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Cat bypass pipe and MOTs

Posted: Fri Mar 25, 2022 10:07 pm
by David
My Nomad needs an MOT and I have a cat bypass pipe fitted which is how it came when I purchased the car back in September. The dealer has been a little slow sending me the catalyst (previous owner took a while to find it apparently) and I should have it next week.

I understand that the car will not pass an MOT without it fitted and I wondered how easy it would be to do the swap myself?

I've searched this forum but couldn't find any mention of anyone doing it on Nomads but there's lots of talk in the Atom forum where they make use of a club cat. Given how many people have used it I'm guessing it's pretty straightforward? The only pictures on that thread have expired and can't be seen hence my raising the question.

Let me know how easy (or hard!) it is if you've done it.

Thanks!
David

Re: Cat bypass pipe and MOTs

Posted: Fri Mar 25, 2022 10:23 pm
by stupot
Hi David,

It’s really easy. Remove the 6 nut and bolts holding the bypass pipe and replace with the cat. I find it helps to loosen the top nuts from the mounting bobbins that mount the silencer to give it bit of vertical play.

Stu

Re: Cat bypass pipe and MOTs

Posted: Sun Mar 27, 2022 9:49 pm
by David
Am pleased to report that it was as straightforward as you described, Stu. Thanks for your help!

Re: Cat bypass pipe and MOTs

Posted: Mon Oct 03, 2022 2:47 pm
by BlueIn2Red
Is it confirmed it won’t pass the MOT without the cat? My just acquired car appears to have passed three MOTs without one…

Re: Cat bypass pipe and MOTs

Posted: Mon Oct 03, 2022 3:14 pm
by John Scherrer
It won't pass a legit MOT test !

Are you sure the previous owner didn't take it to Ariel for service and MOT?

They fit a CAT before taking it for its MOT test.

Re: Cat bypass pipe and MOTs

Posted: Mon Oct 03, 2022 5:27 pm
by BlueIn2Red
Interesting, thanks. Mine wasn’t done through Ariel no. Do you happen to know if it fails because of the pure emissions numbers, or simply because the cat is absent when it should have one?

Re: Cat bypass pipe and MOTs

Posted: Sat Oct 08, 2022 9:39 pm
by atomiser
Definitely fails on emissions. CO and probably HC. Both idle and fast idle - or at least on mine (K20Z4 s/s)

Depending on what the cat looks like I.e. looks like a cat bypass then it will probably fail on visual inspection as well

Re: Cat bypass pipe and MOTs

Posted: Sun Oct 09, 2022 1:08 pm
by BlueIn2Red
Just a warning for Nomad/2.4L owners - the gaskets used for the cat section aren't metal as (I believe) on the 2.0L, so there is less chance of being able to re-use them as they might well fall apart on (dis)assembly ... mine certainly did, so with my MOT due on Wednesday I hope the factory are as efficient as usual in getting new ones out to me!

Re: Cat bypass pipe and MOTs

Posted: Tue Oct 25, 2022 8:13 pm
by GavM
Just gone through this process and Cat replacement was easy. Remember to check headlight alignment, i got lucky. Also hydraulic only handbrake won't suffice. Good luck