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.

SSRE · 03-24-2012, 04:36 PM

How much HP is gained from secondary cat removal?

jordanE92 · 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 Drives: E92M3 Join Date: Jun 2011 Location: Hong Kong Posts: 126 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?
	Tweet

03-13-2012, 01:11 AM	#2
FVM3 Brigadier General Drives: 2011 E93 M3 Join Date: Sep 2010 Location: Los Angeles Posts: 4,841 iTrader: (2)	as soon as you have the stock muffler, no drone but sounds really raspy __________________ 2011 E93 DCT

03-13-2012, 02:48 AM	#4
FVM3 Brigadier General Drives: 2011 E93 M3 Join Date: Sep 2010 Location: Los Angeles Posts: 4,841 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. __________________ 2011 E93 DCT

03-13-2012, 03:57 AM	#5
saeedg48 Brigadier General Drives: 2008 6MT E90 M3 & 2012 CLS63 P Join Date: Nov 2008 Location: Unknown Posts: 3,354 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. __________________ _______________

03-13-2012, 12:30 PM	#11
flipm3 E46 + E90 Drives: E46 M3 + E90 M3 Join Date: Jul 2008 Location: Illinois Posts: 2,486 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. __________________ 2002 E46 M3 6MT \| Jet Black . Black Nappa \| My Build Thread 2009 E90 M3 DCT \| Melbourne Red . Speed Cloth

03-13-2012, 02:23 AM	#3
raywong Private First Class Drives: E92M3 Join Date: Jun 2011 Location: Hong Kong Posts: 126 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

03-13-2012, 05:49 AM	#7
raywong Private First Class Drives: E92M3 Join Date: Jun 2011 Location: Hong Kong Posts: 126 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.

03-13-2012, 12:37 PM	#12
1MOREMOD Major General Drives: at a moderate pace Join Date: Mar 2009 Location: garage Posts: 6,530 iTrader: (3)	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 race control arms\|GC bushings & bearings\|BW eng. & tran. mounts\|subframe kit\|BW race shifter\|BW Jaffster knob\|Euro header\|Eisenmann sport\|K&N c.a.i.\|Seibon CF hood\|CSL bumper\|CSL brakes\|RS19s\|SS lines\|half cage\|Recaro profi\|Profi 2 harness\|race pulleys\|BMWpedals\|Apex studs\|1995 Ford Probe gt chump car\|

03-13-2012, 01:01 PM	#13
DemonEye Private Drives: 2012 M3 Coupe, 2005 M3 Coupe Join Date: Jul 2011 Location: Charlotte, NC Posts: 80 iTrader: (0) Garage List 2012 M3 Coupe [0.00] 2005 M3 Coupe [3.00]	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

03-22-2012, 01:31 PM	#14
abramelkyzedeck Private First Class Drives: bmw m3 Join Date: Sep 2011 Location: san francisco Posts: 110 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

03-23-2012, 05:46 AM	#17
blackbeast535 Private First Class Drives: 2008 M3 6MT Jerez Black Join Date: Aug 2011 Location: MD Posts: 142 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

03-24-2012, 04:36 PM	#18
SSRE Second Lieutenant Drives: M3 Join Date: Mar 2012 Location: North East Posts: 250 iTrader: (1)	How much HP is gained from secondary cat removal?

03-27-2012, 07:24 AM	#20
e92Mjunky Second Lieutenant Drives: New wife Alpine CF E92 M3 Join Date: Mar 2011 Location: Austin, TX Posts: 272 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 __________________ 08' DCT CF Roof, nothing to fancy custom magnaflow exhaust amd drop in filter

03-27-2012, 01:23 PM	#22
e92Mjunky Second Lieutenant Drives: New wife Alpine CF E92 M3 Join Date: Mar 2011 Location: Austin, TX Posts: 272 iTrader: (0)	yeah i noticed that on mine, looked like the secondarys were a smaller diameter, but you are probably correct... __________________ 08' DCT CF Roof, nothing to fancy custom magnaflow exhaust amd drop in filter

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search