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Mid pipe cats replaced - question

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Verinder1984
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Mid pipe cats replaced - question

Post by Verinder1984 » Tue Sep 21, 2021 7:38 am

Hi guys I’m booking my car in to have the mid pipe cats removed and replaced with sports cats.

Main reason for the mod is the make the car a little louder whilst retaining stock look.

Wanted to know if I do this mod will it bring up any errors on the dash? If so what can be done to fix the errors?

Many thanks in advance

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RedUn
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Mid pipe cats replaced - question

Post by RedUn » Tue Sep 21, 2021 12:41 pm

Should be fine with a set of sports cats :thumbsup:
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Mid pipe cats replaced - question

Post by tomscott » Tue Sep 21, 2021 12:55 pm

I have this on mine no issues 👍🏻

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Mid pipe cats replaced - question

Post by Simon 3.2M » Tue Sep 21, 2021 5:44 pm

Would here be an issue if you removed the cats in toto?
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RedUn
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Mid pipe cats replaced - question

Post by RedUn » Tue Sep 21, 2021 9:13 pm

Apart from an EML and the obvious MOT issue, no none at all...
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Mid pipe cats replaced - question

Post by Verinder1984 » Thu Sep 23, 2021 12:24 pm

Spoke the the exhaust guy he convinced me to just do a 2nd cat delete.

Cheaper, and said it won’t make the car too loud Bcus the rest of the exhaust is stock. And said will pass mot no issues.
I’m not so sure but I hope he know what he’s talking about.

If it’s loud I can always reverse it

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RedUn
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Mid pipe cats replaced - question

Post by RedUn » Thu Sep 23, 2021 12:46 pm

Verinder1984 wrote: Thu Sep 23, 2021 12:24 pm Spoke the the exhaust guy he convinced me to just do a 2nd cat delete.

Cheaper, and said it won’t make the car too loud Bcus the rest of the exhaust is stock. And said will pass mot no issues.
I’m not so sure but I hope he know what he’s talking about.

If it’s loud I can always reverse it
Are you in the UK? Our cars only have 1 set of cats... So it won't pass an mot no...
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Verinder1984
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Mid pipe cats replaced - question

Post by Verinder1984 » Thu Sep 23, 2021 2:55 pm

RedUn wrote: Thu Sep 23, 2021 12:46 pm
Verinder1984 wrote: Thu Sep 23, 2021 12:24 pm Spoke the the exhaust guy he convinced me to just do a 2nd cat delete.

Cheaper, and said it won’t make the car too loud Bcus the rest of the exhaust is stock. And said will pass mot no issues.
I’m not so sure but I hope he know what he’s talking about.

If it’s loud I can always reverse it
Are you in the UK? Our cars only have 1 set of cats... So it won't pass an mot no...

Yes uk z4mr. Hummmm. I think I can fix emissions issue with mot not overly worried. Will it flare up any errors on dash? And with induction would you say it worth remapping.

I noticed with only induction it has flat spots between 1-2k rpm sometimes.

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Mid pipe cats replaced - question

Post by AndyBeech » Thu Sep 23, 2021 3:30 pm

Verinder1984 wrote: Thu Sep 23, 2021 2:55 pm
RedUn wrote: Thu Sep 23, 2021 12:46 pm
Verinder1984 wrote: Thu Sep 23, 2021 12:24 pm Spoke the the exhaust guy he convinced me to just do a 2nd cat delete.

Cheaper, and said it won’t make the car too loud Bcus the rest of the exhaust is stock. And said will pass mot no issues.
I’m not so sure but I hope he know what he’s talking about.

If it’s loud I can always reverse it
Are you in the UK? Our cars only have 1 set of cats... So it won't pass an mot no...

Yes uk z4mr. Hummmm. I think I can fix emissions issue with mot not overly worried. Will it flare up any errors on dash? And with induction would you say it worth remapping.

I noticed with only induction it has flat spots between 1-2k rpm sometimes.
You sure he means the Cats and not the centre x pipe part / resonator? Seen that 'straight' piped before which will give a bit more sound and not cause any issues. Straight up cat delete seems risky these days...not sure how you'll pass an MOT as emissions is all electronically done and recorded isn't it (as in the tester can't just overlook it...)?

You'll need to program out the post cat 02 sensors or you will get an error code I would think.

Can't help with the flat spot but not sure why'd be in that rev range anyway. Putting a lot of load / stress on the engine down in that range potentially, keep it 2k and above would be my advice and if it's fine from there up to the limiter I wouldn't worry about it, it's not a diesel :wink:
See if you are throwing any codes would be my only suggestion if it really bothers you but not unknown for some induction kits to cause some minor running issues on these.
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Mid pipe cats replaced - question

Post by Rockhopper » Thu Sep 23, 2021 3:43 pm

MOT man should visually check for the presence of factory fitted emission control devices. I suspect they are only going to get more strict on this one.

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Mid pipe cats replaced - question

Post by Verinder1984 » Tue Sep 28, 2021 11:28 am

Your right it’s a you’re bypass going in today in an hour.

Will let yall know how I feel about it.


AndyBeech wrote: Thu Sep 23, 2021 3:30 pm
Verinder1984 wrote: Thu Sep 23, 2021 2:55 pm
RedUn wrote: Thu Sep 23, 2021 12:46 pm Are you in the UK? Our cars only have 1 set of cats... So it won't pass an mot no...

Yes uk z4mr. Hummmm. I think I can fix emissions issue with mot not overly worried. Will it flare up any errors on dash? And with induction would you say it worth remapping.

I noticed with only induction it has flat spots between 1-2k rpm sometimes.
You sure he means the Cats and not the centre x pipe part / resonator? Seen that 'straight' piped before which will give a bit more sound and not cause any issues. Straight up cat delete seems risky these days...not sure how you'll pass an MOT as emissions is all electronically done and recorded isn't it (as in the tester can't just overlook it...)?

You'll need to program out the post cat 02 sensors or you will get an error code I would think.

Can't help with the flat spot but not sure why'd be in that rev range anyway. Putting a lot of load / stress on the engine down in that range potentially, keep it 2k and above would be my advice and if it's fine from there up to the limiter I wouldn't worry about it, it's not a diesel :wink:
See if you are throwing any codes would be my only suggestion if it really bothers you but not unknown for some induction kits to cause some minor running issues on these.

Verinder1984
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Mid pipe cats replaced - question

Post by Verinder1984 » Tue Sep 28, 2021 2:28 pm

Full waste of time. Got to the fabricators who said unless u change the cats or back box there’s nothing that can be done.

Bypassing the xpipe wouldn’t increase the sound as the car doesn’t have secondary cats.

Lollllllllllllll waste of 3h

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Mid pipe cats replaced - question

Post by Argenta » Tue Sep 28, 2021 3:07 pm

Yes, waste of time, just delete the backboxes if you need something LOUD...
Also the cats don't sip much power but do actual magic wonders to all the toxic stuff that we'd otherwise get.

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RedUn
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Mid pipe cats replaced - question

Post by RedUn » Tue Sep 28, 2021 8:14 pm

Verinder1984 wrote: Tue Sep 28, 2021 2:28 pm Full waste of time. Got to the fabricators who said unless u change the cats or back box there’s nothing that can be done.

Bypassing the xpipe wouldn’t increase the sound as the car doesn’t have secondary cats.

Lollllllllllllll waste of 3h
Hmm clearly doesn't have a clue.

The oem x pipe has a resonator, people have replaced with a non resonated x pipe such as the rogue version with the oem back boxes for a nice but not mental volume increase.

Secondary cats has nothing to do with it.

You could do both the cats and the x pipe but if imagine it would be quite raspy with the oem rear boxes.
Last edited by RedUn on Tue Sep 28, 2021 8:47 pm, edited 1 time in total.
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Mid pipe cats replaced - question

Post by Mr Tidy » Tue Sep 28, 2021 8:27 pm

So it looks like you'll need to go with aftermarket back-boxes if you want a bit more volume.

RPI and Eisman spring to mind, although a previous owner had Powerflow ones fitted to my car and I've been really pleased with them.

A back-box delete might be a bit too much volume, and if there is any chance you might do a track day you'd probably exceed noise limits!
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