BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Engine, Transmission, Exhaust, Drivetrain, ECU Software Modifications
 
ESS Tuning
Post Reply
 
Thread Tools Search this Thread
      07-27-2009, 04:23 PM   #1
Mr.Metak2you
Brigadier General
Mr.Metak2you's Avatar
121
Rep
4,757
Posts

 
Drives: LEXUS LS(DailyDriver)
Join Date: Nov 2007
Location: Astral Projecting: ∞ 23.516 -122 02.625 0242.101 ĕv'rē-hwr'

iTrader: (15)

Garage List
OEM exhaust design...

Now that I have my stock exhaust off the car I could get a closer look at it. Seems to me the bends are 'kinked' bad (no mandrel bending). Also for those who have switched out their exhaust for an aftermarket system, do you think the lack of heat shields(found on the stock unit) that are not on most aftermarket exhausts, have any adverse effect? What were the heat shields shielding?

Name:  OEM.JPG
Views: 940
Size:  53.7 KB
__________________
Appreciate 0
      07-27-2009, 04:34 PM   #2
Lemans_Blue_M
Automotive Industry Insider
Lemans_Blue_M's Avatar
United_States
19
Rep
1,948
Posts

 
Drives: Lemans Blue M3
Join Date: Aug 2007
Location: Texas

iTrader: (0)

Quote:
Originally Posted by ///Metak View Post
Now that I have my stock exhaust off the car I could get a closer look at it. Seems to me the bends are 'kinked' bad (no mandrel bending). Also for those who have switched out their exhaust for an aftermarket system, do you think the lack of heat shields(found on the stock unit) that are not on most aftermarket exhausts, have any adverse effect? What were the heat shields shielding?

Attachment 290395
That helps block radiated exhaust heat from rasing the temperature of the diff. (and the gear oil inside the casing)
__________________
The best is yet to come...
Appreciate 0
      07-27-2009, 04:38 PM   #3
Lemans_Blue_M
Automotive Industry Insider
Lemans_Blue_M's Avatar
United_States
19
Rep
1,948
Posts

 
Drives: Lemans Blue M3
Join Date: Aug 2007
Location: Texas

iTrader: (0)

Quote:
Originally Posted by ///Metak View Post
Now that I have my stock exhaust off the car I could get a closer look at it. Seems to me the bends are 'kinked' bad (no mandrel bending). Also for those who have switched out their exhaust for an aftermarket system, do you think the lack of heat shields(found on the stock unit) that are not on most aftermarket exhausts, have any adverse effect? What were the heat shields shielding?

Attachment 290395
Yes, the OE exhaust system is not mandral bent pipe, and that does ultimately effect the flow and back pressure.
__________________
The best is yet to come...
Appreciate 0
      07-27-2009, 04:47 PM   #4
Mr.Metak2you
Brigadier General
Mr.Metak2you's Avatar
121
Rep
4,757
Posts

 
Drives: LEXUS LS(DailyDriver)
Join Date: Nov 2007
Location: Astral Projecting: ∞ 23.516 -122 02.625 0242.101 ĕv'rē-hwr'

iTrader: (15)

Garage List
Quote:
Originally Posted by Lemans_Blue_M View Post
That helps block radiated exhaust heat from rasing the temperature of the diff. (and the gear oil inside the casing)
I figured it was for the diff. because it right by those particular bends, but how much of an issue is heat going to be with the aftermarket systems? I'm not losing sleep or anything, just curious.

What I find strange is the 1st, 2nd and 4th bends seem almost as if they were mandrel bent(a lot smoother), but that 3rd bend is bad, almost as if it were by design, dunno?
__________________
Appreciate 0
      07-27-2009, 05:04 PM   #5
askiles
Major
askiles's Avatar
23
Rep
1,164
Posts

 
Drives: 2008 M3 Sedan - Alpine White
Join Date: Apr 2009
Location: Phoenix, AZ

iTrader: (2)

I am not sure how the pipe is bent, but it is triangular in places so that it fits better through the curves. It is really weird, but I am sure BMW did it that way on purpose.

-Andy
__________________
2008 M3 Sedan- Alpine White
Appreciate 0
      07-27-2009, 05:05 PM   #6
Ilia@IND
BimmerPost Supporting Vendor
Ilia@IND's Avatar
106
Rep
2,205
Posts


 
Drives: F82 M4
Join Date: Oct 2006
Location: Chicago

iTrader: (3)

The heat shields are placed near the CV boots on the E92 M3.

We've found that not running heat shields will result in premature wear of the CV boots, and will cause CV failure in some situations involving especially hard driving. We install heat shields on all Eisenmann connecting pipes for that reason.
__________________
Appreciate 0
      07-27-2009, 05:09 PM   #7
Mr.Metak2you
Brigadier General
Mr.Metak2you's Avatar
121
Rep
4,757
Posts

 
Drives: LEXUS LS(DailyDriver)
Join Date: Nov 2007
Location: Astral Projecting: ∞ 23.516 -122 02.625 0242.101 ĕv'rē-hwr'

iTrader: (15)

Garage List
Quote:
Originally Posted by Ilia@IND View Post
The heat shields are placed near the CV boots on the E92 M3.

We've found that not running heat shields will result in premature wear of the CV boots, and will cause CV failure in some situations involving especially hard driving. We install heat shields on all Eisenmann connecting pipes for that reason.
Hmmm, I might have a muffler shop do that for me on my Dinan system. Thanks!
__________________
Appreciate 0
      07-27-2009, 05:15 PM   #8
Lemans_Blue_M
Automotive Industry Insider
Lemans_Blue_M's Avatar
United_States
19
Rep
1,948
Posts

 
Drives: Lemans Blue M3
Join Date: Aug 2007
Location: Texas

iTrader: (0)

Quote:
Originally Posted by ///Metak View Post
I figured it was for the diff. because it right by those particular bends, but how much of an issue is heat going to be with the aftermarket systems? I'm not losing sleep or anything, just curious.
OE exhaust applications typically go overboard on such things like heat shielding to avoid unintended consequences. (even if the chances of any real impact are remote)

The engineering group at Arvin Meritor, (M3 OE exhaust supplier) probably suggested this to BMW during their R&D.

This precaution was implemented due to the close proximity of the dual exhaust pipes as they 'snake' around the differential casing.

I can't see that it would make much difference, but I guess it wouldn't hurt to re-use them. (or fabricate something similar)

I would only do this if you are truly concerned about the additional heat transfer from your unshielded aftermarket exhaust.

No idea how much difference it really makes...
__________________
The best is yet to come...
Appreciate 0
      07-27-2009, 05:25 PM   #9
Mr.Metak2you
Brigadier General
Mr.Metak2you's Avatar
121
Rep
4,757
Posts

 
Drives: LEXUS LS(DailyDriver)
Join Date: Nov 2007
Location: Astral Projecting: ∞ 23.516 -122 02.625 0242.101 ĕv'rē-hwr'

iTrader: (15)

Garage List
Quote:
Originally Posted by Lemans_Blue_M View Post
OE exhaust applications typically go overboard on such things like heat shielding to avoid unintended consequences. (even if the chances of any real impact are remote)

The engineering group at Arvin Meritor, (M3 OE exhaust supplier) probably suggested this to BMW during their R&D.

This precaution was implemented due to the close proximity of the dual exhaust pipes as they 'snake' around the differential casing.

I can't see that it would make much difference, but I guess it wouldn't hurt to re-use them. (or fabricate something similar)

I would only do this if you are truly concerned about the additional heat transfer from your unshielded aftermarket exhaust.

No idea how much difference it really makes...
I think the diff. would withstand heat better than the rubber parts of the CV like Ilia@IND suggested. Worth looking into IMO.
__________________
Appreciate 0
      07-27-2009, 05:39 PM   #10
Lemans_Blue_M
Automotive Industry Insider
Lemans_Blue_M's Avatar
United_States
19
Rep
1,948
Posts

 
Drives: Lemans Blue M3
Join Date: Aug 2007
Location: Texas

iTrader: (0)

Quote:
Originally Posted by ///Metak View Post
I think the diff. would withstand heat better than the rubber parts of the CV like Ilia@IND suggested. Worth looking into IMO.
Yes, CV joints would certainly be more susceptible to the heat.

That's one of those unintended consequences I suppose.

Hmm...

I wonder how many other exhaust manufacturers, retailers, and install shops have figured this out...
__________________
The best is yet to come...
Appreciate 0
      07-27-2009, 05:40 PM   #11
Ilia@IND
BimmerPost Supporting Vendor
Ilia@IND's Avatar
106
Rep
2,205
Posts


 
Drives: F82 M4
Join Date: Oct 2006
Location: Chicago

iTrader: (3)

I have seen the rubber boots melt because of the heat, and lose all of the grease packed into the CV joints, but this happened with a very large diameter race exhaust, during an endurance racing event.
__________________
Appreciate 0
      07-27-2009, 05:50 PM   #12
Lemans_Blue_M
Automotive Industry Insider
Lemans_Blue_M's Avatar
United_States
19
Rep
1,948
Posts

 
Drives: Lemans Blue M3
Join Date: Aug 2007
Location: Texas

iTrader: (0)

Quote:
Originally Posted by Ilia@IND View Post
I have seen the rubber boots melt because of the heat, and lose all of the grease packed into the CV joints, but this happened with a very large diameter race exhaust, during an endurance racing event.
Question...

Did IND figure this out over time...or did Eisenmann alert you to this before you sold their product?

Curious to see who discovered this issue, and when was it identified as a potential problem.
__________________
The best is yet to come...
Appreciate 0
      07-27-2009, 05:55 PM   #13
PunjabiM3
Lieutenant Colonel
PunjabiM3's Avatar
India
35
Rep
1,830
Posts

 
Drives: R8 5.2 6MT
Join Date: Mar 2008
Location: Oro Valley, AZ

iTrader: (1)

Quote:
Originally Posted by Lemans_Blue_M View Post
Question...

Did IND figure this out over time...or did Eisenmann alert you to this before you sold their product?

Curious to see who discovered this issue, and when was it identified as a potential problem.
I'm sure that's classified info lol...
__________________
2012 Audi R8 V10, 6MT, Suzuka Gray, Capristo X-Pipe, Klassen M52R, GMG springs, R8 GT tails, Satin Black badges
2012 Audi A6 3.0T Prestige, Moonlight Blue
2015 BMW X5 35d, Mineral White
Previous: 11 e82 1M, Several 911's & M3's
Appreciate 0
      07-27-2009, 05:58 PM   #14
Lemans_Blue_M
Automotive Industry Insider
Lemans_Blue_M's Avatar
United_States
19
Rep
1,948
Posts

 
Drives: Lemans Blue M3
Join Date: Aug 2007
Location: Texas

iTrader: (0)

Quote:
Originally Posted by PunjabiM3 View Post
I'm sure that's classified info lol...
It's a fair question to ask a reputable vendor on this site.

Besides, I know classified...and that type of thing ain't classified brother.
__________________
The best is yet to come...
Appreciate 0
      07-27-2009, 06:09 PM   #15
Mr.Metak2you
Brigadier General
Mr.Metak2you's Avatar
121
Rep
4,757
Posts

 
Drives: LEXUS LS(DailyDriver)
Join Date: Nov 2007
Location: Astral Projecting: ∞ 23.516 -122 02.625 0242.101 ĕv'rē-hwr'

iTrader: (15)

Garage List
I know people are selling their OEM units and fetching $150-200 and that's for an uncut system! I just can't sell it for such a small amount of money, I may need it again someday, who knows. So for now it will be 'wall art' in my man cave(garage)!

Name:  ART.JPG
Views: 908
Size:  43.2 KB
__________________
Appreciate 0
      07-27-2009, 06:19 PM   #16
swamp2
Lieutenant General
swamp2's Avatar
United_States
214
Rep
10,201
Posts

 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

iTrader: (1)

I would bet the tubing is hydroformed, this process uses very high fluid pressure along with a "mold" for the outside shape desired. The tubing is very purposefully shaped into a non round cross section in certain sections. My guess (without looking under my car recently) is that it is for clearance - either to other parts of the chassis or to the ground.

On another note we debated the need for exhaust shields quite a bit on this thread. My conclusion was just what IND is saying above. A user installed heat sheild sounds like a darn good way to play it plenty safe with any aftermarket exhaust system. Link to that thread here.
Appreciate 0
      07-27-2009, 07:34 PM   #17
lucid
Major General
lucid's Avatar
United_States
116
Rep
8,034
Posts

 
Drives: E30 M3; Expedition
Join Date: Apr 2007
Location: USA

iTrader: (0)

As I stated in the other thread, I really don't think the shields are there to block the radiation into the diff because the amount of heat generated and transferred by the diff is much more than the amount of heat transferred via radiation through that small patch of the exhaust pipe. Plus, the diff gets pretty hot to begin with, so the delta_t between the diff and the exhaust pipe would be somewhat low.

Ilia@IND, how do you know the CV joints melted because of the heat radiated from that part of the exhaust as opposed to the heat conducted by the diff? Did the problem go away after you installed shielding? And on what type of car was the failure you described happen? Finally, do you have any sense of how hot exactly that part of the exhaust gets during hard driving? The answer to that question would inform the discussion we were having in the other thread. Thanks.
__________________
Appreciate 0
      07-27-2009, 07:43 PM   #18
Mr.Metak2you
Brigadier General
Mr.Metak2you's Avatar
121
Rep
4,757
Posts

 
Drives: LEXUS LS(DailyDriver)
Join Date: Nov 2007
Location: Astral Projecting: ∞ 23.516 -122 02.625 0242.101 ĕv'rē-hwr'

iTrader: (15)

Garage List
Quote:
Originally Posted by swamp2 View Post
I would bet the tubing is hydroformed, this process uses very high fluid pressure along with a "mold" for the outside shape desired. The tubing is very purposefully shaped into a non round cross section in certain sections. My guess (without looking under my car recently) is that it is for clearance - either to other parts of the chassis or to the ground.

On another note we debated the need for exhaust shields quite a bit on this thread. My conclusion was just what IND is saying above. A user installed heat sheild sounds like a darn good way to play it plenty safe with any aftermarket exhaust system. Link to that thread here.

Thanks, I must have missed that thread. I am probably going to play it safe and get some sort of shield on my exhaust.
__________________
Appreciate 0
      07-27-2009, 08:52 PM   #19
Lemans_Blue_M
Automotive Industry Insider
Lemans_Blue_M's Avatar
United_States
19
Rep
1,948
Posts

 
Drives: Lemans Blue M3
Join Date: Aug 2007
Location: Texas

iTrader: (0)

Quote:
Originally Posted by swamp2 View Post
I would bet the tubing is hydroformed, this process uses very high fluid pressure along with a "mold" for the outside shape desired. The tubing is very purposefully shaped into a non round cross section in certain sections. My guess (without looking under my car recently) is that it is for clearance - either to other parts of the chassis or to the ground.

On another note we debated the need for exhaust shields quite a bit on this thread. My conclusion was just what IND is saying above. A user installed heat shield sounds like a darn good way to play it plenty safe with any aftermarket exhaust system. Link to that thread here.
Yes, the M3's OE exhaust system is manufactured by Arvin Meritor using an internal high-pressure hydroforming molding process.This technology allows them to manipulate the size and shape of the exhaust tubing to fit tight areas, that would normally cause clearance problems.

Without the use of this technology, it would lead to unwanted NHV in the interior cabin.

Arvin Meritor has been the primary OE exhaust supplier for BMW for several years. They were the first exhaust company to make a tubular exhaust manifold using this new hydroforming exhaust molding technology in the early 1990's.

They have a factory located in Spartanburg, South Carolina near the BMW plant.




__________________
The best is yet to come...
Appreciate 0
      07-27-2009, 11:04 PM   #20
rzm3
Moderator
rzm3's Avatar
224
Rep
4,603
Posts

 
Drives: E92 M3
Join Date: Aug 2007
Location: USA

iTrader: (14)

Honestly, most people won't see a difference. Most people have only had their cars for about one year max, less have aftermarket exhausts, and even less actually track it hard enough to see high temperature in the exhaust. If there are any problems with not having a shield, we probably won't see any reports until a bit later.

But the heat shield only costs like $40, so why not play it safe?

Lucid, if you could take some temp measurements during a track session, let us know.

__________________
E92 M3 DCT - AiM EVO4 Data Logger / AiM SmartyCam HD / KW Competition 2-Way / OMP ARS Racing Seats / Brembo GT 365 / Pagid Yellow RS-29 / Rear Seats Delete
Appreciate 0
      07-28-2009, 02:33 AM   #21
lucid
Major General
lucid's Avatar
United_States
116
Rep
8,034
Posts

 
Drives: E30 M3; Expedition
Join Date: Apr 2007
Location: USA

iTrader: (0)

Quote:
Originally Posted by rldzhao View Post
Lucid, if you could take some temp measurements during a track session, let us know.
I've actually measured the exhaust pipe temp at that exact spot on my aftermarket exhaust right after full-on track sessions at ~180C in the paddock, which seems pretty harmless. I suspect the actual average operating temps during a track session like that are actually much higher given the pipe is thin and cools off rapidly, but I didn't pin it down. I think you are right that if running without a shield significantly impacts the CV joints, it would surface in the long term. I don't currently have any issues with my CV joints (I check them regularly).
__________________
Appreciate 0
      07-28-2009, 11:26 AM   #22
Nate@IND
BimmerPost Supporting Vendor
Nate@IND's Avatar
479
Rep
10,442
Posts


 
Drives: BMW
Join Date: Oct 2006
Location: Chicago

iTrader: (19)

Quote:
Originally Posted by lucid View Post
As I stated in the other thread, I really don't think the shields are there to block the radiation into the diff because the amount of heat generated and transferred by the diff is much more than the amount of heat transferred via radiation through that small patch of the exhaust pipe. Plus, the diff gets pretty hot to begin with, so the delta_t between the diff and the exhaust pipe would be somewhat low.

Ilia@IND, how do you know the CV joints melted because of the heat radiated from that part of the exhaust as opposed to the heat conducted by the diff? Did the problem go away after you installed shielding? And on what type of car was the failure you described happen? Finally, do you have any sense of how hot exactly that part of the exhaust gets during hard driving? The answer to that question would inform the discussion we were having in the other thread. Thanks.

When our friends at Fall Line ran an OEM exhaust system, the CV boots did not melt, but after installing their competition exhaust system with no heat shields, they experienced quite a bit of trouble with melted CV boots. Since then, Fall Line has added heat shields to their competition exhaust, and it is this experience that leads me to believe that heat shields are necessary to protect the rubber CV boots.
__________________
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
Forum Jump


All times are GMT -5. The time now is 02:23 AM.




m3post
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