E90Post
 


Studio RSR
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > N54-Horrible catless downpipes smell



Reply
 
Thread Tools Search this Thread
      09-20-2018, 01:45 AM   #1
IISevv
Private First Class
United_States
37
Rep
111
Posts

Drives: 2007 335i FBO
Join Date: Jul 2017
Location: Scottsdale, AZ

iTrader: (0)

N54-Horrible catless downpipes smell

I just bought a full bolt-on 2007 335i and absolutely the car with one exception. It has catless downpipes with no secondary cats and there’s an extremely strong burnt gas smell from outside the car as well as inside at a stoplight with the windows down (It’s not a leak). I know that no cats will increase the smell but I have been in multiple 335’s with catless downpipes and none smelled this bad-any reason for this?
Appreciate 0
      09-20-2018, 06:23 AM   #2
dannyjones
Lieutenant
82
Rep
405
Posts

Drives: 2011 BMW 335i M-Sport
Join Date: Jan 2014
Location: Florida, USA

iTrader: (0)

My n55 smells awful too. I even had complaints at work from people entering the garage behind me
Appreciate 0
      09-20-2018, 09:13 AM   #3
Jonah335
Private First Class
54
Rep
115
Posts

Drives: 335i
Join Date: Apr 2015
Location: Florida

iTrader: (2)

I have a set of secondary cats OEM from my car if you would like to purchase. seems like the best option for you is to put secondaries back in so you can keep the free flow DP but reduce the smell. it doesn't bother me though
Appreciate 0
      09-20-2018, 09:16 AM   #4
Bullcitybmmer
Enlisted Member
25
Rep
38
Posts

Drives: 2013 335i e92 msport
Join Date: Mar 2016
Location: Durham NC

iTrader: (0)

The smell on my N55 grossed me out as well right after I put on catless DPs. I wound up going to a muffler shop and having 2 tiny high flow cats welded in really close to where earlier E9Xs had secondary cats. It really took the edge off and has made no noticeable difference to performance.
Appreciate 0
      09-20-2018, 09:47 AM   #5
Socket
Lieutenant General
Socket's Avatar
4525
Rep
11,898
Posts

Drives: 335i
Join Date: Nov 2014
Location: Australia

iTrader: (4)

Garage List
2008 BMW E92  [0.00]
Quote:
Originally Posted by IISevv View Post
I just bought a full bolt-on 2007 335i and absolutely the car with one exception. It has catless downpipes with no secondary cats and there’s an extremely strong burnt gas smell from outside the car as well as inside at a stoplight with the windows down (It’s not a leak). I know that no cats will increase the smell but I have been in multiple 335’s with catless downpipes and none smelled this bad-any reason for this?
N54 right not N55?
Appreciate 0
      09-20-2018, 10:41 AM   #6
TheMidnightNarwhal
Major General
TheMidnightNarwhal's Avatar
Canada
2593
Rep
6,226
Posts

Drives: 11' 335is DCT
Join Date: Jun 2015
Location: Gatineau, Quebec

iTrader: (0)

Quote:
Originally Posted by IISevv View Post
I just bought a full bolt-on 2007 335i and absolutely the car with one exception. It has catless downpipes with no secondary cats and there’s an extremely strong burnt gas smell from outside the car as well as inside at a stoplight with the windows down (It’s not a leak). I know that no cats will increase the smell but I have been in multiple 335’s with catless downpipes and none smelled this bad-any reason for this?
Well you said you don't have second cats. Maybe the 335s you have been in only had downpipes and still 2nd cats?
Appreciate 0
      09-20-2018, 11:34 AM   #7
nsjames
Brigadier General
2440
Rep
4,333
Posts

Drives: 08 328xi Touring
Join Date: May 2017
Location: ohio

iTrader: (0)

catless cars smell bad.

that's just how it is. There's a reason we put them on cars in the first place.
Appreciate 0
      09-20-2018, 01:46 PM   #8
IllSic_Design
Colonel
IllSic_Design's Avatar
United_States
2123
Rep
2,758
Posts

Drives: 09 E92 335i
Join Date: Jun 2016
Location: Northern California

iTrader: (1)

I still have secondary cats and never really notice the smell. Might want to put some back in.
Appreciate 0
      09-20-2018, 02:00 PM   #9
IISevv
Private First Class
United_States
37
Rep
111
Posts

Drives: 2007 335i FBO
Join Date: Jul 2017
Location: Scottsdale, AZ

iTrader: (0)

I figured. Just didn’t know if it was normal or if it might just be running way too rich. I might just put 200 cell secondary cats in if it gets too much.

Last edited by IISevv; 09-20-2018 at 02:14 PM..
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 08:20 PM.




e90post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST