Gutting secondary cats?!

Needbmwpartzz · 07-23-2014, 04:31 PM

Deleted

E46driver · 07-23-2014, 04:36 PM

I haven't personally done it,but from other threads in this section learned that you get some more cabin noise as well although it is said to not be so intrusive. As for the sound, the resonator is what muffles a lot of the sound on the stock exhaust and removing that will give you a much more louder exhaust.

Asetoy2nr · 07-23-2014, 10:40 PM

I just had mine deleted due to one of them was rattling at idle. The exhaust tone is almost factory until you get to about 70 -75 mph. You then hear a little rumble, I'm talking about inside the vehicle, A/C on, and windows up.
On the outside of the vehicle, my friend tells me that my exhaust is a little raspier now. I have read some peoples posts, that say secondary cats and resonator delete, give them the sound they are looking for. Muffler delete is F@#king LOUD, I already made that mistake once. Lasted 24 hours, and I re-installed my muffler.

Taskmaster · 07-24-2014, 12:45 AM

Do it right and remove the whole section for best results.

Dylanize · 07-25-2014, 10:46 AM

Quote:

Originally Posted by TheAxiom

Do it right and remove the whole section for best results.

Think it's possible to put the gutted cats back on over straight pipes welded in for a stealth install?

I just want to pass visual inspection.

Taskmaster · 07-25-2014, 11:32 AM

Quote:

Originally Posted by Dylanize

Think it's possible to put the gutted cats back on over straight pipes welded in for a stealth install?

I just want to pass visual inspection.

Absolutely. The issue with the "gutted cat" vs a straight pipe is the flow characteristics of an empty chamber. My understanding is it can actually hurt power overall.

Rival · 07-25-2014, 12:05 PM

Quote:

Originally Posted by TheAxiom

Absolutely. The issue with the "gutted cat" vs a straight pipe is the flow characteristics of an empty chamber. My understanding is it can actually hurt power overall.

thats always been mine too. I wouldnt do it unless you can get the shell of the cat welded or secured to the stright pipe you would be replacing it with.

b-man · 07-25-2014, 06:20 PM

Quote:

Originally Posted by Dylanize

Quote:

Originally Posted by TheAxiom

Do it right and remove the whole section for best results.

Think it's possible to put the gutted cats back on over straight pipes welded in for a stealth install?

I just want to pass visual inspection.

I don't think you'll fail inspection if you remove secondary cats. 330 n52 doesn't have secondary cats at all, right? I thought I only primaries are required. At least here in maine.

I'm thinking about doing the same. Res and sec cat delete. I've done muffler delete before and droned too much. I just don't wanna have to put them back on cause it drones. I rather spend a little extra and have it right. Not $1000 though.

Does anyone know how loud res and sec cat delete is compared to pe?

Love The Drive · 07-26-2014, 10:37 PM

Quote:

Originally Posted by new_username

I don't think you'll fail inspection if you remove secondary cats. 330 n52 doesn't have secondary cats at all, right? I thought I only primaries are required. At least here in maine.

I'm thinking about doing the same. Res and sec cat delete. I've done muffler delete before and droned too much. I just don't wanna have to put them back on cause it drones. I rather spend a little extra and have it right. Not $1000 though.

Does anyone know how loud res and sec cat delete is compared to pe?

My guess is not as loud as the PE because the stock muffler is not designed to make a lot of noise. Very interested to hear what this set up sounds like though.

Route 16 · 07-27-2014, 12:47 AM

Quote:

Originally Posted by TheAxiom

Absolutely. The issue with the "gutted cat" vs a straight pipe is the flow characteristics of an empty chamber. My understanding is it can actually hurt power overall.

I made a cut after the 2ndary cats, took out the filling and placed a clamp over the cut. It's been like 5k miles on since then? No issues with my throttle/pressure loss (butt dyno) but I'll get an official dyno maybe this week.

To me, the exhaust has only one exit, it's not like it's making it's own tornado in the shell. Still looks stealthy.

Needbmwpartzz · 08-02-2014, 01:16 PM

Bump

EndOfAnEra · 08-02-2014, 01:35 PM

just buy some aFe race pipes, they sound great paired with my PE. I'd rather install new pipes than mess with the factory ones..

b-man · 08-02-2014, 01:54 PM

Some guys leave the secondary cats on because they have catless headers. I guess it helps with emissions. If you're planning on getting headers, you may want to leave them on

07-23-2014, 04:31 PM	#1
Needbmwpartzz Colonel 858 Rep 2,792 Posts Drives: 2009 bmw 328i x-drive Join Date: Feb 2014 Location: Kitchener/Waterloo iTrader: (0)	Deleted
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07-23-2014, 04:36 PM	#2
E46driver Captain 78 Rep 740 Posts Drives: 2009 E92 N51 328i Join Date: Jan 2012 Location: Rowland Heights iTrader: (4)	I haven't personally done it,but from other threads in this section learned that you get some more cabin noise as well although it is said to not be so intrusive. As for the sound, the resonator is what muffles a lot of the sound on the stock exhaust and removing that will give you a much more louder exhaust. __________________ 2009 Alpine White E92 N51 328i Automagic \| Premium & Sport Pkg. \| Coral Red/Black Dakota Leather Interior \| M-Spor \| BMW Performance Exhaust \| Active Autowerke Headers \| BBS CH-R \| CPS Front Lip \| Performance Front Grills \| 888Concepts Custom Headlights (GONE) 2011 Alpine White E90 N55 335i Automagic
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07-23-2014, 10:40 PM	#3
Asetoy2nr Dude, where's my car? 15 Rep 51 Posts Drives: 2016 328i Join Date: Feb 2013 Location: Davie, Florida iTrader: (0)	I just had mine deleted due to one of them was rattling at idle. The exhaust tone is almost factory until you get to about 70 -75 mph. You then hear a little rumble, I'm talking about inside the vehicle, A/C on, and windows up. On the outside of the vehicle, my friend tells me that my exhaust is a little raspier now. I have read some peoples posts, that say secondary cats and resonator delete, give them the sound they are looking for. Muffler delete is F@#king LOUD, I already made that mistake once. Lasted 24 hours, and I re-installed my muffler.
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07-24-2014, 12:45 AM	#4
Taskmaster Banned 2476 Rep 9,004 Posts Drives: M235i 6MT / E92 328 Msport 6MT Join Date: Nov 2013 Location: Florida iTrader: (6)	Do it right and remove the whole section for best results.
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08-02-2014, 01:16 PM	#11
Needbmwpartzz Colonel 858 Rep 2,792 Posts Drives: 2009 bmw 328i x-drive Join Date: Feb 2014 Location: Kitchener/Waterloo iTrader: (0)	Bump
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08-02-2014, 01:35 PM	#12
EndOfAnEra Lieutenant Colonel 523 Rep 1,707 Posts Drives: F16 X6 Msport Join Date: May 2012 Location: Largo, FL iTrader: (13)	just buy some aFe race pipes, they sound great paired with my PE. I'd rather install new pipes than mess with the factory ones.. __________________ flickr
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08-02-2014, 01:54 PM	#13
b-man Major 608 Rep 1,090 Posts Drives: 328xi Join Date: Jan 2013 Location: maine iTrader: (2)	Some guys leave the secondary cats on because they have catless headers. I guess it helps with emissions. If you're planning on getting headers, you may want to leave them on
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