FAQ on Carbon Build-Up Issue (First Attempt) - Page 19 - BMW M5 Forum and M6 Forums
E39 M5 and E52 Z8 Discussion 1998-2003 Advertiser's Forum

Reply
 
LinkBack Thread Tools Rating: Thread Rating: 1 votes, 5.00 average. Display Modes
post #181 of 952 Old 14th September 2005, 08:36 PM
wilsodh
M5 Expert (>4000)
 
wilsodh's Avatar
 
Join Date: Jul 2005
Location: Chicago IL
Posts: 6,923
Thanks: 927
Thanked 857 Times in 461 Posts
Re: FAQ on Carbon Build-Up Issue (First Attempt)

Quote:
Originally Posted by mottati
I also find that interesting. Especially when you consider that the M5 was available in europe in 99, so there is a larger number of older, higher milage cars with older design piston rings, so more oil consumption. 10/60 seems to be more widespread in the s62 in europe (they do not use 5.30, but do seem to use castrol slx, which i think is 0w30).
Mike
Kin Mak (Ireland) confirmed off-line that his car is at the high end of the oil-consumption spectrum (1L/300-500 mi). His early '99 build car has 50,000 miles of mostly low speed city driving (currently averaging 17 mph), and yet has not had a carbon build up fault. Kin Mak would seem to be a poster-child for bringing on the problem if the main issue is oil consumption (no offense Kin Mak!). We also have greg (CA) who's early '00 has 97,500 mi with consumption @ 1 qt/1000 mi, yet has not has a problem. greg alluded to a cleaner-burning gasoline in California in his poll response.

It is fascinating to consider these data along with Norgeiron (Honolulu), who had a verified carbon build up problem at only 17,000 miles. Just thinking out loud, but I find myself wondering more and more about the contribution of the gasoline quality to this problem. Maybe we should take a closer look at possible regional & geographic differences in gasoline formulations to better fill out the picture...

Cheers,
Dave

'00 Royal Red/black/walnut M5
100% options, angel eye upgrade

'El Diablo'
00 Black/black DA s/c M5
Carrillo rods, Arias pistons,
Schrick cams, Vortech T-trim,
Supersprint headers/exhaust,
UUC, Koala driveshaft/differential,
Dinan Stage 3 suspension, Brembo
~Built by Shadowman & Black M5~
wilsodh is offline  
Sponsored Links
Advertisement
 
post #182 of 952 Old 14th September 2005, 10:43 PM
Kin Mak
m5board.comoholic (>1000 posts)
 
Kin Mak's Avatar
 
Join Date: Mar 2005
Location: Dublin, Ireland
Age: 36
Posts: 1,047
Thanks: 0
Thanked 4 Times in 3 Posts
Re: FAQ on Carbon Build-Up Issue (First Attempt)

Quote:
Originally Posted by mottati
Keep in mind that US 93 octane (R+M/2) equals about 98 octane in europe. 95 is about 90 here, which is our 'midgrade' in most markets.
Mike
Hi Mike

Could you clarify that? How is our rating different from yours? Is is not a standard?

Kin

BMW E46 M3 SMG Carbon Black/Cinnamon
BMW E39 M5 Avus Blue - SOLD
Kin Mak is offline  
post #183 of 952 Old 14th September 2005, 11:02 PM
mottati
Moderator
 
mottati's Avatar
 
Join Date: Oct 2002
Location: sf east bay ca.
Posts: 9,902
Blog Entries: 1
Thanks: 181
Thanked 349 Times in 279 Posts
Re: FAQ on Carbon Build-Up Issue (First Attempt)

Quote:
Originally Posted by Kin Mak
Hi Mike

Could you clarify that? How is our rating different from yours? Is is not a standard?

Kin
Hi Kin,
There are a couple of different 'octane rating systems' out there. In most of europe, you use the "research" octane number, RON. There also exists a "Motor octane number" which i've never seen used as a stand alone rating. In the US, to complicate things, we use the average of the two, hence my mention of (R+M)/2 so, in general, our octane rating at the pump is about 5 units lower than your posted RON. Our super unleaded for the most of the US is 93, in california the max you can find is 91. A few states have 94 as well.

Mike

93 M5 3.8 Sterling Silver, Black 5/93 production (euro)

94 M5 Touring Madeira Schwarz, Black 10/93 production

90 325iS, Black/Natur 5 speed

00 528i, sport Biarritz Blue, Sand

93 Range Rover County LWB, Roman Bronze

09 335d Japanrot/Black, No I drive, Sport, H&R/Koni, Logic 7

91 M5 Alpine White II, Silver Gray 3/90 production (sold)

00 M5 Silver, imola red/black sportive 6/00 production (sold)
me---> www.diablovalleyeyes.com
mottati is offline  
post #184 of 952 Old 14th September 2005, 11:04 PM
Kin Mak
m5board.comoholic (>1000 posts)
 
Kin Mak's Avatar
 
Join Date: Mar 2005
Location: Dublin, Ireland
Age: 36
Posts: 1,047
Thanks: 0
Thanked 4 Times in 3 Posts
Re: FAQ on Carbon Build-Up Issue (First Attempt)

Quote:
Originally Posted by mottati
Hi Kin,
There are a couple of different 'octane rating systems' out there. In most of europe, you use the "research" octane number, RON. There also exists a "Motor octane number" which i've never seen used as a stand alone rating. In the US, to complicate things, we use the average of the two, hence my mention of (R+M)/2 so, in general, our octane rating at the pump is about 5 units lower than your posted RON. Our super unleaded for the most of the US is 93, in california the max you can find is 91. A few states have 94 as well.
I see says the blind man...
Cheers for the clear up.

Kin

BMW E46 M3 SMG Carbon Black/Cinnamon
BMW E39 M5 Avus Blue - SOLD
Kin Mak is offline  
post #185 of 952 Old 15th September 2005, 05:09 PM
wilsodh
M5 Expert (>4000)
 
wilsodh's Avatar
 
Join Date: Jul 2005
Location: Chicago IL
Posts: 6,923
Thanks: 927
Thanked 857 Times in 461 Posts
Re: FAQ on Carbon Build-Up Issue (First Attempt)

Quote:
Originally Posted by mottati
Hi Kin,
There are a couple of different 'octane rating systems' out there. In most of europe, you use the "research" octane number, RON. There also exists a "Motor octane number" which i've never seen used as a stand alone rating. In the US, to complicate things, we use the average of the two, hence my mention of (R+M)/2 so, in general, our octane rating at the pump is about 5 units lower than your posted RON. Our super unleaded for the most of the US is 93, in california the max you can find is 91. A few states have 94 as well.
I haven't had a chance to look into this, but what do we know about gasoline additives; in particular, what makes a gasoline 'cleaner burning', as supposedly is the case for California gas. When refiners formulate with 'detergents', what really are these, and how do they contribute to less carbon buildup (as mainline oil companies like to advertise)?
Don't expect you to have all the answers, just thinking out load and downloading some of my own questions....

Cheers,
Dave

'00 Royal Red/black/walnut M5
100% options, angel eye upgrade

'El Diablo'
00 Black/black DA s/c M5
Carrillo rods, Arias pistons,
Schrick cams, Vortech T-trim,
Supersprint headers/exhaust,
UUC, Koala driveshaft/differential,
Dinan Stage 3 suspension, Brembo
~Built by Shadowman & Black M5~
wilsodh is offline  
post #186 of 952 Old 16th September 2005, 05:52 AM
jaj
Member, P500, DSC On (>600)
 
jaj's Avatar
 
Join Date: Sep 2002
Location: Vancouver, BC
Posts: 626
Thanks: 0
Thanked 64 Times in 23 Posts
Re: FAQ on Carbon Build-Up Issue (First Attempt)

First, a big vote of thanks for LLcoolM5 for his effort on documenting the problem and what he found when he literally dug into it!

If you think about the way that solid buildup arises, there are a few key points:

- it builds up in the pipe that links the valve and the two cylinder heads. Presumably the heads as well, but certainly the pipe.

- it's a mix of carbon and some sort of binder. Pure carbon is unaffected by xylene or toluene, so for it to slowly dissolve, there must be a "goop" that's actually holding it together.

- the only sources for the carbon and the binder are the fuel and the oil. The S62 runs rich most of the time, and most rich at large throttle openings. This is the most likely time for carbon/goop to be created and available to go into the passages and the cross pipe.

- the carbon/goop mix must get into the cross-pipe when the circumstances are right. It's unlikely that it gets there when the smog pump is running because it would have to flow against the compressed air current from the pump.

- logically, the carbon/goop mix most likely gets into the pipe when the engine is at full (or nearly full) throttle (so that it has exhaust back-pressure behind it) and the engine is warmed up enough that the smog pump is turned off.

- to get into the pipe, it would seem necessary that the flow control valve that cuts off the smog pump and isolates the two arms of the cross pipe would have to leak in order for the carbon/goop to flow into it. Otherwise air pressure in the plumbing held in place by the closed valve would keep it out.

The big question for LLcoolM5 (or Shadowman, or anyone else that's actually taken these things apart) then is "in your opinion and from what you've seen, is it possible that the whole problem is caused by a faulty control valve?"

I'm very interested in this whole issue!

Cheers
JJ
jaj is offline  
post #187 of 952 Old 21st September 2005, 06:41 PM
wilsodh
M5 Expert (>4000)
 
wilsodh's Avatar
 
Join Date: Jul 2005
Location: Chicago IL
Posts: 6,923
Thanks: 927
Thanked 857 Times in 461 Posts
Re: FAQ on Carbon Build-Up Issue (First Attempt)

Quote:
Originally Posted by jaj
The big question for LLcoolM5 (or Shadowman, or anyone else that's actually taken these things apart) then is "in your opinion and from what you've seen, is it possible that the whole problem is caused by a faulty control valve?"
I thought I'd give this thread a bump back to the fore since it has been sitting idle for a few days. I am having some discussion with a BMW trained technician (now independent) that might be helpful. I'll pass along any useful information.

As for the faulty control valve, it might help explain some divergent data (why some cars have the problem early on, while others do not). I wonder if the 'dead air' that would reside in the secondary air pipe between the head opening and the closed control valve would not normally be displaced (perhaps slowly) by the turbulence that goes on in the combustion chambers, even if the valve was working properly. Indeed, if combustion gases did find their way into the pipes, the relative lack of air flow combined with the lower temperature in the pipe might provide ideal conditions for carbon/goop condensation. But I'm just guessing...

Cheers,
Dave

'00 Royal Red/black/walnut M5
100% options, angel eye upgrade

'El Diablo'
00 Black/black DA s/c M5
Carrillo rods, Arias pistons,
Schrick cams, Vortech T-trim,
Supersprint headers/exhaust,
UUC, Koala driveshaft/differential,
Dinan Stage 3 suspension, Brembo
~Built by Shadowman & Black M5~
wilsodh is offline  
post #188 of 952 Old 21st September 2005, 08:17 PM
DavidS
Moderator
 
DavidS's Avatar
 
Join Date: Dec 2001
Location: Lund, Sweden
Age: 45
Posts: 2,977
Thanks: 8
Thanked 107 Times in 27 Posts
Re: FAQ on Carbon Build-Up Issue (First Attempt)

Quote:
Originally Posted by jaj

- to get into the pipe, it would seem necessary that the flow control valve that cuts off the smog pump and isolates the two arms of the cross pipe would have to leak in order for the carbon/goop to flow into it. Otherwise air pressure in the plumbing held in place by the closed valve would keep it out.
The valve only isolates the smog pump from the tube. It does not isolate the two ends of the tube from one another. Therefor, when a differential pressure exists between the two heads exhaust gas will flow in the tube.

I wonder if cars with an X-pipe exhaust system are immune to this problem?
(The X-pipe connects the exhaust tubes from both heads together before the catalytic converters and thus lower the instantaneous differentil pressure between the heads.)

(In a previous post in this thread I have suggested adding two more one-way valves serving to isolate the two ends of the tube from one another.)

David

2000 M5 LeMans blue/Silverstone sport interior, double glass windows, all options except alcantara ceiling and trailer. Michelin PS2 tyres.

How to test the MAFs yourself:
http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/54788-how-test-mafs-yourself-how-mafs-work.html

Some further useful threads and info:
http://www.m5board.com/vbulletin/e39-m5-e52-z8-discussion/88323-davids-som-useful-threads-info.html
DavidS is offline  
post #189 of 952 Old 21st September 2005, 08:32 PM
mottati
Moderator
 
mottati's Avatar
 
Join Date: Oct 2002
Location: sf east bay ca.
Posts: 9,902
Blog Entries: 1
Thanks: 181
Thanked 349 Times in 279 Posts
Re: FAQ on Carbon Build-Up Issue (First Attempt)

Quote:
Originally Posted by DavidS
I wonder if cars with an X-pipe exhaust system are immune to this problem?
(The X-pipe connects the exhaust tubes from both heads together before the catalytic converters and thus lower the instantaneous differentil pressure between the heads.)

David

David the factory exhaust already has an H pipe type of crossover, so the exhaust should be ballanced. this is after the cats but before the resonaotors, same place the supersprint X pipe is installed.
Mike

Mike

93 M5 3.8 Sterling Silver, Black 5/93 production (euro)

94 M5 Touring Madeira Schwarz, Black 10/93 production

90 325iS, Black/Natur 5 speed

00 528i, sport Biarritz Blue, Sand

93 Range Rover County LWB, Roman Bronze

09 335d Japanrot/Black, No I drive, Sport, H&R/Koni, Logic 7

91 M5 Alpine White II, Silver Gray 3/90 production (sold)

00 M5 Silver, imola red/black sportive 6/00 production (sold)
me---> www.diablovalleyeyes.com

Last edited by mottati; 21st September 2005 at 08:36 PM.
mottati is offline  
post #190 of 952 Old 21st September 2005, 08:41 PM
DavidS
Moderator
 
DavidS's Avatar
 
Join Date: Dec 2001
Location: Lund, Sweden
Age: 45
Posts: 2,977
Thanks: 8
Thanked 107 Times in 27 Posts
Re: FAQ on Carbon Build-Up Issue (First Attempt)

Thanks, Mike!

I learn something new every day.

Then leakage in the valve isolating the smog pump from the tube seems the most likely reason for the exhaust gas flow into both ends of the tube.

David

2000 M5 LeMans blue/Silverstone sport interior, double glass windows, all options except alcantara ceiling and trailer. Michelin PS2 tyres.

How to test the MAFs yourself:
http://www.m5board.com/vbulletin/showthread.php?t=54788

Some further useful threads and info:
http://www.m5board.com/vbulletin/showthread.php?t=88323
DavidS is offline  
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the BMW M5 Forum and M6 Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes Rate This Thread
Linear Mode Linear Mode
Rate This Thread:



Similar Threads
Thread Thread Starter Forum Replies Last Post
Carbon Build Up - How Common is it? chunpng E39 M5 and E52 Z8 Discussion 42 21st December 2006 12:46 AM
carbon fibre CAI intake funnels CA Automotive M5 E39 Group Buy Forum and Sponsor Discussion and Offerings 8 24th February 2006 03:27 PM
Carbon Fiber Plenum Covers from D/A Sean@D/A M5 E39 Group Buy Forum and Sponsor Discussion and Offerings 11 16th July 2005 11:36 PM
WHY DOES OUR CARBON SEEM EXPENSIVE ? CA Automotive M5 E39 Group Buy Forum and Sponsor Discussion and Offerings 5 18th June 2005 06:45 PM
"ORDER / PRODUCTION SUMMARY" ( Note : See First Post For Instructions ) Alan A E39 M5 and E52 Z8 Discussion 82 17th March 2002 06:50 AM

Posting Rules  
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome