Removed my E46 330i cats recently

Kurt Adv

Member
AS above, just removed the ones under the car, they fitted a resonator box in place of both cats, not sure if I'm that happy, sound has changed, a bit more muted, not that growl the 330i is known for.....performance, feels a bit nippier, seems to rev a bit cleaner, and I think my fuel consumption has improved a bit....not sure if I want to remove the header cats, would be nice to get a complete replacement header that has been de-catted....
 

Zound

///Member
I have removed both sets of cats in my 2001 330i. The header cats I removed from the car and then had an exhaust company insert straight pipe as a replacement. The same method was used for the secondary cats. The car still has a deep growl and sounds absolutely awesome on cold start-up. Other than that, it's as smooth and refined as a BMW 6 cylinder should sound. Definitely better throttle response and it feels a tiny bit stronger.
 
I removed the bottom ones too, but replaced them with straight pipes.

@ Kurt - you removed both sets and replaced both sets with straight pipes
no resonators / boxes in place of these 4 cats ?

And you don't have any droning ?
 

Serg_ZA

Member
To all that have decatted their 330i's, what did you do in order to not have a check engine light appear?

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Just got a motor out of a 2000 but the motor caught fire not burnt super bad just melted plastics.

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So not sure anout the manifold

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stevehampshire39 said:
Just got a motor out of a 2000 but the motor caught fire not burnt super bad just melted plastics.

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So not sure anout the manifold

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Serg_ZA

Member
stevehampshire39 said:
Just got a motor out of a 2000 but the motor caught fire not burnt super bad just melted plastics.

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So not sure anout the manifold

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stevehampshire39 said:
Just got a motor out of a 2000 but the motor caught fire not burnt super bad just melted plastics.

Sent from my LGL43AL using Tapatalk


So not sure anout the manifold

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PM me

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Preshen14

Events Organiser
I have a 2004 330i and about a month ago I decided to do a full decat and stainless steal exhaust - it sounds amazing. I went the straight pipe route with replacing the cats and 2 performance boxes.
 

Kurt Adv

Member
Charlie Brown said:
I removed the bottom ones too, but replaced them with straight pipes.

@ Kurt - you removed both sets and replaced both sets with straight pipes
no resonators / boxes in place of these 4 cats ?

And you don't have any droning ?


They fitted a 2 in - 2 out box in place of the 2 cats, common entity between the 2 pipes now....was considering just straight pipes, no resonator box, but heard members say it was very noisy, will rethink this....dunno if I'm happy with the sound now, sounds to much like a 325.....
 

GPGrobler

///Member
Mine not a lot louder since removing the exhaust cats just a very nice additional low bass rumble at idle, removing the header cats next week and adding the resonators ... can't wait!!! :tiptoe:
 

Kurt Adv

Member
Ok, so today I had that horrible baffle removed, straight pipes fitted now where the underbody cats were, much better, and not too noisy, should have done this in the first place...but, when I checked out the workmanship on this baffle, not good, wrong diameter pipes used, 50mm instead of 45mm on the one side, and check out the pic, much smaller working diameter because of the crappy welding....
zorst...._5458377874.jpg
 
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