Catless Downpipe smell

matty088 · 02-14-2018, 06:47 AM

Well I messed up. I didnt realize the CAT in the DP is the only cat in the exhaust system on a 435xi.

I thought it was a precat that was used simply on start up to clean the air while stuff is cold.

My question is this. How bad is the smell when running a catless DP? I know this subjective. however what are we talking about here? Are my clothes going to stink? Or do you smell it only under certain instances like when warming car up in morning or if sitting in traffic? This is my daily. Am I gonna pass out at stop lights or not want to take my children in it?

mbanks21 · 02-14-2018, 07:34 AM

I've never had any complaints and I run catless with res delete and 4 gallons of E85. My wife is a bloodhound and she's never said anything about it.

Zentan · 02-14-2018, 07:40 AM

No problems at all with me. I don't mind the smell. The only time you will really smell the fume is when you're sitting in traffic with the windows down, and obviously when you're outside behind the car.

ChubbyWilly · 02-14-2018, 07:58 AM

I smell it but it doesn't get on my clothes. Then again i'm straight piped with a resonator so it's much worse for me.

matty088 · 02-14-2018, 08:21 AM

you guys with catless is this your daily?

thanks or replies

mbanks21 · 02-14-2018, 08:35 AM

Sure is

Ultimateone · 02-14-2018, 09:09 AM

It really smells when you're actually driving behind a catless car, you'd be surprised.

ceedawg · 02-14-2018, 09:41 AM

Quote:

Originally Posted by Zentan

No problems at all with me. I don't mind the smell. The only time you will really smell the fume is when you're sitting in traffic with the windows down, and obviously when you're outside behind the car.

This!100%

matty088 · 02-14-2018, 11:16 AM

the fabspeed high flow cat is some piece of art. I saw a review where it gave a m2 30whp without a tune. I am shocked. how could this be. its still a brick in the middle of the exhaust.

kern417 · 02-14-2018, 11:39 AM

Quote:

Originally Posted by Ultimateone

It really smells when you're actually driving behind a catless car, you'd be surprised.

this. it's an obvious smell, just not as obvious from inside the car. as long as there are no exhaust leaks, you really shouldn't smell it unless your windows are open and the wind blows in the right direction. also if you start your car up in the morning and let it warm up in the garage, even with the garage door open you can smell it a bit.

Zara · 02-14-2018, 12:22 PM

I only smell mine when I start it up in the garage or stand directly behind the car. Other than that the smell isn't that noticeable for me.

paimon.soror · 02-14-2018, 12:24 PM

Quote:

Originally Posted by matty088

the fabspeed high flow cat is some piece of art. I saw a review where it gave a m2 30whp without a tune. I am shocked. how could this be. its still a brick in the middle of the exhaust.

lower cell count = more cfm

more cfm = less restriction

less restriction = more power

yoon_209 · 02-14-2018, 01:08 PM

i have catless dp as a DD it definitely has a very strong smell. You only smell it on idle with the windows down tho. I've even had a lot of passengers mention the smell to me. It won't stain your clothes

i dont recommend warming your car in the with the garage closed, it will become a hotbox of fumes

matty088 · 02-14-2018, 01:24 PM

seems like this fabspeed is a viable solution. I already have a catless dp...thinking i may juts run it for a couple years

badbread · 02-14-2018, 01:41 PM

I just recently upgraded to a CAT-less and the smell isn't as bad as I thought it would be.

The wife hasn't mentioned the smell yet.

My 7 year old last night said "eww it smells like a homeless person in here (garage)", for whatever that's worth.

I think the type/quality of fuel may have something to do with the smell, as with E85 I've found it doesn't smell quite as much.

paimon.soror · 02-14-2018, 02:18 PM

Quote:

Originally Posted by badbread

My 7 year old last night said "eww it smells like a homeless person in here (garage)", for whatever that's worth..

Calvin36 · 02-14-2018, 03:53 PM

Quote:

Originally Posted by Ultimateone

It really smells when you're actually driving behind a catless car, you'd be surprised.

This. RIP the guy stuck behind you in traffic. Haha

ceedawg · 02-14-2018, 07:11 PM

Quote:

Originally Posted by matty088

the fabspeed high flow cat is some piece of art. I saw a review where it gave a m2 30whp without a tune. I am shocked. how could this be. its still a brick in the middle of the exhaust.

Two high flow cats on my AMG/MB with exhaust headers and soft ware went from 276whp to 307whp Mustang dyno(heart breaker) with a beautiful area under the curve. Thats about 290whp to 327whp on a dynojet. Two high flow cats N/A 5.4l motor

kevinjt · 02-15-2018, 06:20 AM

I actually don't mind the smell. I secretly like it when I use Race gas

ER Catless DP here.

Calvin36 · 02-15-2018, 03:28 PM

Quote:

Originally Posted by kevinjt

I actually don't mind the smell. I secretly like it when I use Race gas

ER Catless DP here.

Because racecar right? haha Need to smell the gas to make it a racecar!

matty088 · 02-15-2018, 05:11 PM

But it's not a racecar. It's a commuter car with some balls and great handling

ceedawg · 02-15-2018, 06:42 PM

Quote:

Originally Posted by matty088

But it's not a racecar. It's a commuter car with some balls and great handling

Just leave the stock cat on and be done then if you have concerns about burnt gas smells.

I'm sure your car will still run strong with SW tune upgrade.

02-14-2018, 06:47 AM	#1
matty088 Major 362 Rep 1,206 Posts Drives: 335i Join Date: Jan 2012 Location: Ct iTrader: (1)	Catless Downpipe smell Well I messed up. I didnt realize the CAT in the DP is the only cat in the exhaust system on a 435xi. I thought it was a precat that was used simply on start up to clean the air while stuff is cold. My question is this. How bad is the smell when running a catless DP? I know this subjective. however what are we talking about here? Are my clothes going to stink? Or do you smell it only under certain instances like when warming car up in morning or if sitting in traffic? This is my daily. Am I gonna pass out at stop lights or not want to take my children in it?
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02-14-2018, 07:34 AM	#2
mbanks21 Colonel 1268 Rep 2,957 Posts Drives: 2015 335i MSport Join Date: Aug 2013 Location: High Bridge, NJ iTrader: (8)	I've never had any complaints and I run catless with res delete and 4 gallons of E85. My wife is a bloodhound and she's never said anything about it. __________________ 2015 335i Msport/6 JB4/EWG/E30/VRSF DP/ER CP/ VRSF Race Exhaust/ Injen Intake/Verde Axis 19x8.5/9.5 245/35/275/30 Conti Extreme CS/ H&R Sports / Motorsport Hardware Stud Conversion
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02-14-2018, 07:40 AM	#3
Zentan First Lieutenant 132 Rep 302 Posts Drives: 2019 M2C / 6MT / SO Join Date: Apr 2017 Location: Queens, NY iTrader: (0)	No problems at all with me. I don't mind the smell. The only time you will really smell the fume is when you're sitting in traffic with the windows down, and obviously when you're outside behind the car.
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02-14-2018, 07:58 AM	#4
ChubbyWilly First Lieutenant 105 Rep 327 Posts Drives: 2015 BMW 335i Join Date: Apr 2014 Location: DFW iTrader: (0)	I smell it but it doesn't get on my clothes. Then again i'm straight piped with a resonator so it's much worse for me. __________________ Mods: MHD Stage 2+ FlexFuel, xHP Stage 3, VRSF 5" HD Intercooler, VRSF Charge Pipe, CircuitWerks Catless DP, AFE Pro Dry S Intake filter, Eldor coils, NGK 97506 @ .026, Bilstein B14 coils.
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02-14-2018, 08:21 AM	#5
matty088 Major 362 Rep 1,206 Posts Drives: 335i Join Date: Jan 2012 Location: Ct iTrader: (1)	you guys with catless is this your daily? thanks or replies
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02-14-2018, 08:35 AM	#6
mbanks21 Colonel 1268 Rep 2,957 Posts Drives: 2015 335i MSport Join Date: Aug 2013 Location: High Bridge, NJ iTrader: (8)	Sure is __________________ 2015 335i Msport/6 JB4/EWG/E30/VRSF DP/ER CP/ VRSF Race Exhaust/ Injen Intake/Verde Axis 19x8.5/9.5 245/35/275/30 Conti Extreme CS/ H&R Sports / Motorsport Hardware Stud Conversion
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02-14-2018, 09:09 AM	#7
Ultimateone OG E46Fanatic 173 Rep 845 Posts Drives: 24 Champ White CTR Join Date: Dec 2014 Location: Boston, MA iTrader: (4)	It really smells when you're actually driving behind a catless car, you'd be surprised.
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02-14-2018, 11:16 AM	#9
matty088 Major 362 Rep 1,206 Posts Drives: 335i Join Date: Jan 2012 Location: Ct iTrader: (1)	the fabspeed high flow cat is some piece of art. I saw a review where it gave a m2 30whp without a tune. I am shocked. how could this be. its still a brick in the middle of the exhaust.
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02-14-2018, 12:22 PM	#11
Zara Lieutenant 611 Rep 434 Posts Drives: 2014 335i Join Date: Jun 2017 Location: Chicago iTrader: (1)	I only smell mine when I start it up in the garage or stand directly behind the car. Other than that the smell isn't that noticeable for me. __________________ 2014 335i 6MT /// Mineral Gray - Red Coral \| M Perf Spoiler \| M Perf Lip & Diffuser \| M Perf Grilles \| M Perf Side Splitters \| M Perf CF & Alcantra Interior Trim \| \| Wagner Evo II FMIC \| VRSF DP \| AA CP \| CTS Turbo Intake \| MHD Stage 2 Tune \| H&R Sports \| Bilstein B8s \|
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02-14-2018, 01:08 PM	#13
yoon_209 Masterchief 362 Rep 1,011 Posts Drives: 20' BMW M340i Join Date: Aug 2016 Location: Irvine, CA iTrader: (1)	i have catless dp as a DD it definitely has a very strong smell. You only smell it on idle with the windows down tho. I've even had a lot of passengers mention the smell to me. It won't stain your clothes i dont recommend warming your car in the with the garage closed, it will become a hotbox of fumes __________________ AWE Non-Res Touring \| TE37 SL PW \| Ohlins RT
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02-14-2018, 01:24 PM	#14
matty088 Major 362 Rep 1,206 Posts Drives: 335i Join Date: Jan 2012 Location: Ct iTrader: (1)	seems like this fabspeed is a viable solution. I already have a catless dp...thinking i may juts run it for a couple years
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02-14-2018, 01:41 PM	#15
badbread not good, but bad 333 Rep 361 Posts Drives: 2013 335i Join Date: Jun 2016 Location: Bay Area, CA iTrader: (3)	I just recently upgraded to a CAT-less and the smell isn't as bad as I thought it would be. The wife hasn't mentioned the smell yet. My 7 year old last night said "eww it smells like a homeless person in here (garage)", for whatever that's worth. I think the type/quality of fuel may have something to do with the smell, as with E85 I've found it doesn't smell quite as much. __________________ They are spelled BRAKES not breaks!!!! Oh FFS, not another spark plug thread! BreadsBMW on Youtube
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02-15-2018, 06:20 AM	#19
kevinjt First Lieutenant 152 Rep 352 Posts Drives: 335i M-Sport 14' Join Date: May 2016 Location: Puerto Rico iTrader: (1)	I actually don't mind the smell. I secretly like it when I use Race gas ER Catless DP here. __________________ __________________ 335i EB RWD \| ///M Sport Pkg \| BMS Intake \| M Performance Exhaust \| ER Catless Downpipe \| ER FMIC \| ER Charge pipe \| CF Aero \| 19" Black M4 Wheels \| Candy Orange ///M Brake Calipers \| ///M Steering wheel \| ///M Metal Pedals \| Euro Spec - LCI Taillights
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02-15-2018, 05:11 PM	#21
matty088 Major 362 Rep 1,206 Posts Drives: 335i Join Date: Jan 2012 Location: Ct iTrader: (1)	But it's not a racecar. It's a commuter car with some balls and great handling
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