Refitted my cat converter

[Kieran]

Suprised me this did!

I refitted the cat to my exhaust system this weekend. MOT is up soon, and I wanted to see what difference it makes to the car in terms of response, MPG and noise. It will be staying on post MOT too - I think there are other areas of the system that are a much greater restriction (I think one of the Kiwis has found this out).

To put this into context, Ariadne is standard as far as I can tell. No boost alterations, and just a HKS filter in the standard airbox. There is evidence of some other tweaks around the car (spotted a crudely terminated cable this weekend) but most look like they were removed (or stolen, more commonly) on the way from Japan to the UK.

And the results? Well, it's early days, but So far:

Noise - Slightly quieter and a slightly smoother exhaust note at idle. But nothing major.

MPG - Too early to tell.

As for performance, I reserve judgement untill the ECU and gearbox have stopped operating in eejit mode (I reset the ECU). As with my V6 Sport, I think it will take a day or two to see what effect it has.

I was surprised though by the lack of immediate change - I'll post more as I pile on the miles (In my fully Amsoil-equipped car :smug: )

[psbarham]

mine still has the cat on after the mot , and there are only 2 noticable differences that i have noticed .

the first one is the low down torque is much better (more back pressure) but the rest of the rev range is a bit lacking .

the second one is the biggest problem and not in my liking at all , its too bl00dy quite now http://www.smileypad.com/v10/Cache/Sad/No.gifhttp://www.smileypad.com/v10/Cache/Angry/Rage2.gifhttp://www.smileypad.com/v10/Cache/Angry/Rage.gif

[Kieran]

Oi! You're not licensed to use my smiley!! /pan

[Bal]

my "4" has been decatted and i must admit the tone is to much for me. gives me a frigging headache when cruising (and i've only driven it 4 times since i've bought it - today will be 5th).

i'll put the cat back on when i replace the gasket that is busted and see how i go.

[Physician]

It does seem to vary from car to car, owner to owner Kieran.

I've always said that my decat made virtually no difference whatsoever to both noise levels and performance (pre- my quad exhaust system).

Post- my quad exhaust ....... it got a tad noisier :embarasse and definitely slower 0-60 mph :embarasse

[Kieran]

Post- my quad exhaust ....... it got a tad noisier :embarasse and definitely slower 0-60 mph :embarasse

The first change I would expect ;)

The second surprises me somewhat. Whereabouts do you notice the change? Is it low down, or does it feel 'pinned back' at higher revs? :inquisiti

Intersting to see that you experienced no difference between catted and de-catted either. Mind you, your car is standard too. Perhaps it only becomes an issue as you start to wang the boost up and stuff?

[pezza]

My cat is back on too as MOT expires tomorrow....

At standard boost, initial pickup seems stronger... but it seems gutless at higher end...

The exhaust is def quieter, which is good! But I can now hear a clunking sound when I go over bumps! /grr Not sure if there is excessive play and its knocking the sides or maybe something inside the cat is bust???

After driving round on higher boost for past week tho, the difference apart from noise is errr nothing?? There is nothing lacking.. as for MPG.. well I still cant resist booting the car so cant see any change yet! /pan

Good luck to all you MOTers this week! :thumbsup: