De-cats and MOT. Pass or fail?

2.7 V6 30v biturbo - 251bhp
2.7 V6 30v biturbo - 261bhp
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stapo69
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De-cats and MOT. Pass or fail?

Post by stapo69 » Sun Nov 02, 2008 8:41 pm

Just looking at the pictures of the de-cat pipes s4-99 has fitted in the "custom exhaust" thread. I had the same set-up made while I had the rest of my system made, so main cats removed getting ready for more power in the future, straight through pipe after the flexy joints then centre and rear box after, seemed easy to have it done at the same time as some pipework was going rotten, however I still have the pre-cats at the moment.

My question is how will it fair come MOT time, emissions wise? Will it pass ok, guess it'll be best being up to running temp to start with?

I have a re-mapped ecu fitted, but I also have the standard ecu, will I be better off refitting the standard one?

Thanks in advance to all.

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S2tuner
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RE: De-cats and MOT. Pass or fail?

Post by S2tuner » Sun Nov 02, 2008 9:00 pm

regardless of what ECUs you have, if your car is totally decatted, it will NOT pass any MOT

s4-99
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Re: RE: De-cats and MOT. Pass or fail?

Post by s4-99 » Sun Nov 02, 2008 9:31 pm

S2tuner wrote:regardless of what ECUs you have, if your car is totally decatted, it will NOT pass any MOT
I think he's asking if it will pass an MOT with just the pre-cats???

I dont think it will with just pre-cats, but i'm sure other member's will confirm.....
Hmmm, its fast but is it fast enough!!!

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RE: Re: RE: De-cats and MOT. Pass or fail?

Post by S2tuner » Sun Nov 02, 2008 10:22 pm

It will pass with just precats, but ideally you want to get rid of the precats and keep the main cats on, turbos like that much better )

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stapo69
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RE: Re: RE: De-cats and MOT. Pass or fail?

Post by stapo69 » Sun Nov 02, 2008 10:29 pm

As long as it passes for now I'm happy, MOT is soon. I know it's not the ideal set-up, but it'll do me for the time being, was just easier and cheaper at the time this way round as the cat side of the flexi was rotting through. Can't do any harm for now? Prob swap for some bigger downpipes with just hi-flow main cats in the future.

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RE: Re: RE: De-cats and MOT. Pass or fail?

Post by jimbo1234567 » Mon Nov 03, 2008 12:30 am

get rid of all the cats and find a freindly mot center

s4-99
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Re: RE: Re: RE: De-cats and MOT. Pass or fail?

Post by s4-99 » Mon Nov 03, 2008 4:30 pm

jimbo1234567 wrote:get rid of all the cats and find a freindly mot center
2nd that..... :sekret:
Hmmm, its fast but is it fast enough!!!

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stapo69
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RE: Re: RE: Re: RE: De-cats and MOT. Pass or fail?

Post by stapo69 » Mon Nov 03, 2008 6:27 pm

I've tried! No one round here will budge, bloody VOSA computerised tests, got away with it for years previously on various decatted cars, but no one local will do it anymore.

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RE: Re: RE: Re: RE: De-cats and MOT. Pass or fail?

Post by jimbo1234567 » Mon Nov 03, 2008 7:33 pm

where abouts are you?

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ogg14
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RE: Re: RE: Re: RE: De-cats and MOT. Pass or fail?

Post by ogg14 » Mon Nov 03, 2008 7:39 pm

So if you remove the precats and leave the main cats on will it still pass the MOT...

Thanks

Andy

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RE: Re: RE: Re: RE: De-cats and MOT. Pass or fail?

Post by jimbo1234567 » Mon Nov 03, 2008 8:00 pm

yes

s4-99
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Post by s4-99 » Mon Nov 03, 2008 8:15 pm

You could get your main cats made up so you can slip them on for the MOT then slip them off when it's done. Hour's work each swap, so gotta be worth 2 hours of your time for the reward :thumbs:

Image

Image

Image
Hmmm, its fast but is it fast enough!!!

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ogg14
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Post by ogg14 » Mon Nov 03, 2008 8:21 pm

Thanks for that...

It was just that i was enquiring today about a new powerflow exhaust for my 1999 pre-face lift s4... £580

I will be going down this road... using my cats as a spare for MOT time...

Thanks guys...

Andy

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Post by s4-99 » Mon Nov 03, 2008 8:30 pm

That price is for a full system from the flexi pipes back i take it, and your cats made up to fit on & off?
Hmmm, its fast but is it fast enough!!!

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stapo69
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Re: RE: Re: RE: Re: RE: De-cats and MOT. Pass or fail?

Post by stapo69 » Mon Nov 03, 2008 8:32 pm

jimbo1234567 wrote:where abouts are you?
I'm in Stamford, near Peterborough.

And I no longer ave the main cats, bugger.
Last edited by stapo69 on Mon Nov 03, 2008 8:35 pm, edited 1 time in total.

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