Factory catalytic converter cell ratings

Rapture · 11-15-2010, 08:37 AM

Just curious if anyone knows what the cell rating on the factory primary and secondary cats are?

rd4LLe92m3 · 11-15-2010, 09:19 AM

400

LateBraking · 11-15-2010, 11:41 AM

Are they? I thought they were 400/200? That's what I heard somewhere, without hard evidence though so I definitely could be wrong!

rd4LLe92m3 · 11-15-2010, 02:25 PM

The primary cats are 400. I dont know about the secondary cats. I apologize for not seeing that portion of the post, but you are most likely correct. My bad.

Malek@MRF · 11-15-2010, 02:43 PM

400/200

Rapture · 11-15-2010, 04:51 PM

So, in theory I could remove the front cats, replace them with the rear cats, move the x-pipe up a foot or two, add some resonators and I have an "aftermarket" x-pipe?

I see all the aftermarket x-pipes with 200-300 cell primary cats and they promise no CEL so I am figuring replacing the factory primary with the factory secondaries will work.

Also, does a "hi-flow" aftermarket 200-300 cell cat flow the same as the "regular" flow 200 cell secondary factory cats?

dvpouldar26 · 11-15-2010, 05:25 PM

Stock primaries are 400 cell. Some with 200 cell aftermarket cats have still thrown a CEL. Matters on the brand and where the O2 bungs are placed. Friend of mine is running 200cell magnaflow cats and threw a CEL after a few hundred miles.

Rapture · 11-15-2010, 05:43 PM

I agree on the O2 sensor placement. Every manufacturer seems to do it differently and I don't know which is best for power/reading properly/no CEL. Guess some more research is due.

dvpouldar26 · 11-15-2010, 07:02 PM

Quote:

Originally Posted by Rapture

I agree on the O2 sensor placement. Every manufacturer seems to do it differently and I don't know which is best for power/reading properly/no CEL. Guess some more research is due.

Not only O2 bung placement, but also, some brands use foulers while others dont. I've learned that your best bet to avoid a CEL is just to get an Akrapovic delete-R or a tune. It is too much of a guessing game sometimes with diff. brand hfc's. The only promising brand that avoids CEL's so far is fabspeed, but im pretty sure there are cases where some of their x-pipes have thrown CEL's also.

Rapture · 11-15-2010, 07:12 PM

I am planning on an ECU tune in the future but am looking for some cheap and reliable (read: no CEL) power in the meantime to hold me over.

Rapture · 11-15-2010, 07:16 PM

Quote:

Originally Posted by Rapture

Also, does a "hi-flow" aftermarket 200-300 cell cat flow the same as the "regular" flow 200 cell secondary factory cats?

bump, anyone with any input on this?

aus · 11-15-2010, 07:17 PM

Since you're in the OC, Mesa Muffler in Costa Mesa on Harbor can cut out the secondary cats to just after the X-pipe for around $200 out the door.
I'm sure it would be even cheapr to cut out he primary cats only.
They were very impressed with the BMW exhaust quality.

Rapture · 11-15-2010, 07:21 PM

Quote:

Originally Posted by aus

Since you're in the OC, Mesa Muffler in Costa Mesa on Harbor can cut out the secondary cats to just after the X-pipe for around $200 out the door.
I'm sure it would be even cheapr to cut out he primary cats only.
They were very impressed with the BMW exhaust quality.

Thanks for the recommendation. I have access to a welder/fab shop so that's not a big deal. I have built quite a few exhausts in my day and modified the factory muffler myself a few weeks ago

aus · 11-16-2010, 05:57 PM

Quote:

Originally Posted by Rapture

Thanks for the recommendation. I have access to a welder/fab shop so that's not a big deal. I have built quite a few exhausts in my day and modified the factory muffler myself a few weeks ago

That's awesome.
Now if someone could just extent the O2 sensor cables, I'd be excited.

J08M3 · 11-16-2010, 07:24 PM

Fabspeed throws CEL

Rapture · 11-16-2010, 08:11 PM

Quote:

Originally Posted by J08M3

Fabspeed throws CEL

That sucks, but helps me lean toward keeping the front cats

aus · 11-17-2010, 02:01 AM

Gintani uses 300cpi cats that shouldn't throw a CE light.

Rapture · 11-17-2010, 04:34 AM

I was looking into that as well. I've heard good things about Gintani

325rider · 03-21-2013, 12:24 AM

Bumping this thread as the original question remained unanswered and the search button didn't provide me with an answer either.
My questions.

1) Do the OEM "Secondary 200 cell cats" PERFORM and/or FLOW similarly to "200 cell High flow/Race cats", or is there a large difference in efficiency or air flow due to better suited engineering performance in the "HFCs".

2) Does the position of the cats make a big difference? (not factoring CEL or O2 sensors, strictly speaking performance) i.e. The primary cats and HFCs in aftermarket systems are immediately behind the header flanges VERY early in the exhaust system as opposed to where the OEM secondary cats are. For example, would there be a difference in dyno performance, back pressure, or throttle response if you had HFCs at the beginning of the exhaust system, or where the OEM secondary cats are (hypothetically speaking, you have a muffler and are comparing just the location of the SAME HFCs given you have no other cats or resonators)

Lets get some replies from you brainiacs :|

11-15-2010, 08:37 AM	#1
Rapture I'm suckin gas but I'm haulin ass 57 Rep 783 Posts Drives: 2016 M3 ZCP MW/SO Join Date: Sep 2010 Location: OC, CA iTrader: (18)	Factory catalytic converter cell ratings Just curious if anyone knows what the cell rating on the factory primary and secondary cats are?
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11-15-2010, 09:19 AM	#2
rd4LLe92m3 Private First Class 10 Rep 121 Posts Drives: 08 JetBlack e92 M3 Join Date: Dec 2008 Location: Philly iTrader: (3)	400 __________________ 08 E92 M3/RE pulley/MS filter/EI x-pipe and HFC/GTS3 Front Bumper
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11-15-2010, 11:41 AM	#3
LateBraking Brigadier General 327 Rep 3,882 Posts Drives: Relatively Quick. Join Date: Sep 2008 Location: U.S.A. iTrader: (27)	Are they? I thought they were 400/200? That's what I heard somewhere, without hard evidence though so I definitely could be wrong!
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11-15-2010, 02:25 PM	#4
rd4LLe92m3 Private First Class 10 Rep 121 Posts Drives: 08 JetBlack e92 M3 Join Date: Dec 2008 Location: Philly iTrader: (3)	The primary cats are 400. I dont know about the secondary cats. I apologize for not seeing that portion of the post, but you are most likely correct. My bad. __________________ 08 E92 M3/RE pulley/MS filter/EI x-pipe and HFC/GTS3 Front Bumper
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11-15-2010, 02:43 PM	#5
Malek@MRF BimmerPost Supporting Vendor 732 Rep 3,735 Posts Drives: E92 M3, E46 M3, G82 M4 Join Date: Jan 2008 Location: Irvine, California iTrader: (5)	400/200 __________________ BMW PERFORMANCE SPECIALISTS. Race Engines. Suspension. F/I. Brakes. Race Preparation. Factory Service. Alignments. OFFICIAL PARTNERS: KW. MOTON. Brembo. AP Racing. BBS Motorsport. iND. HRE. Turner Motorsport. VAC. BMW Motorsport. Facebook \| Instagram \| Yelp! \| Flikr Phone: 949-233-0448 \| E-Mail: info@mrfengineering.com
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11-15-2010, 04:51 PM	#6
Rapture I'm suckin gas but I'm haulin ass 57 Rep 783 Posts Drives: 2016 M3 ZCP MW/SO Join Date: Sep 2010 Location: OC, CA iTrader: (18)	So, in theory I could remove the front cats, replace them with the rear cats, move the x-pipe up a foot or two, add some resonators and I have an "aftermarket" x-pipe? I see all the aftermarket x-pipes with 200-300 cell primary cats and they promise no CEL so I am figuring replacing the factory primary with the factory secondaries will work. Also, does a "hi-flow" aftermarket 200-300 cell cat flow the same as the "regular" flow 200 cell secondary factory cats?
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11-15-2010, 05:25 PM	#7
dvpouldar26 Major 64 Rep 1,498 Posts Drives: 2008 e92 328i, Porsche 987.1 Join Date: May 2008 Location: Beverly Hills, CA iTrader: (4)	Stock primaries are 400 cell. Some with 200 cell aftermarket cats have still thrown a CEL. Matters on the brand and where the O2 bungs are placed. Friend of mine is running 200cell magnaflow cats and threw a CEL after a few hundred miles. __________________ E92 328i Jet Black / Gloss Black Grilles / 8000k D1S low beam / 6000k HID fogs / GP Thunder 8500k angels & cornering bulbs / black reflectors / gloss black vinyled window trim / tints / smoked rear turn signals / black roundels / AC Schnitzer roof spoiler / VRS style decklid spoiler / Matte black Stripes / Rear fogs / matte mirrors / 19" LM reps / APR lip
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11-15-2010, 05:43 PM	#8
Rapture I'm suckin gas but I'm haulin ass 57 Rep 783 Posts Drives: 2016 M3 ZCP MW/SO Join Date: Sep 2010 Location: OC, CA iTrader: (18)	I agree on the O2 sensor placement. Every manufacturer seems to do it differently and I don't know which is best for power/reading properly/no CEL. Guess some more research is due.
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11-15-2010, 07:12 PM	#10
Rapture I'm suckin gas but I'm haulin ass 57 Rep 783 Posts Drives: 2016 M3 ZCP MW/SO Join Date: Sep 2010 Location: OC, CA iTrader: (18)	I am planning on an ECU tune in the future but am looking for some cheap and reliable (read: no CEL) power in the meantime to hold me over.
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11-15-2010, 07:17 PM	#12
aus Major General 893 Rep 9,034 Posts Drives: Odysse Join Date: Jul 2005 Location: Seal Beach, CA iTrader: (10)	Since you're in the OC, Mesa Muffler in Costa Mesa on Harbor can cut out the secondary cats to just after the X-pipe for around $200 out the door. I'm sure it would be even cheapr to cut out he primary cats only. They were very impressed with the BMW exhaust quality. __________________ Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."
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11-16-2010, 07:24 PM	#15
J08M3 Major General 286 Rep 6,007 Posts Drives: 2011 M3 COUPE Join Date: May 2008 Location: NEW YORK iTrader: (8)	Fabspeed throws CEL __________________
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11-17-2010, 02:01 AM	#17
aus Major General 893 Rep 9,034 Posts Drives: Odysse Join Date: Jul 2005 Location: Seal Beach, CA iTrader: (10)	Gintani uses 300cpi cats that shouldn't throw a CE light. __________________ Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."
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11-17-2010, 04:34 AM	#18
Rapture I'm suckin gas but I'm haulin ass 57 Rep 783 Posts Drives: 2016 M3 ZCP MW/SO Join Date: Sep 2010 Location: OC, CA iTrader: (18)	I was looking into that as well. I've heard good things about Gintani
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03-21-2013, 12:24 AM	#19
325rider Captain 36 Rep 826 Posts Drives: '11 e90 M3 6mt Join Date: Aug 2010 Location: Miami, Fl iTrader: (1)	Bumping this thread as the original question remained unanswered and the search button didn't provide me with an answer either. My questions. 1) Do the OEM "Secondary 200 cell cats" PERFORM and/or FLOW similarly to "200 cell High flow/Race cats", or is there a large difference in efficiency or air flow due to better suited engineering performance in the "HFCs". 2) Does the position of the cats make a big difference? (not factoring CEL or O2 sensors, strictly speaking performance) i.e. The primary cats and HFCs in aftermarket systems are immediately behind the header flanges VERY early in the exhaust system as opposed to where the OEM secondary cats are. For example, would there be a difference in dyno performance, back pressure, or throttle response if you had HFCs at the beginning of the exhaust system, or where the OEM secondary cats are (hypothetically speaking, you have a muffler and are comparing just the location of the SAME HFCs given you have no other cats or resonators) Lets get some replies from you brainiacs :\|
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