[essex_lad]

I am just after a bit of advise from the guys on here that have done these mods. I want to remove only 1 set of cats from my N53 325i so my car still passes emissions tests but I'm not sure which ones to delete. I will be leaving the mid pipe silencers in to keep drone to a min.

Shall I get these for the header delete:

http://www.ebay.co.uk/itm/3319124853...%3AMEBIDX%3AIT

Or should I just cut out the mid cat and weld in a straight pipe?

[Taskmaster]

Originally Posted by essex_lad

I am just after a bit of advise from the guys on here that have done these mods. I want to remove only 1 set of cats from my N53 325i so my car still passes emissions tests but I'm not sure which ones to delete. I will be leaving the mid pipe silencers in to keep drone to a min.

Shall I get these for the header delete:

http://www.ebay.co.uk/itm/3319124853...%3AMEBIDX%3AIT

Or should I just cut out the mid cat and weld in a straight pipe?

If you're trying to pass the sniffer test, the headers will have you more than likely fail.

The secondaries (mid Pipe) will probably be the ones to remove.

[essex_lad]

Originally Posted by TheAxiom

If you're trying to pass the sniffer test, the headers will have you more than likely fail.

The secondaries (mid Pipe) will probably be the ones to remove.

OK well the secondary cats I can do easy enough myself so I'll do them then. Iv read about it can bring up errors though. Is this true?

Also will it change the sound much?

[Taskmaster]

Originally Posted by essex_lad

OK well the secondary cats I can do easy enough myself so I'll do them then. Iv read about it can bring up errors though. Is this true?

Also will it change the sound much?

No errors, and yes it will change the sound and probably add a little power too.

[essex_lad]

Originally Posted by TheAxiom

No errors, and yes it will change the sound and probably add a little power too.

Yer the power is the reason I want to get rid of them as one set is restricted enough never mind 2 lol.

Looks like I'll be making it tomorrow's project to remove the secondary cats then.

[Taskmaster]

Originally Posted by essex_lad

Yer the power is the reason I want to get rid of them as one set is restricted enough never mind 2 lol.

Looks like I'll be making it tomorrow's project to remove the secondary cats then.

a Super Sprint Mid should be allow you to reverse it if you need to.

[rick100]

if power is your concern then you ll get more out of deleting the primary cats, which probably means adding headers .

As for passing emissions , with the right tune and depending on how they do the emissions in your area you may pass. Anytime you are deleting cats there is always a chance you may not pass

Having said that, Im surprised not many peoplehere know the right people to make it pass

[Taskmaster]

Originally Posted by rick100

if power is your concern then you ll get more out of deleting the primary cats, which probably means adding headers .

As for passing emissions , with the right tune and depending on how they do the emissions in your area you may pass. Anytime you are deleting cats there is always a chance you may not pass

Having said that, Im surprised not many peoplehere know the right people to make it pass

He lives in the UK, which is why I didn't tell him to remove his primary Cats.

OP, if you buy the AFE headers, you could remove your secondaries, have more power and still pass emission tests.

[stewey]

Originally Posted by essex_lad

OK well the secondary cats I can do easy enough myself so I'll do them then. Iv read about it can bring up errors though. Is this true?

Also will it change the sound much?

Very little change in sound from removing the secondaries. Headers will produce more power and a bigger change in sound. I have no secondaries at the moment, mostly because it's a cheap and subtle way to pick up a few HP. In the future I might put them back and do headers instead, but hesitant because of the cost and potentially obnoxious sound.

[essex_lad]

Sound is a slight issue as Iv heard some of these engines with exhaust system and in my opinion they don't sound very nice, more along the sounds of rice lol. But maybe Iv just been spoilt with the beautiful sound of my v6 350z before this car, which in my opinion the v6 has the best sound from an engine.

Anyway going off topic, I'm not sure if I can get the afe pipes in the u.k and Iv read they are quite loud also. The super sprints are an easy way forward but I don't want the drone from loosing the silencers. Maybe I should stick with the safe option and just remove the secondary cats.

[Taskmaster]

Originally Posted by essex_lad

Sound is a slight issue as Iv heard some of these engines with exhaust system and in my opinion they don't sound very nice, more along the sounds of rice lol. But maybe Iv just been spoilt with the beautiful sound of my v6 350z before this car, which in my opinion the v6 has the best sound from an engine.

Anyway going off topic, I'm not sure if I can get the afe pipes in the u.k and Iv read they are quite loud also. The super sprints are an easy way forward but I don't want the drone from loosing the silencers. Maybe I should stick with the safe option and just remove the secondary cats.

You should have no issue getting the AFE headers in the UK, and the Super Sprint mid Pipes don't remove the resonator.

[essex_lad]

Originally Posted by TheAxiom

You should have no issue getting the AFE headers in the UK, and the Super Sprint mid Pipes don't remove the resonator.

Sadly I can't get the afe headers over here. Also the supersprint pipes would need importing from Europe. But after looking at the supersprint mid section at £1000 I think I'll leave it and just weld 2 pipes in lol.

[4foothill]

I've tried to get afe headers (also uk and n53) but I think there's an issue with fitting them on RHD.

Would be interested in what setup you go for in the end.

[Taskmaster]

Originally Posted by essex_lad

Sadly I can't get the afe headers over here. Also the supersprint pipes would need importing from Europe. But after looking at the supersprint mid section at £1000 I think I'll leave it and just weld 2 pipes in lol.

What are you talking about? You can absolutely import the AFE headers, and the Super Sprint mids are like $300usd.

[essex_lad]

Originally Posted by TheAxiom

What are you talking about? You can absolutely import the AFE headers, and the Super Sprint mids are like $300usd.

I could import them but by the time I pay import tax and then the delivery charges I may as well have a custom one made lol.

Iv looked at the supersprint cat delete pipes and they have a flange one end and an insert at the other which slots into the silencer section they sell. Both parts cost £1000. If I just get the cat delete pipes they are £300 and I would still need to cut my existing exhaust and have to try and clamp it on which defeats the object of having the pipes to change back to the cats in the future.

Plus £300 for just some bent pipes is a bit steep. My local exhaust shop can do the same thing for £200 and I won't even need to get my hands dirty.

[Taskmaster]

Originally Posted by essex_lad

I could import them but by the time I pay import tax and then the delivery charges I may as well have a custom one made lol.

Iv looked at the supersprint cat delete pipes and they have a flange one end and an insert at the other which slots into the silencer section they sell. Both parts cost £1000. If I just get the cat delete pipes they are £300 and I would still need to cut my existing exhaust and have to try and clamp it on which defeats the object of having the pipes to change back to the cats in the future.

Plus £300 for just some bent pipes is a bit steep. My local exhaust shop can do the same thing for £200 and I won't even need to get my hands dirty.

That's fair.

[Rival]

2nd cat del.

res del.

add y pipe, pick muffler and have a *real* muffler shop fab the rest.

it should be the cheapest and best way to go.