F30POST
F30POST
2012-2015 BMW 3-Series and 4-Series Forum
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST > Technical Forums > N55 Turbo Engine / Drivetrain / Exhaust Modifications > Options if I remove my c4tless downpipe (F30 335i EWG JB4)
GetBMWParts
Post Reply
 
Thread Tools Search this Thread
      03-22-2018, 08:26 PM   #1
M3AWD
Lieutenant Colonel
M3AWD's Avatar
United_States
3178
Rep
1,902
Posts

Drives: 2022 G80 M3 AWD
Join Date: Sep 2013
Location: Atlanta, GA

iTrader: (0)

Options if I remove my c4tless downpipe (F30 335i EWG JB4)

I've had my 2014 F30 335i (EWG) for over 4 years and been running the following mods for almost 1.5 years:

JB4 with EWG & Flex connectors
BMS Intake
VRSF c4tless downpipe
VRSF chargepipe
E85 mix (~E25?)
Map 5 and hitting ~16+psi
Old JB4 firmware with no CEL

Car pulls hard and I really love it. I've surprised many other higher powered cars but I'm not trying to brag about kill stories here. But the c4tless dp has become a bit of a headache as it needs to be removed for emissions and the car stinks specially in my garage and in traffic with windows down.

I want to look into other mod options either with stock cats or good aftermarket cats with no CEL. I'm open to suggestions but I'm interested in similar power levels as my current setup. I'm flexible so let me know what you think. I'd like to keep this car for a couple more years!
__________________

2022 G80 M3 Comp M xDrive
Appreciate 0
      03-23-2018, 03:50 AM   #2
enemigo13
Lieutenant
247
Rep
500
Posts

Drives: F32 LCI 440xi citrineblack
Join Date: Nov 2015
Location: LT

iTrader: (0)

how much you think you will loose max hp (not midrange but max hp) installing stock dp on? probably 10hp, but not 20-30whp like downpipe sellers declare.

Quote:
Originally Posted by M-SP0RT View Post
I've had my 2014 F30 335i (EWG) for over 4 years and been running the following mods for almost 1.5 years:

JB4 with EWG & Flex connectors
BMS Intake
VRSF c4tless downpipe
VRSF chargepipe
E85 mix (~E25?)
Map 5 and hitting ~16+psi
Old JB4 firmware with no CEL

Car pulls hard and I really love it. I've surprised many other higher powered cars but I'm not trying to brag about kill stories here. But the c4tless dp has become a bit of a headache as it needs to be removed for emissions and the car stinks specially in my garage and in traffic with windows down.

I want to look into other mod options either with stock cats or good aftermarket cats with no CEL. I'm open to suggestions but I'm interested in similar power levels as my current setup. I'm flexible so let me know what you think. I'd like to keep this car for a couple more years!
Appreciate 0
      03-23-2018, 04:38 AM   #3
bmwchue
Captain
242
Rep
804
Posts

Drives: 2013 bmw 328i
Join Date: Oct 2017
Location: California

iTrader: (0)

Maybe a catted downpipe bit its pricey
Appreciate 0
      03-23-2018, 05:04 AM   #4
bradsm87
Lieutenant Colonel
Australia
592
Rep
1,693
Posts

Drives: F25 LCI xDrive30d
Join Date: Jun 2013
Location: Australia

iTrader: (0)

Keep the catless downpipe, ditch the JB4 and get a proper flash tune. MHD or Bootmod3.
Appreciate 0
      03-23-2018, 05:07 AM   #5
Wibbles
Coding ECU's remotely
Wibbles's Avatar
439
Rep
1,169
Posts

Drives: M3LR
Join Date: May 2012
Location: UK

iTrader: (0)

300 Cell Sports Cat may be the answer.
__________________
Author of Car Connector - remote ICOM & ENET tool - Built in VPN for easy coding and remote diagnostics
Car Connector on YouTube
Appreciate 0
      03-23-2018, 06:44 AM   #6
Whistlefist
Enlisted Member
27
Rep
36
Posts

Drives: 2014 335i Msport
Join Date: Mar 2017
Location: Cranberry Township, PA

iTrader: (0)

Quote:
Originally Posted by bradsm87 View Post
Keep the catless downpipe, ditch the JB4 and get a proper flash tune. MHD or Bootmod3.
How exactly will that help him with emissions checks or the smell?
Appreciate 2
      03-23-2018, 11:24 AM   #7
M3AWD
Lieutenant Colonel
M3AWD's Avatar
United_States
3178
Rep
1,902
Posts

Drives: 2022 G80 M3 AWD
Join Date: Sep 2013
Location: Atlanta, GA

iTrader: (0)

Quote:
Originally Posted by enemigo13 View Post
how much you think you will loose max hp (not midrange but max hp) installing stock dp on? probably 10hp, but not 20-30whp like downpipe sellers declare.
With stock DP I'll be back to JB4 Map 1 and that's a difference of 4-5psi which is a lot. There's a night & day difference between JB4 Map 1 and the way my car currently runs on Map 5. Not sure how much hp difference as I've never gone to the dyno but my butt dyno says torque difference is 100lb-ft!

Quote:
Originally Posted by bmwchue View Post
Maybe a catted downpipe bit its pricey
I'm worried a catted dp may not pass emissions and I've yet to find a catted dp that guarantees no CEL or emissions issues.

Quote:
Originally Posted by bradsm87 View Post
Keep the catless downpipe, ditch the JB4 and get a proper flash tune. MHD or Bootmod3.
But that's not going to solve my emissions or smell issues.

Quote:
Originally Posted by wibbles View Post
300 Cell Sports Cat may be the answer.
Any specific one you tried and does not trigger a CEL?

Quote:
Originally Posted by Whistlefist View Post
How exactly will that help him with emissions checks or the smell?
Exactly
__________________

2022 G80 M3 Comp M xDrive
Appreciate 0
      03-23-2018, 11:28 AM   #8
M3AWD
Lieutenant Colonel
M3AWD's Avatar
United_States
3178
Rep
1,902
Posts

Drives: 2022 G80 M3 AWD
Join Date: Sep 2013
Location: Atlanta, GA

iTrader: (0)

I'm thinking someone must have good experience with an aftermarket hi-flow catted dp or even another combination of mods on stock dp??

How about with more serious mods... Has anyone gone with aftermarket intercooler and seen measureable benefit on stock dp? How about fuel system upgrades etc? Or even aftermarket turbos?

That's not where I was trying to go with this thread but it appears focus for modding an F30 N55 during the past 2 years is on tunes instead of piggy-backs, but from my research those tunes don't add much more value (power) with the restriction of a stock dp.
__________________

2022 G80 M3 Comp M xDrive
Appreciate 0
      03-23-2018, 12:18 PM   #9
alohasurftoad
Brigadier General
3008
Rep
4,259
Posts

Drives: 440i gran coupe w/mppsk
Join Date: Apr 2015
Location: hawaii

iTrader: (0)

unfortunately, as you've already noted, the stock downpipe is the bottleneck. if you go back to stock, no sense in going too crazy in front of it. an aftermarket FMIC is something missing and would be a good addition to your setup. imo wagner's competition evo I would be appropriate since it is lightweight and has a tube fin core but there are cheaper bar-plate stepped cores that would do almost as well if you didn't want to spend that much.

for high flow catted downpipes look into fabspeed's sport cat with HJS 300cell cores. it's not cheap, though.

EDIT: a GFB diverter valve is also another thing to add

Last edited by alohasurftoad; 03-24-2018 at 01:06 AM..
Appreciate 0
      03-23-2018, 01:21 PM   #10
ceedawg
Major
ceedawg's Avatar
466
Rep
1,348
Posts

Drives: 2k15 335i xdrive MSport 6spd
Join Date: Dec 2017
Location: Big City

iTrader: (0)

Quote:
Originally Posted by alohasurftoad View Post
unfortunately, as you've already noted, the stock downpipe is the bottleneck. if you go back to stock, no sense in going to crazy in front of it. an aftermarket FMIC is something missing and would be a good addition to your setup. imo wagner's competition evo I would be appropriate since it is lightweight and has a tube fin core but there are cheaper bar-plate stepped cores that would do almost as well if you didn't want to spend that much.

for high flow catted downpipes look into fabspeed's sport cat with HJS 300cell cores. it's not cheap, though.

EDIT: a GFB diverter valve is also another thing to add
wagner comp 2 is bar and fin.
__________________
2k15 335i Msport xdrive 6spd
Wagner Comp2 FMIC,FTP CP,stock exhaust. Fabspeed Sport catted DP, KW V2 coil overs,FBO BM3 Stg 2
Appreciate 0
      03-23-2018, 01:24 PM   #11
ceedawg
Major
ceedawg's Avatar
466
Rep
1,348
Posts

Drives: 2k15 335i xdrive MSport 6spd
Join Date: Dec 2017
Location: Big City

iTrader: (0)

Quote:
Originally Posted by M-SP0RT View Post
I'm thinking someone must have good experience with an aftermarket hi-flow catted dp or even another combination of mods on stock dp??

How about with more serious mods... Has anyone gone with aftermarket intercooler and seen measureable benefit on stock dp? How about fuel system upgrades etc? Or even aftermarket turbos?

That's not where I was trying to go with this thread but it appears focus for modding an F30 N55 during the past 2 years is on tunes instead of piggy-backs, but from my research those tunes don't add much more value (power) with the restriction of a stock dp.
I’m going stock dp,Wagner comp 2 or CTS fmic, AA flash tune stag 1 so I am anxious to see without raising boost how much difference a cat less dp will make. Key is without raising boost.
__________________
2k15 335i Msport xdrive 6spd
Wagner Comp2 FMIC,FTP CP,stock exhaust. Fabspeed Sport catted DP, KW V2 coil overs,FBO BM3 Stg 2
Appreciate 0
      03-23-2018, 04:26 PM   #12
BMW DIY Guy
Colonel
BMW DIY Guy's Avatar
United_States
3002
Rep
2,989
Posts

Drives: 2019 M2 Competition
Join Date: Jan 2017
Location: Maple Valley WA

iTrader: (1)

Garage List
2024 BMW M2  [9.75]
2017 BMW X1  [10.00]
2001 BMW X5  [10.00]
Quote:
Originally Posted by alohasurftoad View Post
unfortunately, as you've already noted, the stock downpipe is the bottleneck. if you go back to stock, no sense in going to crazy in front of it. an aftermarket FMIC is something missing and would be a good addition to your setup. imo wagner's competition evo I would be appropriate since it is lightweight and has a tube fin core but there are cheaper bar-plate stepped cores that would do almost as well if you didn't want to spend that much.

for high flow catted downpipes look into fabspeed's sport cat with HJS 300cell cores. it's not cheap, though.

EDIT: a GFB diverter valve is also another thing to add
AA has a high flow catted DP just on the horizon, and I will be transitioning from my stock cat to that as soon as they can ship it. I also am doing the DV+ actually this sunday and will post the DIY on the forums.
__________________
Check out my BMW DIY Channel on YouTube! E, F and G series projects from Active Autowerke, Bimmertech, Kies Motorsports, AvinUSA, Karbonius Composites and more!
** YouTube BMW DIY Guy **
'Nimona' G87 M2 Build Thread
'Lillith' F87 M2 Competition Build Thread
Appreciate 0
      03-23-2018, 06:54 PM   #13
louielouie
Major
United_States
532
Rep
1,033
Posts

Drives: '18 F80
Join Date: Jan 2016
Location: Los Angeles

iTrader: (13)

Quote:
Originally Posted by alohasurftoad View Post
unfortunately, as you've already noted, the stock downpipe is the bottleneck. if you go back to stock, no sense in going to crazy in front of it. an aftermarket FMIC is something missing and would be a good addition to your setup. imo wagner's competition evo I would be appropriate since it is lightweight and has a tube fin core but there are cheaper bar-plate stepped cores that would do almost as well if you didn't want to spend that much.

for high flow catted downpipes look into fabspeed's sport cat with HJS 300cell cores. it's not cheap, though.

EDIT: a GFB diverter valve is also another thing to add
I've been looking for a catted DP as well.

+1 Fabspeed. HJS cat is quoted 93% as much flow as catless.
Appreciate 0
      03-23-2018, 09:28 PM   #14
ceedawg
Major
ceedawg's Avatar
466
Rep
1,348
Posts

Drives: 2k15 335i xdrive MSport 6spd
Join Date: Dec 2017
Location: Big City

iTrader: (0)

Quote:
Originally Posted by raichean View Post
AA has a high flow catted DP just on the horizon, and I will be transitioning from my stock cat to that as soon as they can ship it. I also am doing the DV+ actually this sunday and will post the DIY on the forums.
Hopefully the cost won’t be anywhere near crazy like fabspeed.
__________________
2k15 335i Msport xdrive 6spd
Wagner Comp2 FMIC,FTP CP,stock exhaust. Fabspeed Sport catted DP, KW V2 coil overs,FBO BM3 Stg 2
Appreciate 0
Post 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 11:17 AM.




f30post
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