Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 7 Series / 8 Series > 7 Series - F01 / F02 (2009 - current)

7 Series - F01 / F02 (2009 - current)
The new re-designed 7 series F01 / F02 leads off the BMW Fxx chassis code!

Reply
 
Thread Tools Display Modes
  #1  
Old 07-29-2011, 06:51 PM
eclou eclou is offline
Registered User
Location: Houston
 
Join Date: Jul 2011
Posts: 28
Mein Auto: 911 turbo
The $0.50 exhaust mod

Decided to do some early work on the F02 today and started with hardwiring the V1 detector. Things went very simply thanks to the writeup by swisstype here. Just for kicks I put the car up on my 2 post lift and checked out the underbelly.



I played around with the exhaust solenoids and they look to be vacuum operated with a spring-closed by default design.



The actuator arms move pretty smoothly so I decided to try to clamp them open:

Clamp - I used a small hose clamp the size of your pinky:



Use a prybar or something similar to wedge the exhaust flap to the "open" position. As it sits open then put the clamp around the actuator arm at the elbow, holding it open. Here are pics of the clamps applied to the arms-

Passenger side:



Driver side:



Done:




Good news - this is cheap and easy to do - maybe 10 minutes, and reversible in 5 minutes.

Bad news - the amount of sound transmission increase is minimal. There is a slightly deeper tone at idle, but really marginal. I want/need more.



The exhaust runs from the manifolds up front back to two small resonator/cats then a merged resonator before hitting the mufflers. This run from just behind the manifolds is clamped in the front and welded all the way back. There are no oxygen sensors involved or visible in the entire section so it should be able to be swapped for straight or X- style middle section and then some mufflers in back.
__________________
2012 750iL Msport
2008 Cayenne turbo - gone
2007 997 turbo
2000 Boxster S track car
1997 993 turbo
1986 944 turbo LS6 track car

Reply With Quote
Advertisement
  #2  
Old 07-29-2011, 08:28 PM
ant369 ant369 is offline
Registered User
Location: NJ
 
Join Date: May 2008
Posts: 69
Mein Auto: 330ci 335d
Nice garage!
Reply With Quote
  #3  
Old 07-30-2011, 12:21 PM
ruey220 ruey220 is offline
Officially Welcomed to the 'Fest
Location: SF
 
Join Date: Jun 2010
Posts: 150
Mein Auto: Benz
back when BMW introduced this type of exhaust on the E36 and started putting them on other models I remember our tinkering group played with those flaps and realized it is very minimal difference when it comes to sound. BMW used this for its vanos technology with tuning exhaust sound waves etc from low RPM to high RPM requirements in the backpressure effect. as far as sound is concerned, i consider it like putting an extra speaker with the same amount of volume from the same source, if you notice turning on a second speaker on your computer will give you stereo effect, but the decibel level does not double. i think the flap is not about sound but rather for some performance effect.

keeping it open without changing the source (internal muffler design) will probably harm your performance than do good.
Reply With Quote
  #4  
Old 07-30-2011, 03:37 PM
eclou eclou is offline
Registered User
Location: Houston
 
Join Date: Jul 2011
Posts: 28
Mein Auto: 911 turbo
Quote:
Originally Posted by ruey220 View Post
keeping it open without changing the source (internal muffler design) will probably harm your performance than do good.
any sort of resonance tuning would be relevant somewhere within the first 3-4' of the exhaust port. This far back there should be little to no scavenging effect.
__________________
2012 750iL Msport
2008 Cayenne turbo - gone
2007 997 turbo
2000 Boxster S track car
1997 993 turbo
1986 944 turbo LS6 track car

Reply With Quote
  #5  
Old 08-05-2011, 08:26 AM
ruey220 ruey220 is offline
Officially Welcomed to the 'Fest
Location: SF
 
Join Date: Jun 2010
Posts: 150
Mein Auto: Benz
i'm beggining to wonder about this flap, when is it supposed to be closed/open. I realized when I was testing my exhaust, the flap was open while the car was in idle, then when the mechanic shut off the engine it closed the valve.

Is that the way all 750's are or does the B7 have a modified flap that stays open when the car is running? I did research and came up with another Alpina video for the flap and it does the same thing.


Reply With Quote
  #6  
Old 08-22-2011, 03:22 AM
Amalan Amalan is offline
Registered User
Location: Cincinnati
 
Join Date: Jul 2007
Posts: 56
Mein Auto: 745Li
Quote:
Originally Posted by eclou View Post
Decided to do some early work on the F02 today and started with hardwiring the V1 detector. Things went very simply thanks to the writeup by swisstype
srsly a v1? not saying that its not a great detector... just not for our cars. we have infrared windshields that cut like 70% of the detectors performance. so unless you hardwired it into the grill, id suggest taking a look into picking up a 9500ci, sti-r+ or whistler 3600
Reply With Quote
  #7  
Old 08-22-2011, 03:35 AM
Amalan Amalan is offline
Registered User
Location: Cincinnati
 
Join Date: Jul 2007
Posts: 56
Mein Auto: 745Li
Quote:
Originally Posted by eclou View Post
Decided to do some early work on the F02 today and started with hardwiring the V1 detector. Things went very simply thanks to the writeup by swisstype
srsly a v1? not saying that its not a great detector... just not for our cars. we have infrared windshields that cut like 70% of the detectors performance. so unless you hardwired it into the grill, id suggest taking a look into picking up a 9500ci, sti-r+ or whistler 3600
Reply With Quote
  #8  
Old 08-22-2011, 08:54 AM
MOPAULY's Avatar
MOPAULY MOPAULY is offline
Officially Welcomed to the 'Fest
Location: Spring Mount, PA
 
Join Date: Sep 2010
Posts: 1,639
Mein Auto: Many things
If you locate the vacuum solenoid the lines connect too, you can bypass it to hold the valve open all the time the car is running, and it will look better than a .50 cheap hose clamp
__________________
Reply With Quote
  #9  
Old 04-30-2012, 07:19 AM
Quicksilver1010 Quicksilver1010 is offline
Registered User
Location: New Jersey
 
Join Date: Nov 2011
Posts: 77
Mein Auto: M6 Vert
has anyone else done this mod? The exhuast does sound a little weak on our cars.
Reply With Quote
  #10  
Old 04-30-2012, 02:18 PM
Gundo Gundo is offline
Registered User
Location: Connecticut
 
Join Date: May 2011
Posts: 47
Mein Auto: '11 750i
I'm pretty sure the engine computer map is optimized for different levels of back pressure. There is no question that at certain points, an exhaust with less back pressure will yield less hp. Now, if this is just for fun and an attempt for more noise, I'm all for it!
Reply With Quote
  #11  
Old 04-30-2012, 03:35 PM
grigia grigia is offline
Registered User
Location: Suburbs Chicago, USA
 
Join Date: Oct 2007
Posts: 31
Mein Auto: 2011 750il hybrid
Really Valentine One isn't good for the 750? I was about to install...
Reply With Quote
Reply

Bookmarks


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 7 Series / 8 Series > 7 Series - F01 / F02 (2009 - current)
Today's Posts Search
Thread Tools
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 On



Forum Jump


All times are GMT -7. The time now is 07:45 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms