standard exhaust.

Subaru ETA
19-11-2012, 09:07 AM
In that case, just put a straight pipe in. I gained 2 psi boost when I did mine!

elnevio
19-11-2012, 09:26 AM
Another vote for a straight pipe here! :thumbsup:

exevoowner
20-11-2012, 07:16 AM
De cat pipe all the way for what they do its pointless lol

CANDEE
20-11-2012, 08:46 AM
Jan, as above just put a de-cat pipe in. By decat pipe we mean just unbolt the cat and put a piece of pipe with the same flanges in its place, doing any other work will just ruin the downpipes and the exhaust IMO. They should be able to do this for less than $100, $280 for a resonator and install is just taking the piss. Its not a Midas or something similar is it?

You wont fail a wof for noise on a std exhaust(I just took mine into vtnz with a 3" exhaust and decat pipe and had no issues at all) or the fact it isnt there... With as 12 year old cat you prob will be loosing power with it in.

elnevio
20-11-2012, 09:01 AM
Yes, forgot to mention that you can use a decat pipe from an Evo 4-6, which will bolt straight in! :)

Robotnik123
27-11-2012, 03:50 PM
Thanks for the advice, all. Went with a straight pipe. Can't notice much if any difference with regard to sound or increase/decrease in power.

Subaru ETA
27-11-2012, 06:54 PM
Have you got a boost gauge fitted?