secondary cat delete

raywong · 03-13-2012, 12:59 AM

has anyone removed the secondary cats? I wanted to do it but the muffler guy is warning me about the 2000rpm drone. I really don't want any drone just want higher pitch. Any advice please?

FVM3 · 03-13-2012, 01:11 AM

as soon as you have the stock muffler, no drone but sounds really raspy

raywong · 03-13-2012, 02:23 AM

Hey man what's up?
I just installed innotech valvetronic exhaust on my 360, so much drone I get a headache all the time. This is why I started using my M3 more now. Anything else I need to know about cats removal?
Thanks

FVM3 · 03-13-2012, 02:48 AM

it will say incresed emission but theres some way to get rid of that. If you get the innotech , you may get drone after deleting resonator but not cats.

saeedg48 · 03-13-2012, 03:57 AM

i had a catless xpipe. i wouldn't recommend it. they're no power gains. i'd consider a primary catdelete. it sounds much better. nice growl, and with my stock mufflers i didn't get any drone, despite what some claim on the forums. so do a primary catdelete (turner test pipe ~$300). once you CEL turns on ignore it, tune it, or purchase the akro cel delete.

more power, more noise.

FVM3 · 03-13-2012, 04:07 AM

Quote:

Originally Posted by saeedg48

i had a catless xpipe. i wouldn't recommend it. they're no power gains. i'd consider a primary catdelete. it sounds much better. nice growl, and with my stock mufflers i didn't get any drone, despite what some claim on the forums. so do a primary catdelete (turner test pipe ~$300). once you CEL turns on ignore it, tune it, or purchase the akro cel delete.

more power, more noise.

x pipe should gain some hp but not much

raywong · 03-13-2012, 05:49 AM

I heard the primary cats are 400cell and secondary are 200cell What if I replace the primary cats with straight pipe and move the sensors to the secondary cats. This way I get free flowing system without cel.

M3SQRD · 03-13-2012, 07:02 AM

Quote:

Originally Posted by raywong

I heard the primary cats are 400cell and secondary are 200cell What if I replace the primary cats with straight pipe and move the sensors to the secondary cats. This way I get free flowing system without cel.

You'll still get a CEL because the O2 sensors are located before and after the primary cats. Relocating the primary cats is basically the same as removing them - the rear O2 sensors will have the same readings/measurements as the front O2 sensors so the DME will detect a cat inefficiency issue.

Templar · 03-13-2012, 08:54 AM

Quote:

Originally Posted by saeedg48

i had a catless xpipe. i wouldn't recommend it. they're no power gains. i'd consider a primary catdelete. it sounds much better. nice growl, and with my stock mufflers i didn't get any drone, despite what some claim on the forums. so do a primary catdelete (turner test pipe ~$300). once you CEL turns on ignore it, tune it, or purchase the akro cel delete.

more power, more noise.

Hmm, I'm pretty sure a catless setup is the (if not one of the) best and most cost effective ways to get more power...

M3PO · 03-13-2012, 12:16 PM

Quote:

Originally Posted by raywong

I heard the primary cats are 400cell and secondary are 200cell What if I replace the primary cats with straight pipe and move the sensors to the secondary cats. This way I get free flowing system without cel.

You may still get a CEL from time to time if you do this. It would be similar to the Fabspeed x-pipe. People occasionally get a CEL but it will go away.

I have an OEM x-pipe with a secondary cat delete only and it isn't much different than stock honestly. Removing the secondary cat is only good for a few horsepower also since the catalyst pitch is so large.

flipm3 · 03-13-2012, 12:30 PM

Depending on how much you want to spend, I'd do the following:

Primary Cat Delete (Turner Test Pipes or any other cat'd mid pipe)
Evolve Automotive Stage 2 Tune

The Evolve tune will not only add power, but it will remove the CEL while keeping your post-cat O2 sensors in ready state for off-road use.

1MOREMOD · 03-13-2012, 12:37 PM

lot less to gain from secondary cat delete than the primaries and will add drone like going fully catless. as above i am stage 2 with evolve and love it.

DemonEye · 03-13-2012, 01:01 PM

I had my OEM xpipe gutted, both primary and secondary cats are gone. Sound is pretty "mean" when wide open, sounds stock when light on the throttle. Not hearing this drone that people are talking about. Still have stock resonators and stock exhaust in place though. Smell is pretty bad. I have the AA tune so no CEL for me.

abramelkyzedeck · 03-22-2012, 01:31 PM

i just removed my primary cats and as usual the cel was on. I was wondering if the cel will turn off if i installed back the primary cats

Rekrul · 03-22-2012, 02:05 PM

Quote:

Originally Posted by abramelkyzedeck

i just removed my primary cats and as usual the cel was on. I was wondering if the cel will turn off if i installed back the primary cats

Yes it would. Though you may need to clear the code once you reinstall your primary.

I have the DINAN catless x pipe.. and it sounds fuckin amazing. No Drone. But I have the Akra slip on too.

aus · 03-22-2012, 02:08 PM

Quote:

Originally Posted by raywong

I heard the primary cats are 400cell and secondary are 200cell What if I replace the primary cats with straight pipe and move the sensors to the secondary cats. This way I get free flowing system without cel.

It's not easy to extend the O2 sensors. You need to have cables that are almost exactly the same density as the stock ones. It has to do with conductance of the cable in combination with the actual O2 sensor.
I would love to get rid of the primary cats, and have a 200 or 300cpi cat in the secondary cat location and move the O2 sensor back to after the cats in the secondary position. No tune necessary, no check engine light and less smell than the Akra X-pipe.

.

blackbeast535 · 03-23-2012, 05:46 AM

I have removed the secondaries and running Dinan rear mufflers no drone here. Sounds exotic above 3k rpm. Definitely a head turner. Do a search and find my review.

Verify · 03-24-2012, 04:36 PM

How much HP is gained from secondary cat removal?

In Extremis · 03-24-2012, 06:06 PM

Quote:

Originally Posted by Rekrul

Yes it would. Though you may need to clear the code once you reinstall your primary.

I have the DINAN catless x pipe.. and it sounds fuckin amazing. No Drone. But I have the Akra slip on too.

Nice combo^^^

I'm going to start running my catless xpipe this week with the stock axle back. It's a non-resonated gintani, should be interesting. I wouldn't bother with the secondary cats unless you do the primaries too. Keeping the stock xpipe is up to you.

e92Mjunky · 03-27-2012, 07:24 AM

wonder if it would be worth removing the secondary cats and welding them in where the primary's are...that way you still have cats, just more flowing and you get rid of the more restrictive primarys

1MOREMOD · 03-27-2012, 08:50 AM

Quote:

Originally Posted by e92Mjunky

wonder if it would be worth removing the secondary cats and welding them in where the primary's are...that way you still have cats, just more flowing and you get rid of the more restrictive primarys

the original cats are also smashed flat as is the piping in that area. going to hfc also removes these areas of restriction in the flow.

e92Mjunky · 03-27-2012, 01:23 PM

yeah i noticed that on mine, looked like the secondarys were a smaller diameter, but you are probably correct...

03-13-2012, 12:59 AM	#1
raywong Private First Class 42 Rep 132 Posts Drives: E92M3 Join Date: Jun 2011 Location: Hong Kong iTrader: (0)	secondary cat delete has anyone removed the secondary cats? I wanted to do it but the muffler guy is warning me about the 2000rpm drone. I really don't want any drone just want higher pitch. Any advice please?
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03-13-2012, 01:11 AM	#2
FVM3 Major General 270 Rep 5,751 Posts Drives: e92 m3, f30 328i Join Date: Sep 2010 Location: Los Angeles iTrader: (2)	as soon as you have the stock muffler, no drone but sounds really raspy
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03-13-2012, 02:23 AM	#3
raywong Private First Class 42 Rep 132 Posts Drives: E92M3 Join Date: Jun 2011 Location: Hong Kong iTrader: (0)	Hey man what's up? I just installed innotech valvetronic exhaust on my 360, so much drone I get a headache all the time. This is why I started using my M3 more now. Anything else I need to know about cats removal? Thanks
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03-13-2012, 02:48 AM	#4
FVM3 Major General 270 Rep 5,751 Posts Drives: e92 m3, f30 328i Join Date: Sep 2010 Location: Los Angeles iTrader: (2)	it will say incresed emission but theres some way to get rid of that. If you get the innotech , you may get drone after deleting resonator but not cats.
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03-13-2012, 03:57 AM	#5
saeedg48 Brigadier General 342 Rep 3,574 Posts Drives: Porsche 991.1 GT3 Join Date: Nov 2008 Location: Newport Beach, CA iTrader: (1)	i had a catless xpipe. i wouldn't recommend it. they're no power gains. i'd consider a primary catdelete. it sounds much better. nice growl, and with my stock mufflers i didn't get any drone, despite what some claim on the forums. so do a primary catdelete (turner test pipe ~$300). once you CEL turns on ignore it, tune it, or purchase the akro cel delete. more power, more noise. __________________ 2015 Porsche 991.1 GT3 2015 F80 M3 -- Individual; Space Grey
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03-13-2012, 05:49 AM	#7
raywong Private First Class 42 Rep 132 Posts Drives: E92M3 Join Date: Jun 2011 Location: Hong Kong iTrader: (0)	I heard the primary cats are 400cell and secondary are 200cell What if I replace the primary cats with straight pipe and move the sensors to the secondary cats. This way I get free flowing system without cel.
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03-13-2012, 12:30 PM	#11
flipm3 E46 + E90 + F80 192 Rep 2,894 Posts Drives: E46 + E90 + F80 Join Date: Jul 2008 Location: Illinois iTrader: (1) Garage List 2009 BMW M3 [0.00] 2002 BMW M3 [0.00]	Depending on how much you want to spend, I'd do the following: Primary Cat Delete (Turner Test Pipes or any other cat'd mid pipe) Evolve Automotive Stage 2 Tune The Evolve tune will not only add power, but it will remove the CEL while keeping your post-cat O2 sensors in ready state for off-road use. __________________ F80 M3 DCT\|Alpine White . Black Leather \| My Build Thread E90 M3 DCT\|Melbourne Red . Speed Cloth \| My Build Thread E46 M3 6MT\|Jet Black . Black Nappa Leather \| My Build Thread
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03-13-2012, 12:37 PM	#12
1MOREMOD - 11817 Rep 23,187 Posts Drives: Race car-> Join Date: Mar 2009 Location: check your mirrors iTrader: (5)	lot less to gain from secondary cat delete than the primaries and will add drone like going fully catless. as above i am stage 2 with evolve and love it. __________________ 02 Tiag e46 M3\|6MT\|GC plates\|MCS c.o.\|GC bars\|GC race control arms\|GC bushings\|BW eng. & tran. mounts\|subframe kit\|BW race shifter\|BW Jaffster\|Euro header\|BW exhaust\|K&N c.a.i.\|Epic race tune\|Rouge pulleys\|Seibon CF hood\|CSL bumper\|apr gt 250 & splitter\|ST-40\|XR-2\|SS lines\|half cage\|Recaro profi\|Profi 2 harness\|BMWpedals\|BW studs\|
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03-13-2012, 01:01 PM	#13
DemonEye Private First Class 6 Rep 107 Posts Drives: 2012 M3 Coupe ESS VT2-625 Join Date: Jul 2011 Location: Charlotte, NC iTrader: (0) Garage List 2010 135i Coupe [0.00] 2012 M3 Coupe [0.00]	I had my OEM xpipe gutted, both primary and secondary cats are gone. Sound is pretty "mean" when wide open, sounds stock when light on the throttle. Not hearing this drone that people are talking about. Still have stock resonators and stock exhaust in place though. Smell is pretty bad. I have the AA tune so no CEL for me. __________________ www.carolinaeuros.com Carolina Euros Facebook Page
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03-22-2012, 01:31 PM	#14
abramelkyzedeck Private First Class 32 Rep 130 Posts Drives: 15' 435i M-sport Join Date: Sep 2011 Location: Singapore iTrader: (0)	i just removed my primary cats and as usual the cel was on. I was wondering if the cel will turn off if i installed back the primary cats
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03-23-2012, 05:46 AM	#17
blackbeast535 Private First Class 23 Rep 145 Posts Drives: 2008 M3 6MT Jerez Black Join Date: Aug 2011 Location: MD iTrader: (0)	I have removed the secondaries and running Dinan rear mufflers no drone here. Sounds exotic above 3k rpm. Definitely a head turner. Do a search and find my review. __________________ E90 M3 Jerez Black/Bamboo Beige 6MT - BMW CCA Dinan Rear Exhaust, Secondary Cat Delete, Dinan High Flow Carbon Fiber Intake, IND Painted Reflectors, BMW Edition Grills
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03-24-2012, 04:36 PM	#18
Verify Captain 23 Rep 638 Posts Drives: M3 Join Date: Mar 2012 Location: MD-NY iTrader: (1)	How much HP is gained from secondary cat removal?
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03-27-2012, 07:24 AM	#20
e92Mjunky First Lieutenant 111 Rep 395 Posts Drives: E46 M3 S65 swap Join Date: Mar 2011 Location: Austin, TX iTrader: (0)	wonder if it would be worth removing the secondary cats and welding them in where the primary's are...that way you still have cats, just more flowing and you get rid of the more restrictive primarys __________________ E46 M3 S65 swap
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03-27-2012, 01:23 PM	#22
e92Mjunky First Lieutenant 111 Rep 395 Posts Drives: E46 M3 S65 swap Join Date: Mar 2011 Location: Austin, TX iTrader: (0)	yeah i noticed that on mine, looked like the secondarys were a smaller diameter, but you are probably correct... __________________ E46 M3 S65 swap
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