Anyone's N52 have secondary cats? - BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i)

NA_Villhauser · 06-26-2011, 01:56 PM

My understanding has been that the N51 has an extra pair of cats in addtion to the cats in the exhaust manifolds. It also is supposed to have lower compression and the two stage intake manifold to make up for any power loss from the extra cats and lowered compression.

The different exhausts can be seen in the attached images from real oem. I noticed my 128i has the secondary cats shown for the N51 but does not have the two stage intake. According to my VIN I'm supposed to have an N52 and the block is stamped N52B30 right next to the serial number.

I'm curious to know who else has these extra cats on an N52.

Taymaishu · 06-26-2011, 04:53 PM

'09 N52 and no secondary cats.

AW128i · 06-27-2011, 12:13 PM

My car is N51-equipped and it has the secondary cats under the car. It also has the 3-stage intake manifold, secondary air injection, and an ozone-fighting radiator coating, all of which help it achieve the SULEV II EPA rating. I can't verify the reduced compression ratio, but it's heavily rumored that the N51 does have a lower compression ratio than the comparable N52. I can tell you from personal experience piloting both engines that the N51 has a slightly but noticeably different power curve than a comparable N52.

NA_Villhauser · 06-27-2011, 03:53 PM

I'm bummed that my car has the secondary cats but no 3-stage intake. My engine is clearly marked as an N52B30AE. Why would it have the extra cats?

rvsixdriver · 08-18-2011, 05:54 AM

I also have a 2011 6MT sport pack

My exhaust system looks like the lower picture you posted. I saw in an earlier post that the n52 has ULEV and n51 has sulev II on the emissions sticker. Mine says ULEV II. I'm not too sure where the engine serial number is on my car, but I would guess I have the same setup you have.

One question would be is it legal to eliminate one stage of a two stage system? Which one would you eliminate?

How do I tell if I have a three stage intake?

AW128i · 08-18-2011, 07:12 AM

According to the EPA's website, there are actually three versions of the 128i engine in the U.S.: Bin 5 N52 (Federal), ULEV II N52 (CARB), SULEV II N51 (CARB). This spans the entire E82 U.S. production (i.e., 2008-present). I'm guessing the CARB version of the N52 has the secondary cats and the Federal version does not.

rvsixdriver · 08-18-2011, 10:45 PM

Quote:

Originally Posted by AW128i

According to the EPA's website, there are actually three versions of the 128i engine in the U.S.: Bin 5 N52 (Federal), ULEV II N52 (CARB), SULEV II N51 (CARB). This spans the entire E82 U.S. production (i.e., 2008-present). I'm guessing the CARB version of the N52 has the secondary cats and the Federal version does not.

I have now verified that I have an N52 by punching my VIN into Real Oem. I still am interested in learning if I have a three stage intake.

AW128i · 08-19-2011, 09:27 AM

Quote:

Originally Posted by rvsixdriver

I have now verified that I have an N52 by punching my VIN into Real Oem. I still am interested in learning if I have a three stage intake.

Unless BMW made a change for the '11 model year, the U.S. N52-equipped 1-series does not have the 3-stage intake manifold.

Soccs · 08-19-2011, 09:53 AM

Hello,

I am sorry for this noob question. but what the significant diference between each other?

thank you

Greenkirby21 · 08-19-2011, 11:59 AM

Quote:

Originally Posted by Soccs

Hello,

I am sorry for this noob question. but what the significant diference between each other?

thank you

cats or 3 stage manifold?

Soccs · 08-21-2011, 07:16 AM

Hello Greenkirby,

the 3 stage manifold

thanks

wolfe · 08-21-2011, 01:24 PM

'11 N52, and my exhaust looks like the lower picture too.

Dackelone · 08-21-2011, 05:42 PM

It might be that the cars with the secondary cats are SULE cars (ie CA specs). ?

The three stage intake manifold is also called: DISA. IF you google that you will find lots of info about how it works. BMW has used that DISA intake manifold on lots of other models as well. Some of the German tuners can reprogram the two stage intake (DISA too) to make a big Hp increase. Normally they can get around 275 PS with just a chip tune on a N52.

AW128i · 08-22-2011, 09:30 AM

Quote:

Originally Posted by Dackelone

It might be that the cars with the secondary cats are SULE cars (ie CA specs). ?

The three stage intake manifold is also called: DISA. IF you google that you will find lots of info about how it works. BMW has used that DISA intake manifold on lots of other models as well. Some of the German tuners can reprogram the two stage intake (DISA too) to make a big Hp increase. Normally they can get around 275 PS with just a chip tune on a N52.

The N52 with the secondary cats is ULEV II-compliant. The N51 has lower compression, 3-stage intake manifold, secondary cats, secondary air injection, and ozone-reducing radiator and is SULEV II-compliant. The N52 without the secondary cats is Bin 5-compliant (i.e., LEV II) and is only available outside CARB-compliant states, but I'm not sure if maybe some of those states offer the ULEV II N52 by choice/default, or how exactly it works.

Dackelone · 08-22-2011, 10:23 AM

Quote:

Originally Posted by AW128i

The N52 with the secondary cats is ULEV II-compliant. The N51 has lower compression, 3-stage intake manifold, secondary cats, and ozone-reducing radiator and is SULEV II-compliant. The N52 without the secondary cats is Bin 5-compliant (i.e., LEV II) and is only available outside CARB-compliant states, but I'm not sure if maybe some of those states offer the ULEV II N52 by choice/default, or how exactly it works.

Also.... I think all Military Car Sales (MCS) orders get the ULEV cars - incase a service memebr is from one of those states that require ULEV spec/cars.

Greenkirby21 · 11-26-2012, 12:56 AM

sorry to bump an old thread guys but I wanted to hear everyones opinion on this since I don't know.

My car, an N52, has the lower picture from above, meaning I have both primary and secondary cats. I live in Texas, which I'm not even sure is a carb compliant state or not.

Anyways, I was wondering what happens if the secondary or primary cats are removed(pick one, not both).

I read online that removing the first set would yield the biggest gains as they are the most restrictive, but would it cause a CEL to occur or something of that sort? Would I fail the emissions test?

I read that removing the second set would yield little to no gain in power and just slightly increase the noise your car makes, and it also wouldn't produce any CEL or anything. Therefore, its not "worth it" to remove them, unless you want more sound.

I was just curious because I was searching through the forums and found this. I always wondered why my car has two sets of CATS, and if removing one would be beneficial or not.

Edit: Funny that my car has two cats and is considered ULEV-II.. it smells of gasoline when I turn on the car initially >_>

Southjersey128 · 11-26-2012, 08:01 PM

Quote:

Originally Posted by Greenkirby21

sorry to bump an old thread guys but I wanted to hear everyones opinion on this since I don't know.

My car, an N52, has the lower picture from above, meaning I have both primary and secondary cats. I live in Texas, which I'm not even sure is a carb compliant state or not.

Anyways, I was wondering what happens if the secondary or primary cats are removed(pick one, not both).

I read online that removing the first set would yield the biggest gains as they are the most restrictive, but would it cause a CEL to occur or something of that sort? Would I fail the emissions test?

I read that removing the second set would yield little to no gain in power and just slightly increase the noise your car makes, and it also wouldn't produce any CEL or anything. Therefore, its not "worth it" to remove them, unless you want more sound.

I was just curious because I was searching through the forums and found this. I always wondered why my car has two sets of CATS, and if removing one would be beneficial or not.

Edit: Funny that my car has two cats and is considered ULEV-II.. it smells of gasoline when I turn on the car initially >_>

I thought that the magna flow exhaust deleted the secondary cats on the 128 since it connects to the bottom of the exhaust manifold. Assuming you still have the mf cat back exhaust. If you did delete the primary cats you would get a cel.

Greenkirby21 · 11-26-2012, 08:10 PM

Quote:

Originally Posted by Southjersey128

I thought that the magna flow exhaust deleted the secondary cats on the 128 since it connects to the bottom of the exhaust manifold. Assuming you still have the mf cat back exhaust. If you did delete the primary cats you would get a cel.

I am pretty sure it goes to the second cats only. I can double check tomorrow by taking a peep under. But compare the two images.
EDIT: I have my old exhaust in the garage. the secondary cats are definately not there, so they are in the car

to what I have

Southjersey128 · 11-26-2012, 10:01 PM

I stand corrected. I thought the mf went all the way to the manifold. But since you do have the mf it would be easy for a muffler shop to just cut them out and put strait pipe in line. As long as the downstream o2 sensor is before the secondary cats there would be no cel either.

Greenkirby21 · 11-26-2012, 10:27 PM

Quote:

Originally Posted by Southjersey128

I stand corrected. I thought the mf went all the way to the manifold. But since you do have the mf it would be easy for a muffler shop to just cut them out and put strait pipe in line. As long as the downstream o2 sensor is before the secondary cats there would be no cel either.

Actually thank you for your help because otherwise I probably wouldn't have noticed xD. I will definitely talk to the people who installed my exhaust and get a quote from them and most likely get it removed if it doesn't give me any problems with legal and emissions.

Here in Texas, my county requires yearly emissions test, but they are done via OBD-II port. I will probably pass by the dealership (if I can be sneaky) and see what their exhaust looks like underneath for the other 128i.

If the other 128i on the dealership lot are missing these catalytic converters, then I will feel completely fine and should be able to remove them without any problems : ).

I looked at our 2012 X3, and that also has secondary catalytic converters(bottom picture says its for ULEV2 vehicles)

Wheras my moms car, a 2012 335i, has just the primary(but its an N55 and I think those come with a straight pipe since many people do N54 + N55 midpipes)

i just find it funny that putting my vin on realOEM also shows I shouldn't have them

jb2178 · 11-27-2012, 02:08 PM

You should do us all a favor and get a dyno done before and after. I'd really like to know what gains can be had from removing those extra cats. Not that it would be the same on my N51 but it would still be nice to have real numbers.

Greenkirby21 · 12-09-2012, 04:29 PM

Quote:

Originally Posted by jb2178

You should do us all a favor and get a dyno done before and after. I'd really like to know what gains can be had from removing those extra cats. Not that it would be the same on my N51 but it would still be nice to have real numbers.

According to this thread,

+9 HP and +3 Torque

http://www.e90post.com/forums/showthread.php?t=703329

06-26-2011, 01:56 PM	#1
NA_Villhauser New Member Drives: 2011 128i 6MT, sport pack Join Date: May 2011 Location: Lansing, MI Posts: 14 iTrader: (0)	Anyone's N52 have secondary cats? My understanding has been that the N51 has an extra pair of cats in addtion to the cats in the exhaust manifolds. It also is supposed to have lower compression and the two stage intake manifold to make up for any power loss from the extra cats and lowered compression. The different exhausts can be seen in the attached images from real oem. I noticed my 128i has the secondary cats shown for the N51 but does not have the two stage intake. According to my VIN I'm supposed to have an N52 and the block is stamped N52B30 right next to the serial number. I'm curious to know who else has these extra cats on an N52. Attached Images
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08-18-2011, 05:54 AM	#5
rvsixdriver New Member Drives: 2011 128i Join Date: Aug 2011 Location: Mandeville, LA Posts: 9 iTrader: (0)	This brings up questions I also have a 2011 6MT sport pack My exhaust system looks like the lower picture you posted. I saw in an earlier post that the n52 has ULEV and n51 has sulev II on the emissions sticker. Mine says ULEV II. I'm not too sure where the engine serial number is on my car, but I would guess I have the same setup you have. One question would be is it legal to eliminate one stage of a two stage system? Which one would you eliminate? How do I tell if I have a three stage intake? Last edited by rvsixdriver; 08-18-2011 at 10:43 PM.

11-26-2012, 12:56 AM	#16
Greenkirby21 Vrooom :) Drives: BMW 128i Join Date: Jun 2010 Location: Dream Land Posts: 1,737 iTrader: (1)	sorry to bump an old thread guys but I wanted to hear everyones opinion on this since I don't know. My car, an N52, has the lower picture from above, meaning I have both primary and secondary cats. I live in Texas, which I'm not even sure is a carb compliant state or not. Anyways, I was wondering what happens if the secondary or primary cats are removed(pick one, not both). I read online that removing the first set would yield the biggest gains as they are the most restrictive, but would it cause a CEL to occur or something of that sort? Would I fail the emissions test? I read that removing the second set would yield little to no gain in power and just slightly increase the noise your car makes, and it also wouldn't produce any CEL or anything. Therefore, its not "worth it" to remove them, unless you want more sound. I was just curious because I was searching through the forums and found this. I always wondered why my car has two sets of CATS, and if removing one would be beneficial or not. Edit: Funny that my car has two cats and is considered ULEV-II.. it smells of gasoline when I turn on the car initially >_> __________________ 2009 128i Coupe Crimson Red MODS: -Injen Intake-Magnaflow Exhaust-Carbon Fiber Spoiler - Carbon Fiber Grilles - OZ Ultraleggeras - CF Mirrors

11-26-2012, 10:01 PM	#19
Southjersey128 Private First Class Drives: 2008 128i Join Date: Mar 2011 Location: South Jersey Posts: 119 iTrader: (0)	I stand corrected. I thought the mf went all the way to the manifold. But since you do have the mf it would be easy for a muffler shop to just cut them out and put strait pipe in line. As long as the downstream o2 sensor is before the secondary cats there would be no cel either. __________________ AW, Coral, HID's, Afe Scoops and CAI, PBX, '09 Msport 18's, 225/255 Ventus V12's, (BMW Performance: BBK, Shifter Knob and Boot, E-Brake Handle, Steering Wheel, Front Strut Bar), E93 FSB, E92 RSB, M3 Rear Subframe Bushings, HPA coilover kit (Koni Adjustables and Swift Springs), Steel Brake Hoses, Black Kidneys, Smoked LED side markers, LED angel eyes, Blacklines, Carbon fiber spoiler(BMW Performance replica), Ambergones...

11-27-2012, 02:08 PM	#21
jb2178 Second Lieutenant Drives: 2008 128i Join Date: Jan 2008 Location: Riverview, FL Posts: 265 iTrader: (0)	You should do us all a favor and get a dyno done before and after. I'd really like to know what gains can be had from removing those extra cats. Not that it would be the same on my N51 but it would still be nice to have real numbers. __________________ Ordered: 128i Titanium Silver, Black Leatherette, High gloss black trim, Sport Package, iPod Adapter, Premium Audio, BMW Assist

06-26-2011, 04:53 PM	#2
Taymaishu Banned Drives: I love massive black cocks Join Date: Jul 2009 Location: in my ass and around my mouth Posts: 3,018 iTrader: (0) Garage List 2009 125i [2.75]	'09 N52 and no secondary cats.

06-27-2011, 12:13 PM	#3
AW128i Captain Drives: E82 N51 Join Date: Nov 2010 Location: Southeastern, PA Posts: 999 iTrader: (1)	My car is N51-equipped and it has the secondary cats under the car. It also has the 3-stage intake manifold, secondary air injection, and an ozone-fighting radiator coating, all of which help it achieve the SULEV II EPA rating. I can't verify the reduced compression ratio, but it's heavily rumored that the N51 does have a lower compression ratio than the comparable N52. I can tell you from personal experience piloting both engines that the N51 has a slightly but noticeably different power curve than a comparable N52.

06-27-2011, 03:53 PM	#4
NA_Villhauser New Member Drives: 2011 128i 6MT, sport pack Join Date: May 2011 Location: Lansing, MI Posts: 14 iTrader: (0)	I'm bummed that my car has the secondary cats but no 3-stage intake. My engine is clearly marked as an N52B30AE. Why would it have the extra cats?

08-18-2011, 07:12 AM	#6
AW128i Captain Drives: E82 N51 Join Date: Nov 2010 Location: Southeastern, PA Posts: 999 iTrader: (1)	According to the EPA's website, there are actually three versions of the 128i engine in the U.S.: Bin 5 N52 (Federal), ULEV II N52 (CARB), SULEV II N51 (CARB). This spans the entire E82 U.S. production (i.e., 2008-present). I'm guessing the CARB version of the N52 has the secondary cats and the Federal version does not.

08-19-2011, 09:53 AM	#9
Soccs New Member Drives: 125i Join Date: Jul 2011 Location: Portugal Posts: 20 iTrader: (0)	Hello, I am sorry for this noob question. but what the significant diference between each other? thank you

08-21-2011, 07:16 AM	#11
Soccs New Member Drives: 125i Join Date: Jul 2011 Location: Portugal Posts: 20 iTrader: (0)	Hello Greenkirby, the 3 stage manifold thanks

08-21-2011, 01:24 PM	#12
wolfe Lieutenant Drives: 128i M-Sport "Störtebeker" Join Date: Apr 2010 Location: USA Posts: 457 iTrader: (1)	'11 N52, and my exhaust looks like the lower picture too.

08-21-2011, 05:42 PM	#13
Dackelone Moderator Drives: 135i Silber mit/Rot 6MT N54 Join Date: Feb 2010 Location: Bayern, Germany Posts: 13,019 iTrader: (0)	It might be that the cars with the secondary cats are SULE cars (ie CA specs). ? The three stage intake manifold is also called: DISA. IF you google that you will find lots of info about how it works. BMW has used that DISA intake manifold on lots of other models as well. Some of the German tuners can reprogram the two stage intake (DISA too) to make a big Hp increase. Normally they can get around 275 PS with just a chip tune on a N52.

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