difference between catted and catless

2doubleeagle · 02-06-2012, 06:30 AM

Hey guys, I am about to start modding my car and have a question. I have learned much from this forum, but I have not been able to determine what exactly are the differences between catted and catless downpipes aside from the obvious. I believe I read somewhere that you will get more of a smell from catless? Is there much difference in performance between the two? Are people running catted mainly to pass emmissions? I live in Florida so that is not an issue. Thanks in advance

cn555ic · 02-06-2012, 06:55 AM

If you lIve in Florida which has no emission testing go with catless

BQTuning · 02-06-2012, 07:03 AM

Per dyno data there is only about 5 HP difference. However though that will depend on who the manufacture is for the catted DPs. AR Design is one of them that according to their data specs shows a very small marginal between the two.

For me, if I am going to go with AR Design I would just get the "HIGH-FLOW" DP race cats.

Many people prefer the catless mainly because its cheaper and of course for the extra gain for whatever its worth.

RoundelM3 · 02-06-2012, 07:53 AM

Other thing to consider, depending on how the State you reside in regards such things, is that removing catalytic converters constitutes tampering with federally-mandated emissions controls, which can carry up to a $10K fine if someone wanted to jack you up for that. That would end up being a VERY expensive mod!

zerep1 · 02-06-2012, 07:58 AM

you live in florida get catless and leave your secondary if your worried about the police they wont be able to smell anything

fl335i · 02-06-2012, 08:24 AM

I'm wondering if the check engine light will come on or not, with the OEM computer, Dinan and JB tuners.

skatenc123 · 02-06-2012, 08:41 AM

if you dont have a tune youll get a cel. i have cobb and i dont get one. idk about other tunes though.

RnmEvo9 · 02-06-2012, 08:43 AM

Quote:

Originally Posted by fl335i

I'm wondering if the check engine light will come on or not, with the OEM computer, Dinan and JB tuners.

I can only speak about JB4 and Cobb tunes as I've had experience with both, and they can both eliminate the check engine light from downpipes.

OEM will throw the check engine light within 15 miles or so.

JamesM3M5 · 02-06-2012, 09:08 AM

You may need a "downpipe fix" to get around the catless DPs on the Dinan tune, since it retains full OBD2 checks.

In FL, just go catless. No emissions, no one gives a crap down there. Slightly better spool and higher power without cats, and high flow cats can still go bad from contamination with leaded fuel or (rumored) high meth concentrations if you go that route.

enrita · 02-06-2012, 09:19 AM

nice another catted vs uncatted dps thread

nitehawk · 02-06-2012, 09:25 AM

Quote:

Originally Posted by JamesM3M5

In FL, just go catless. No emissions, no one gives a crap down there.

So, in Florida, there is no emissions reinforcement whatsoever? Not even an OBD check every few years?

It's amazing how much variance there is between state to state or province; from tailpipe sniffers on a rolling dyno, to OBD check to nothing

Squintz82 · 02-06-2012, 10:19 AM

I'm new to this as well, but does anyone make O2 simulators so you don't throw a CEL with a stock tune and no cats? I'm curious because I may have to remove any tuning for warranty work.

JamesM3M5 · 02-06-2012, 10:22 AM

Quote:

Originally Posted by nitehawk

So, in Florida, there is no emissions reinforcement whatsoever? Not even an OBD check every few years?

It's amazing how much variance there is between state to state or province; from tailpipe sniffers on a rolling dyno, to OBD check to nothing

LOTS of people with not-so-street-legal cars have them registered in FL. Very lenient.

JamesM3M5 · 02-06-2012, 10:24 AM

Quote:

Originally Posted by Squintz82

I'm new to this as well, but does anyone make O2 simulators so you don't throw a CEL with a stock tune and no cats? I'm curious because I may have to remove any tuning for warranty work.

Look for "downpipe fix". http://www.burgertuning.com/dpfix.html

RnmEvo9 · 02-06-2012, 10:24 AM

Quote:

Originally Posted by nitehawk

So, in Florida, there is no emissions reinforcement whatsoever? Not even an OBD check every few years?

It's amazing how much variance there is between state to state or province; from tailpipe sniffers on a rolling dyno, to OBD check to nothing

I've been catless for over a decade with no issues (different turbo cars).

Squintz82 · 02-06-2012, 10:27 AM

Quote:

Originally Posted by JamesM3M5

Look for "downpipe fix". http://www.burgertuning.com/dpfix.html

Thanks

Is this detectable by dealers?

Brey335i · 02-06-2012, 10:30 AM

Quote:

Originally Posted by Squintz82

Thanks

Is this detectable by dealers?

Yes if they so wish to investigate.

2doubleeagle · 02-06-2012, 02:17 PM

Thanks for all the info guys. I will go with catless, cobb and fmic. Hopefully that will satisfy me for awhile

JamesM3M5 · 02-06-2012, 03:13 PM

Those are the top 3 power mods. I think you'll be happy.

02-06-2012, 06:30 AM	#1
2doubleeagle Enlisted Member 5 Rep 41 Posts Drives: 2015 mw m3 Join Date: Nov 2010 Location: Sorrento, Fl. iTrader: (0)	difference between catted and catless Hey guys, I am about to start modding my car and have a question. I have learned much from this forum, but I have not been able to determine what exactly are the differences between catted and catless downpipes aside from the obvious. I believe I read somewhere that you will get more of a smell from catless? Is there much difference in performance between the two? Are people running catted mainly to pass emmissions? I live in Florida so that is not an issue. Thanks in advance
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02-06-2012, 06:55 AM	#2
cn555ic 441 Rep 18,331 Posts Drives: 335i Join Date: Jun 2007 Location: US iTrader: (6)	If you lIve in Florida which has no emission testing go with catless
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02-06-2012, 07:03 AM	#3
BQTuning Banned 469 Rep 4,392 Posts Drives: 2012 Z4 sDrive35i M Sport 6MT Join Date: Nov 2010 Location: bq@bqtuning.com iTrader: (0)	Per dyno data there is only about 5 HP difference. However though that will depend on who the manufacture is for the catted DPs. AR Design is one of them that according to their data specs shows a very small marginal between the two. For me, if I am going to go with AR Design I would just get the "HIGH-FLOW" DP race cats. Many people prefer the catless mainly because its cheaper and of course for the extra gain for whatever its worth.
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02-06-2012, 07:53 AM	#4
RoundelM3 Major General 1837 Rep 6,990 Posts Drives: 15 F80 M3, 22 G01 X3 30i Join Date: Apr 2010 Location: Clayton, NC iTrader: (2) Garage List 2022 BMW X3 [9.83] 2015 BMW M3 [6.50]	Other thing to consider, depending on how the State you reside in regards such things, is that removing catalytic converters constitutes tampering with federally-mandated emissions controls, which can carry up to a $10K fine if someone wanted to jack you up for that. That would end up being a VERY expensive mod! __________________ 2015 F80 ///M3 Sedan 7DCT Tanzanite, 2022 X3 sDrive30i 8AT Brooklyn Grey
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02-06-2012, 07:58 AM	#5
zerep1 Lieutenant 40 Rep 462 Posts Drives: 335i E90, 328i F30, 230i G42, Join Date: Nov 2010 Location: Tampa, Florida iTrader: (1)	you live in florida get catless and leave your secondary if your worried about the police they wont be able to smell anything __________________ Irub
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02-06-2012, 08:24 AM	#6
fl335i Captain 146 Rep 942 Posts Drives: 335i Join Date: Oct 2010 Location: FL iTrader: (2)	I'm wondering if the check engine light will come on or not, with the OEM computer, Dinan and JB tuners. __________________ '07 335i Sedan, base pkg, 6spd Manual, Procede 3 V5 w/NLS, Macht Schnell Downpipes, 18" Staggered 313's w/Conti DWS's, OS Giken TCD LSD, VAC Street Diff Cover, Dinan Oil Cooler, Dinan Intercooler, Akebono Euro Pads, CDV Removed, Black BMW Grilles, Interior & Exterior white LED lighting, LUX Angel Eyes, Debadged, Blend V1 mount, Llumar ATR Tint.
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02-06-2012, 08:41 AM	#7
skatenc123 Captain 11 Rep 645 Posts Drives: 2007 335i coupe Join Date: Jan 2012 Location: NC iTrader: (1)	if you dont have a tune youll get a cel. i have cobb and i dont get one. idk about other tunes though.
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02-06-2012, 09:08 AM	#9
JamesM3M5 Some dude 92 Rep 1,780 Posts Drives: E92 335i Join Date: Sep 2011 Location: Northern VA iTrader: (0)	You may need a "downpipe fix" to get around the catless DPs on the Dinan tune, since it retains full OBD2 checks. In FL, just go catless. No emissions, no one gives a crap down there. Slightly better spool and higher power without cats, and high flow cats can still go bad from contamination with leaded fuel or (rumored) high meth concentrations if you go that route. __________________ RRT E92 335i/6MT with stuff and things
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02-06-2012, 09:19 AM	#10
enrita Major General 161 Rep 7,377 Posts Drives: 335i - Big turbos Join Date: Sep 2008 Location: Italian in Sweden iTrader: (0)	nice another catted vs uncatted dps thread __________________ 07 335i AT - MOTIV 750 - MHD E85 BMS flash - BMS PI - JB4G5 - Okada Coils - NGK 5992 Plugs - Helix IC - Snow Stg. 3 - Stett CP - Custom midpipes with 100 HJS Cats - Bastuck Quad - PSS10 - QUAIFE LSD - BMS OCC - Forge DVs - AR OC - ALCON BBK - M3 Chassi - Dinan CP - Velocity M rear Toe arms - Advan RZ-DF - LUX H8 - Level 10 AT upgrade
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02-06-2012, 10:19 AM	#12
Squintz82 Private First Class 7 Rep 117 Posts Drives: 2008 TiAg E92 335i Join Date: Nov 2010 Location: Long Island, NY iTrader: (4)	I'm new to this as well, but does anyone make O2 simulators so you don't throw a CEL with a stock tune and no cats? I'm curious because I may have to remove any tuning for warranty work.
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02-06-2012, 02:17 PM	#18
2doubleeagle Enlisted Member 5 Rep 41 Posts Drives: 2015 mw m3 Join Date: Nov 2010 Location: Sorrento, Fl. iTrader: (0)	Thanks for all the info guys. I will go with catless, cobb and fmic. Hopefully that will satisfy me for awhile
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02-06-2012, 03:13 PM	#19
JamesM3M5 Some dude 92 Rep 1,780 Posts Drives: E92 335i Join Date: Sep 2011 Location: Northern VA iTrader: (0)	Those are the top 3 power mods. I think you'll be happy. __________________ RRT E92 335i/6MT with stuff and things
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