N54Tech.com - International Turbo Racing Discussion
tylerd tylerd is offline
New Member
Posts: 7
Join Date: Jan 2017
Car: 135i
Default N55 ******* ** with N54 secondary cats - 05-04-2018, 07:22 AM

I asked this in another forum, but no one had any thoughts about it, so it seems.

I was thinking about getting a catted down/pipe from wagner, but read that the gains are less over a catt/ed down/pipe.

Problem is, I would still like to have a ca/t to prevent fuel smell etc.

So I thought why not take a ***/less down/pipe for better airflow directly after the turbo and then have the secondary underfloor cats of the N54?

Wouldnt that be the best of both worlds?

Does anyone know the how many cells the original underfloor cats have?

Thanks alot!

Edit: Whats wrong with the *** all the time?
Reply With Quote
Vorsprung_CJB's Avatar
Vorsprung_CJB Vorsprung_CJB is offline
Pessimistic Poster
Posts: 982
Join Date: Jun 2011
Car: 135i N54
Default 05-04-2018, 07:42 AM

I have heard of people doing that, but the mids can take some extra abuse in that setup since there is nothing upstream to help them out. If you aren't doing anything crazy it should be fine, but if you plan to run heavy meth/e85 or NLS type stuff, or track the car, you might want to check them from time to time. Honestly the N55 single downp's are pretty fat so it flows pretty well even with cats in most stock turbo situations I would think.

As far as the ***'s, BMS is based in California so there are some restrictions on certain emissions related keywords...
Reply With Quote
prime300's Avatar
prime300 prime300 is offline
New Member
Posts: 7
Join Date: Sep 2017
Car: E90 335i xDrive N55
Default 05-07-2018, 03:53 PM

Dunno what car ure driving but the xDrive e9x chassis with N55 got second cats... i personally have no ***s only the 2nd & the smell is not that bad(i have e90 335 xDrive 2011)

Paul C.
Reply With Quote
Stoolz Stoolz is offline
Senior Member
Posts: 845
Join Date: Jan 2015
Car: 11 135i
Default 05-07-2018, 07:49 PM

I did this but with custom ones welded onto the BMW PE Y piece. (Or thereabouts).
Sounds WAY better and smells heaps better. No performanceloss to speak of.

2011 135i Dct coupe Alpine white n blacked out.
VTT DBB,Pure Inlet, JB4,GFB DV+,MHD,Fuel-it Platinum PI with Cm 5 - 50:50 Meth, E85, N20 tmap, Fuel It S2 lpfp, KB Boost A Spark, BMS IC /CP / IT / OCC, SG Boost Pipe, Quaife LSD, Federal RS-RR,M4 Flywheel, SSP R spec clutches, Kw V3 & Pro rolled guards, AR CL **, Bmw PE. Custom mi**ipe kitties. 1000wrms custom audio.
Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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

Forum Jump

vBulletin Skin developed by: vBStyles.com
Copyright 2007 - 2018, N54tech.com