E90Post
 


 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > NA Engine (non-turbo) / Drivetrain / Exhaust Modifications > how many hp does it gain by deleting two cats?



Reply
 
Thread Tools Search this Thread
      01-22-2011, 12:53 AM   #1
FVM3
Major General
 
FVM3's Avatar
 
Drives: e92 m3, f30 328i
Join Date: Sep 2010
Location: Los Angeles

Posts: 5,734
iTrader: (2)

how many hp does it gain by deleting two cats?

i got a friend with an e90 328i running straight pipe and that setup still doesnt satisfy him so he deleted two cats. How many hp does it gain by deleting the cats and straight pipe? He asked me this question but i totally have no idea
FVM3 is offline  
0
Reply With Quote
      01-22-2011, 01:13 AM   #2
TommyK
Brigadier General
 
TommyK's Avatar
 
Drives: E90 335i LCI
Join Date: Aug 2008
Location: Orange County, CA

Posts: 3,326
iTrader: (9)

Garage List
2009 BMW 335i LCI  [0.00]
2006 E90 330i  [0.00]
Send a message via AIM to TommyK
This is just ball park but maybe 5hp plus the extra power given by taking that extra 65 pounds off the car for removing all that extra weight will help the most
TommyK is offline   United_States
0
Reply With Quote
      01-22-2011, 02:06 AM   #3
SuperAwesome
^K33pNitG@ngSt@^
 
SuperAwesome's Avatar
 
Drives: e92
Join Date: Jan 2011
Location: East Coast

Posts: 102
iTrader: (0)

-10
__________________
GOT GERMAN?
SuperAwesome is offline   Yugoslavia
0
Reply With Quote
      01-22-2011, 04:31 AM   #4
FVM3
Major General
 
FVM3's Avatar
 
Drives: e92 m3, f30 328i
Join Date: Sep 2010
Location: Los Angeles

Posts: 5,734
iTrader: (2)

He told me that after deleting the cats, theres less drone from the exhaust...thats kinda weird.
FVM3 is offline  
0
Reply With Quote
      01-22-2011, 04:37 AM   #5
c_jeong89
Banned
 
Drives: E90 TiAg
Join Date: Feb 2009
Location: Irvine/Bay Area

Posts: 2,097
iTrader: (16)

i deleted my secondary cats with my bmw perf exhaust. I can hear more exhaust noise but I never had any drone before and still dont.
c_jeong89 is offline   United_States
0
Reply With Quote
      01-22-2011, 05:40 PM   #6
sandman0615
obsessed....
 
sandman0615's Avatar
 
Drives: e90 325xi 6sp
Join Date: Sep 2009
Location: ffld, ct

Posts: 523
iTrader: (2)

i may be mistaken and correct me if i'm wrong but i remember reading the primary cat is really restrictive and a primary cat delete is a solid 10+ hp (not ebay 10+hp but legit)
__________________
|6SP|BILSTEIN/H&R SPORTS|INJEN CAI|BMS PBX|DEPO P90 6000K|x244 LED AE|BLACKLINES|20% TINT|MATTE KIDNEYS|BLACKOUT EMBLEMS|10" BAZOOKA|

||DIY: DEPO P90||
RIP E46 330xi
sandman0615 is offline  
0
Reply With Quote
      01-22-2011, 06:21 PM   #7
LaLakers91tc
Lieutenant Colonel
 
LaLakers91tc's Avatar
 
Drives: BSM E92 335i 6MT
Join Date: Feb 2008
Location: Lawrenceville NJ

Posts: 1,860
iTrader: (5)

I would think you need a tune to truly utilize the reduced backpressure and faster airflow through the engine properly
I deleted my secondaries with the Eisenmann SR midpipes and I honestly can't tell much of a difference other than the wonderful sound.
__________________
Current 07 BSM E92 335i

Previous SGM E90 330i (R.I.P.)
LaLakers91tc is offline   United_States
0
Reply With Quote
      01-22-2011, 06:41 PM   #8
e90pilot
Freight Dawg
 
e90pilot's Avatar
 
Drives: E90 325i
Join Date: Jul 2005
Location: Oakland, CA

Posts: 2,105
iTrader: (3)

There is a racing with a 328 team that kept the stock headers but just deleted the primary cats. They reported a gain of 15 hp to the wheels. Of course this is all dependent of the dyno used and the testing conditions.
__________________
--Marcelo
'06 Arctic Metallic 325i | Sport Package | 6MT | Dinan Stage III suspension | Dinan exhaust | 330i manifold swap! Click here! | Active Autowerke tune | 135i Brake Calipers | Deiselboost caliper brackets | E46 M3 front rotors
e90pilot is offline   United_States
0
Reply With Quote
      01-23-2011, 07:02 PM   #9
Me_Hi
Major
 
Me_Hi's Avatar
 
Drives: *
Join Date: Jun 2009
Location: *

Posts: 1,490
iTrader: (13)

Which ones (cats) are mandatory for passing emissions?
__________________
Me_Hi is offline   No_Country
0
Reply With Quote
      01-23-2011, 10:42 PM   #10
SuperAwesome
^K33pNitG@ngSt@^
 
SuperAwesome's Avatar
 
Drives: e92
Join Date: Jan 2011
Location: East Coast

Posts: 102
iTrader: (0)

Yes your primary cats are ..
__________________
GOT GERMAN?
SuperAwesome is offline   Yugoslavia
0
Reply With Quote
      01-24-2011, 12:07 AM   #11
AlpineSwift
Colonel
 
AlpineSwift's Avatar
 
Drives: 2008 335Xi Coupé
Join Date: Feb 2010
Location: Castle Rock, CO

Posts: 2,109
iTrader: (3)

I've said it before and I'll say it again:
My thought has always been that if you delete the primaries, run 02 sims, and keep the secondaries you should be able to pass emissions. Unless you're in cali, then you're fraked.
__________________
E92 '08 335Xi 6AT - Cobb AP V2, ar design DP's, Race Cats in the mids, Stock cans, VRSF CP w/Tial BOV, VRSF 7" FMIC, BMS DCI, BMS Cowl, H&R Coilovers, Renn Motorsport RS-51's, Alpina TCU Flash, Turner Boost Gauge, Fully Coded.
Best 1/4mi: 13.201 @ 106.93 / 2.0 60' / DA=9300ft

Tanya: The Build Thread
AlpineSwift is offline   United_States
0
Reply With Quote
      01-24-2011, 12:13 AM   #12
3002 tii
Major General
 
3002 tii's Avatar
 
Drives: flat out
Join Date: Apr 2008
Location: NNJ

Posts: 8,282
iTrader: (46)

Garage List
Quote:
Originally Posted by e90pilot View Post
There is a racing with a 328 team that kept the stock headers but just deleted the primary cats. They reported a gain of 15 hp to the wheels. Of course this is all dependent of the dyno used and the testing conditions.
how would you retain stock headers while deleting primary cats?
__________________

Recaro | Volk | AST | Vorshlag | Quaife | Stoptech | Active Autowerke | BMW Performance

Click here for my track videos
3002 tii is offline   United_States
0
Reply With Quote
      01-24-2011, 12:29 AM   #13
AlpineSwift
Colonel
 
AlpineSwift's Avatar
 
Drives: 2008 335Xi Coupé
Join Date: Feb 2010
Location: Castle Rock, CO

Posts: 2,109
iTrader: (3)

Quote:
Originally Posted by Dubbedown View Post
how would you retain stock headers while deleting primary cats?
Me thinks there was some serious fabrication involved. Maybe Gavin can shed some light on what the stock headers look like and how much work would be involved in removing the primaries.
__________________
E92 '08 335Xi 6AT - Cobb AP V2, ar design DP's, Race Cats in the mids, Stock cans, VRSF CP w/Tial BOV, VRSF 7" FMIC, BMS DCI, BMS Cowl, H&R Coilovers, Renn Motorsport RS-51's, Alpina TCU Flash, Turner Boost Gauge, Fully Coded.
Best 1/4mi: 13.201 @ 106.93 / 2.0 60' / DA=9300ft

Tanya: The Build Thread
AlpineSwift is offline   United_States
0
Reply With Quote
      01-24-2011, 04:10 AM   #14
e90pilot
Freight Dawg
 
e90pilot's Avatar
 
Drives: E90 325i
Join Date: Jul 2005
Location: Oakland, CA

Posts: 2,105
iTrader: (3)

Quote:
Originally Posted by Dubbedown View Post
how would you retain stock headers while deleting primary cats?
Cut the cats, weld a pipe where the cats used to be. Thats what a racing team did.
__________________
--Marcelo
'06 Arctic Metallic 325i | Sport Package | 6MT | Dinan Stage III suspension | Dinan exhaust | 330i manifold swap! Click here! | Active Autowerke tune | 135i Brake Calipers | Deiselboost caliper brackets | E46 M3 front rotors
e90pilot is offline   United_States
0
Reply With Quote
      01-24-2011, 10:41 AM   #15
3002 tii
Major General
 
3002 tii's Avatar
 
Drives: flat out
Join Date: Apr 2008
Location: NNJ

Posts: 8,282
iTrader: (46)

Garage List
Quote:
Originally Posted by e90pilot View Post
Cut the cats, weld a pipe where the cats used to be. Thats what a racing team did.
That works but not something most shops or DIY guys would want to do (or are capable of doing in a clean manner). I really wish someone would come up with quality N52 headers with perfect fitment, no hack jobs.
__________________

Recaro | Volk | AST | Vorshlag | Quaife | Stoptech | Active Autowerke | BMW Performance

Click here for my track videos
3002 tii is offline   United_States
0
Reply With Quote
      01-24-2011, 10:58 AM   #16
kamek
Brigadier General
 
Drives: 328xi 6MT
Join Date: Mar 2008
Location: Queens, NY

Posts: 3,179
iTrader: (4)

Garage List
2008 BMW 328xi  [4.10]
Send a message via AIM to kamek
Quote:
Originally Posted by Dubbedown View Post
That works but not something most shops or DIY guys would want to do (or are capable of doing in a clean manner). I really wish someone would come up with quality N52 headers with perfect fitment, no hack jobs.
Def will pick up headers if that ever happens...
__________________

E92 328xi | KW | AA | LUX | OEM 359M | BMW Performance Exhaust
kamek is offline   United_States
0
Reply With Quote
      01-24-2011, 11:13 AM   #17
3002 tii
Major General
 
3002 tii's Avatar
 
Drives: flat out
Join Date: Apr 2008
Location: NNJ

Posts: 8,282
iTrader: (46)

Garage List
Quote:
Originally Posted by kamek View Post
Def will pick up headers if that ever happens...

I know Supersprint offers one but

1) super expensive
2) i don't think it's plug n play to oem secondary cats (they encourage u to buy their high flow secondaries for a perfect fitment)
3) still no definitive answer as to how to get around CEL - yes i know what "should" work but i've yet to see anyone buy the headers and confirm that it indeed works.
__________________

Recaro | Volk | AST | Vorshlag | Quaife | Stoptech | Active Autowerke | BMW Performance

Click here for my track videos
3002 tii is offline   United_States
0
Reply With Quote
      01-24-2011, 11:17 AM   #18
jfisher160
First Lieutenant
 
Drives: 2013 320i Sedan
Join Date: Jun 2010
Location: Thousand Oaks, CA

Posts: 332
iTrader: (3)

If your going to delete the primary cats, I would just get new headers and do it right. Why are you going to mess with the welding to the old headers. If you want as much HP as possible then just add new headers to the car. I have been in Cravens car with aftermarket headers and not cats and it's pretty sweet.
__________________
New - 2013 - 320i - 15% Tint - Future Mods ( BMS Tune, Suspension, Wheels, Exhaust)

Sold - 2007 328i (3-Stage Manifold - BMW Perf Intake w/Scoops - Powerbox - Magnaflow Exhaust - MMW Headers - KW Street Comfort - VMR 701s 19' w/M3 offset - BMW Strut Brace - 330I Brake Conversation - 5% Tint All Around - 8K HID Fog Lights -Angel Eyes)
jfisher160 is offline  
0
Reply With Quote
      01-24-2011, 01:07 PM   #19
AlpineSwift
Colonel
 
AlpineSwift's Avatar
 
Drives: 2008 335Xi Coupé
Join Date: Feb 2010
Location: Castle Rock, CO

Posts: 2,109
iTrader: (3)

Quote:
Originally Posted by jfisher160 View Post
If your going to delete the primary cats, I would just get new headers and do it right. Why are you going to mess with the welding to the old headers. If you want as much HP as possible then just add new headers to the car. I have been in Cravens car with aftermarket headers and not cats and it's pretty sweet.
Be nice if he ever manages to get a good sound clip that doesn't sound like ass.
__________________
E92 '08 335Xi 6AT - Cobb AP V2, ar design DP's, Race Cats in the mids, Stock cans, VRSF CP w/Tial BOV, VRSF 7" FMIC, BMS DCI, BMS Cowl, H&R Coilovers, Renn Motorsport RS-51's, Alpina TCU Flash, Turner Boost Gauge, Fully Coded.
Best 1/4mi: 13.201 @ 106.93 / 2.0 60' / DA=9300ft

Tanya: The Build Thread
AlpineSwift is offline   United_States
0
Reply With Quote
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
Forum Jump


All times are GMT -5. The time now is 04:56 PM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
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