Catalyst removal?

Alan Fisher · Post by **Alan Fisher** » Mon Sep 27, 2004 9:05 pm

Seeing as there is no legal requirement for one in NZ I was wondering if
anyone had any experience of removing it and replacing it with a "test pipe"
or "cat bypass pipe" as they are sold in the US and UK respectively?

Power? Torque? Noise?

Worth bothering?

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poison · Post by **poison** » Mon Sep 27, 2004 9:22 pm

I'd be keen to know this also, I rang City Garage in Auckland for a price and
they said don't bother, and so did the local muffler shop (Al's mufflers).
Shows these are credible businesses when they are honest about such things.

Gazza

SLYDIT · Post by **SLYDIT** » Mon Sep 27, 2004 9:30 pm

as of next year there will be new emmissions laws and
testing. your car will fail its wof if it hasnt got
the cat in .
I was talking to a muffler guy the other day and he
said he was going to make a killing putting cats back
in to boy racer cars that had them removed.
If you do remove it you will notice a gain in HP but
your exhaust note will be raspier, put a little hot
dog muffler resonator in there

Alan Fisher · Post by **Alan Fisher** » Tue Sep 28, 2004 9:01 am

I have to say that is the conclusion I keep coming to - but the promise of
possible "free power" keeps luring me back to examine the issue. Was
wondering if it might make more difference to mine as it is a 1994
"transition" 1.8 with the 1.6 downpipe and smaller cat...

Here are reviews I found on mx5parst.co.uk of people who had bought theirs:

http://www.mx5parts.co.uk/product_revie ... cts_id/461

Also - dont know how much they would charge for shipping but last time I was
in the uk I got a replacememt power aerial mast from them - something I
hadnt been able to find elsewhere.

[...]

Jeff · Post by **Jeff** » Wed Sep 29, 2004 8:16 am

Miata magazine did an engine dyno and concluded it was worth "less than
3hp" - I assume that means 2.49hp

Fletch · Post by **Fletch** » Wed Sep 29, 2004 11:51 am

I hollowed out my cat...

result... no noticeable power gain, and a really nasty ringing raspy
noise...

So I replaced that with a straight pipe for only $40 at the local muffler
shop...

result... noise not as bad, but still not acceptable to me (and still no
extra power)

So I replaced that with a small resonator for $70...

result... noise back to how it was at the beginning, with $110 spent and no
extra power!

A clogged up cat can rob you of power, but a working one doesn't seem to...

I also now get a black filth on my rear bumper that takes a lot of polish
and sweat to remove.

Personally, I wouldn't do it again.

Fletch.

Alan Fisher · Post by **Alan Fisher** » Wed Sep 29, 2004 1:25 pm

Thanks alot

I reckon that pretty much secures the future of my cat!

Cheers

Alan

[...]

Lou Girardin · Post by **Lou Girardin** » Wed Sep 29, 2004 8:39 pm

Well that's hard to specify seeing that the Govt hasn't set emission levels
yet. More unfounded rumour I think.
Lou

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