Secondary Cat Delete Question

Lou2 · 07-19-2011, 11:26 AM

I have the BMW performance exhaust currently installed and am thinking about deleting the secondary cats. Will this cause me to fail emissions testing when i need an inspection? Also, will it cause any lights to come up on my dash?

dirte90 · 07-19-2011, 11:42 AM

No lights on the dash and it should pass the sniffer test... even in CA. I suppose if you had a REALLY intense inspector the might catch it on the visual.

I will never admit to deleting secondary cats in a public forum... but I do know for a fact that the above statement is true.

Lou2 · 07-19-2011, 03:30 PM

thanks for the response. and the advice!

Anyone without secondary cats have any issues?

MrRager · 07-19-2011, 09:04 PM

these cars run clean enough till you shouldnt experience any problems.

craigmc163 · 07-31-2011, 08:28 AM

i have taken mine out with no issues, however i am also wondering about the inspection? I am thinking about putting mine back in anyway b/c im not sure there is any advantage to not having them and feel like bmw is smarter than i so im sure they are there for a reason?(backpresure)

DetailAddict · 08-01-2011, 05:45 PM

how are you going to delete the secondary cats? If you are just cutting them off and welding some pipes in place, then I can see the problem. But if you build out a new piece from the flanges, then when the time comes, just put the stocker back in...

MaximusJ · 08-01-2011, 06:51 PM

Quote:

Originally Posted by craigmc163

bmw is smarter than i so im sure they are there for a reason?(backpresure)

Cats arent there because BMW decided so; but because they are forced by law to do so. Thanks to EPA.

The muffler creates the backpressure, but the cats are just filtering gases. You got two sets of them; there's one too many. You should consider deleting the resonator while you're at it. Wouldnt cost a lot more.

craigmc163 · 08-03-2011, 03:38 PM

I have the fake eisenmann exhaust on it now! GT haus! It is section 2 and 3. Section 3 is the rear muffler section! Section 2 are the mid pipes that bolt to the flange. Was just thinking I don't need section 2? Seems to have no purpose except to make it louder and delete the second set of cats?

MaximusJ · 08-03-2011, 04:10 PM

Quote:

Originally Posted by craigmc163

I have the fake eisenmann exhaust on it now! GT haus! It is section 2 and 3. Section 3 is the rear muffler section! Section 2 are the mid pipes that bolt to the flange. Was just thinking I don't need section 2? Seems to have no purpose except to make it louder and delete the second set of cats?

The resonator delete makes it louder.
The cat delete makes it flow better.

DetailAddict · 08-03-2011, 05:15 PM

so folks running secondary cat and resonator delete are not getting drones?

capo1m · 08-03-2011, 07:30 PM

i have ikon exhaust intake and resonator delete as well as secondary cat delete u def feel power and will be fine with emissions its a little loud at low rpms in the cabinent and doesnt idle much louder but its awesome when ur feeling spirited

Lou2 · 10-25-2011, 10:28 AM

So if i have the BMW performance exhaust do i still have a resonator after the secondary cats? i thought this system deleted that.

engotski · 10-26-2011, 04:14 PM

Quote:

Originally Posted by Lou2

So if i have the BMW performance exhaust do i still have a resonator after the secondary cats? i thought this system deleted that.

Resonator gone but secondary cats are present

1QuikWS6 · 10-27-2011, 02:01 AM

Actually, there hasn't been a 'sniff' test on cars for Emissions testing for years now...

On all newer cars they simply plug the test maching to OBD port - it checks systems thru this port for full functionality.

If there are any errors found, or the visible dash warning icon showing for emissions issues - the car will fail.

The actual machine hookup is only part of passing the emissions test. If your garage is strict - there is also a visual part of the test.

Where the technician actually looks to see that ALL emissions related components are present under the hood and UNDER THE CAR - in that case, you would fail due to missing secondary cat's.

As previously stated, BMW doesn't add them just for shits and giggles - they are there because they are mandated.

With that being said, you can always find a garage that doesn't bother with the visual part of the test, and since there are no sensors related to the secondary cat's - you will also pass the machine part of the test.

Whateva · 09-16-2014, 12:10 AM

Has anyone recently cut the secondary cats and passed smog?

Route 16 · 09-16-2014, 01:21 AM

Quote:

Originally Posted by Whateva

Has anyone recently cut the secondary cats and passed smog?

I did but the midpipe was the eisenmann midpipe so no welds/alteration to the pipe was noted. As if it was meant to be like that.

Whateva · 09-16-2014, 01:31 AM

Quote:

Originally Posted by Route 16

Quote:

Originally Posted by Whateva

Has anyone recently cut the secondary cats and passed smog?

I did but the midpipe was the eisenmann midpipe so no welds/alteration to the pipe was noted. As if it was meant to be like that.

Did they perform a visual inspection?

07-19-2011, 11:26 AM	#1
Lou2 Private 8 Rep 68 Posts Drives: 2007 328xi 6MT Join Date: Jan 2011 Location: NY iTrader: (0)	Secondary Cat Delete Question I have the BMW performance exhaust currently installed and am thinking about deleting the secondary cats. Will this cause me to fail emissions testing when i need an inspection? Also, will it cause any lights to come up on my dash?
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07-19-2011, 11:42 AM	#2
dirte90 Second Lieutenant 40 Rep 259 Posts Drives: E90 328i Join Date: Sep 2010 Location: SoCal iTrader: (2)	No lights on the dash and it should pass the sniffer test... even in CA. I suppose if you had a REALLY intense inspector the might catch it on the visual. I will never admit to deleting secondary cats in a public forum... but I do know for a fact that the above statement is true. __________________
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07-19-2011, 03:30 PM	#3
Lou2 Private 8 Rep 68 Posts Drives: 2007 328xi 6MT Join Date: Jan 2011 Location: NY iTrader: (0)	thanks for the response. and the advice! Anyone without secondary cats have any issues?
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07-19-2011, 09:04 PM	#4
MrRager First Lieutenant 19 Rep 381 Posts Drives: 335i Join Date: Jul 2011 Location: 73134 iTrader: (0)	these cars run clean enough till you shouldnt experience any problems. __________________ 2008 335i 6MT
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07-31-2011, 08:28 AM	#5
craigmc163 fulltilte90 11 Rep 199 Posts Drives: 06 330xi Join Date: Dec 2010 Location: Nashville tn iTrader: (7)	i have taken mine out with no issues, however i am also wondering about the inspection? I am thinking about putting mine back in anyway b/c im not sure there is any advantage to not having them and feel like bmw is smarter than i so im sure they are there for a reason?(backpresure)
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08-01-2011, 05:45 PM	#6
DetailAddict Captain 41 Rep 976 Posts Drives: 2008 BMW 328i Join Date: Jan 2008 Location: Santa Clara, CA iTrader: (10)	how are you going to delete the secondary cats? If you are just cutting them off and welding some pipes in place, then I can see the problem. But if you build out a new piece from the flanges, then when the time comes, just put the stocker back in...
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08-03-2011, 03:38 PM	#8
craigmc163 fulltilte90 11 Rep 199 Posts Drives: 06 330xi Join Date: Dec 2010 Location: Nashville tn iTrader: (7)	I have the fake eisenmann exhaust on it now! GT haus! It is section 2 and 3. Section 3 is the rear muffler section! Section 2 are the mid pipes that bolt to the flange. Was just thinking I don't need section 2? Seems to have no purpose except to make it louder and delete the second set of cats? __________________ Bilstein Sports, H&R Lowering Spring, Blacklines, Custom Alcantara Shift boot and Brake Boot, BMW performance shift knob, BMS Power Box, DAEOS Harness, BMS Angel eye upgrades, Injen Performance intake, GT haus Full exhaust system.
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08-03-2011, 05:15 PM	#10
DetailAddict Captain 41 Rep 976 Posts Drives: 2008 BMW 328i Join Date: Jan 2008 Location: Santa Clara, CA iTrader: (10)	so folks running secondary cat and resonator delete are not getting drones?
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08-03-2011, 07:30 PM	#11
capo1m Colonel 89 Rep 2,030 Posts Drives: 1M, M4 Join Date: Nov 2009 Location: Middletown,Ny iTrader: (17)	i have ikon exhaust intake and resonator delete as well as secondary cat delete u def feel power and will be fine with emissions its a little loud at low rpms in the cabinent and doesnt idle much louder but its awesome when ur feeling spirited __________________ AW E82 1M MW F82 M4
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10-25-2011, 10:28 AM	#12
Lou2 Private 8 Rep 68 Posts Drives: 2007 328xi 6MT Join Date: Jan 2011 Location: NY iTrader: (0)	So if i have the BMW performance exhaust do i still have a resonator after the secondary cats? i thought this system deleted that.
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10-27-2011, 02:01 AM	#14
1QuikWS6 No 55mph 1621 Rep 8,476 Posts Drives: F32 435ix MSport Join Date: Jul 2009 Location: Blitzburgh, PA iTrader: (113) Garage List 2022 BMW M440ix Vert [0.00] 2015 BMW 435ix MSport [0.00] 2000 Pontiac Trans Am [0.00]	Actually, there hasn't been a 'sniff' test on cars for Emissions testing for years now... On all newer cars they simply plug the test maching to OBD port - it checks systems thru this port for full functionality. If there are any errors found, or the visible dash warning icon showing for emissions issues - the car will fail. The actual machine hookup is only part of passing the emissions test. If your garage is strict - there is also a visual part of the test. Where the technician actually looks to see that ALL emissions related components are present under the hood and UNDER THE CAR - in that case, you would fail due to missing secondary cat's. As previously stated, BMW doesn't add them just for shits and giggles - they are there because they are mandated. With that being said, you can always find a garage that doesn't bother with the visual part of the test, and since there are no sensors related to the secondary cat's - you will also pass the machine part of the test. __________________ F32 435ix//MGM//M Sport-Prem-Tech-Driver Assist-Lighting-Cold Weather-Dyn Handling Pkgs//M4 Black Lthr Int w/M4 Alum Blade Trim//HK w/Bavsound Stg3//763M//M4 Euro LCI Tails//M4 Mirrors w/CF Covers//AWCarbon CF F/R Spoilers-Side Splitters-Diffuser 6WB/ID6 HU+HUD/IND M4 Alcantara Armrest//PURE S2 Turbo//AA FMIC+DP//ER CP+TIC//3.5bar TMAP/TS DV//AWE Tuning Exh w/Blk Tips//Turner MS CF Intake//BM3 Cary Jordan Tune//MPerf Diff//PrecRW Ignition Kit
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09-16-2014, 12:10 AM	#15
Whateva Banned 27 Rep 228 Posts Drives: 335i Join Date: Apr 2014 Location: La La Land iTrader: (0) Garage List 2008 335i [10.00]	Has anyone recently cut the secondary cats and passed smog?
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