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Old 05-18-2013, 02:41 AM   #76
dpm
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Someone would need a head in their hands to probe the route of the SAS ducts- or at least look inside the exhaust ports with the headers off. The ducts however definitely communicate with the valve cover through the central spark-plug gasket, between the plugs.
Look at the first pic in the valve clearance thread, the two holes are obvious.
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Old 05-18-2013, 07:05 AM   #77
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Originally Posted by dpm View Post
Someone would need a head in their hands to probe the route of the SAS ducts- or at least look inside the exhaust ports with the headers off. The ducts however definitely communicate with the valve cover through the central spark-plug gasket, between the plugs.
Look at the first pic in the valve clearance thread, the two holes are obvious.
These pics from Oso Blanco's valve adjustment procedure?

Quote:
Originally Posted by Oso Blanco View Post





Yes, I think those are the channels (ducts) we are talking about. Couple other pictures that would be helpful; first, the underside of valve cover gasket to see how the channels match up to the reed valves. Second, the underside of a disassembled head to see where the channels exit into the exhaust port.
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Old 05-18-2013, 07:15 AM   #78
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Originally Posted by jscottyk View Post
These pics from Oso Blanco's valve adjustment procedure?



Yes, I think those are the channels (ducts) we are talking about. Couple other pictures that would be helpful; first, the underside of valve cover gasket to see how the channels match up to the reed valves. Second, the underside of a disassembled head to see where the channels exit into the exhaust port.
Good of you yo post those pictures. We are getting somewhere now..... It looks like the two holes in the middle matches up with the two reed valves, as you explained. So if we assume that those two channels goes to each bank's exhaust chamber, them we have a deal.
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Old 05-18-2013, 07:19 AM   #79
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Originally Posted by ebrabaek View Post
Good of you yo post those pictures. We are getting somewhere now..... It looks like the two holes in the middle matches up with the two reed valves, as you explained. So if we assume that those two channels goes to each bank's exhaust chamber, them we have a deal.
Given that BMW touts Secondary Air as a pollution feature, I've seen enough to be convinced that that is what they are. ...

I think you should pull the connector to your solenoid at least although it may cause an error code. Otherwise this air will fool Autotune.
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Old 05-18-2013, 07:37 AM   #80
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Originally Posted by roger 04 rt View Post
Given that BMW touts Secondary Air as a pollution feature, I've seen enough to be convinced that that is what they are. ...

I think you should pull the connector to your solenoid at least although it may cause an error code. Otherwise this air will fool Autotune.
Agreed...... So, if I pull the plug on the system, by plugging the hose going from the valve in the airbox, to the reed valves on the valve cover, how do you suppose the BMS-K, can know of this...... Disconnect the valve, yes....but just plugging the line, simulating a stoppage, not so much. From another angle, I thought you mentioned somewhere earlier, that the SAS system would be compatible with the PC-5....or did I not read that correct, and it was not compatible with the PC-5, and compatible with the LC-1....????
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Old 05-18-2013, 08:12 AM   #81
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Quote:
Originally Posted by ebrabaek View Post
Good of you yo post those pictures. We are getting somewhere now..... It looks like the two holes in the middle matches up with the two reed valves, as you explained. So if we assume that those two channels goes to each bank's exhaust chamber, them we have a deal.
Yes, I think we are very close. Consider this description form Joel earlier in the thread.

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...From the reed valve, the path of the second air circuit is through a channel in the valve cover into a channel in the head. For this purpose, there is a stand alone gasket between the valve cover and head. This gasket is entirely internal. If this gasket leakes, 2 things can happen. 1: exhaust pressure can enter the internal engine and raise crankcase pressure, likely leading to oil leaks. 2: oil can enter the second air circuit creating exhaust smoke and deposits in your exhaust system. For these reasons, this internal gasket should be replaced every time the valve cover is removed! Want to know if your dealer is adhering to this BMW reccomendation? Ask them if they stock this gasket the next time your in for a valve adjustment check. If they don't, I would politely decline to have your service completed untill they do stock this gasket. (note to self, check that my dealer does stock the second air gasket. Just kidding, we do :)
I believe not replacing the second air gasket is one of several reasons F800's develop more oil leaks then the F650's do, and the valve cover gasket is the weak point where the pressure creates oil leakage. Just as common the valve cover is warped, but in either case, using a whole tube of rtv to glue down the valve cover is not the answer ( insert video of bones saying "my god man! drilling holes in his head is not the answer, the artery must be patched" (startrek 4))

Last in the system are chanels in the head they exit right above one or both cylinder exhaust valves. I say "one or both" because I simply can't remember if there's just one or two channels. Sorry, perhaps I have a picture that shows the exits from the one and only rotax twin I've torn down. Will check and post the answer and link to picture if I do.
...

Man, I would to see these videos!
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Originally Posted by JoelWisman View Post
There is no diagram of the system I'm aware of on the publically available service DVD, or the dealer only RSD.

There is however a great video complete with animations at BMW university, a web site that's only available to BMW employees. I have no idea why BMW keeps stuff like this secret, but they do...
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Old 05-18-2013, 08:19 AM   #82
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Quote:
Originally Posted by roger 04 rt View Post
Given that BMW touts Secondary Air as a pollution feature, I've seen enough to be convinced that that is what they are. ...

I think you should pull the connector to your solenoid at least although it may cause an error code. Otherwise this air will fool Autotune.
I'm curious about that code.

Double posting this from the Dynojet PC-5, with Autotune thread...

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Originally Posted by jscottyk View Post
...keep in mind the F650 twins did not include this setup at all. None of the pieces. The valve cover is even different. Does anyone know if the F650 twin uses a different version of firmware in it's BMS-K?
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Old 05-18-2013, 08:34 AM   #83
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Originally Posted by ebrabaek View Post
Agreed...... So, if I pull the plug on the system, by plugging the hose going from the valve in the airbox, to the reed valves on the valve cover, how do you suppose the BMS-K, can know of this...... Disconnect the valve, yes....but just plugging the line, simulating a stoppage, not so much.
That could be one way of not causing an error condition for the BMS-K:
  • Disconnect the hose from the valve cover
  • plug the entry into the valve cover
  • tuck the hose away somewhere safe but leave it open
  • Then do not disconnect the solenoid at all


Quote:
Originally Posted by ebrabaek View Post
... From another angle, I thought you mentioned somewhere earlier, that the SAS system would be compatible with the PC-5....or did I not read that correct, and it was not compatible with the PC-5, and compatible with the LC-1....????
My understanding of Roger's description is the SAS would be compatible with a Wideband O2 setup since the BMS-K is still controlling the close loop/open loop functions and only injecting secondary air during periods of open loop. But not compatible with Autotune because the PC-V has no way of knowing what is happening with SAS and could be injecting air while Autotune is taking measurements.
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Old 05-18-2013, 09:19 AM   #84
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Quote:
Originally Posted by jscottyk View Post
That could be one way of not causing an error condition for the BMS-K:
  • Disconnect the hose from the valve cover
  • plug the entry into the valve cover
  • tuck the hose away somewhere safe but leave it open
  • Then do not disconnect the solenoid at all



My understanding of Roger's description is the SAS would be compatible with a Wideband O2 setup since the BMS-K is still controlling the close loop/open loop functions and only injecting secondary air during periods of open loop. But not compatible with Autotune because the PC-V has no way of knowing what is happening with SAS and could be injecting air while Autotune is taking measurements.
This is a good plan and how I would explain why it works with LC-1 and not with PCV.

For sure, whenever SAS comes on the Autotune values will be wrong since extra O2 will enter the exhaust and disturb the Wideband O2 readings, making the exhaust seem like it has more O2 than it does, resulting in a leaner reading.
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Old 05-18-2013, 10:03 AM   #85
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Port into exhaust shown clearly here right above exhaust valve face:



The channels run down the head from those small holes with o-rings, and go to each of the inside only exhaust ports right above the exhaust valve face.



Here you can see the ports with the o-rings. One o-ring is missing here to show groove they sit in.



My only question now is exactly what gasket is Joel referring to when he says it is crucial that it be replaced when valve cover is removed. My only guess is the gasket that has the two holes for the spark plugs. If so, doesn't that come as a set with the perimeter cover gasket. Unless you remove the cam top holder, you would not need to replace those two small o-rings on the secondary air passages.
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Old 05-18-2013, 10:17 AM   #86
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Good stuff jttele! Thanks for the pics!


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Originally Posted by jttele View Post
My only question now is exactly what gasket is Joel referring to when he says it is crucial that it be replaced when valve cover is removed. My only guess is the gasket that has the two holes for the spark plugs. If so, doesn't that come as a set with the perimeter cover gasket. Unless you remove the cam top holder, you would not need to replace those two small o-rings on the secondary air passages.
Exactly! I was wondering the same thing. Another mystery!
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Old 05-18-2013, 04:53 PM   #87
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Originally Posted by roger 04 rt View Post
This is a good plan and how I would explain why it works with LC-1 and not with PCV.

For sure, whenever SAS comes on the Autotune values will be wrong since extra O2 will enter the exhaust and disturb the Wideband O2 readings, making the exhaust seem like it has more O2 than it does, resulting in a leaner reading.
Yup, adding more fuel and increased decel popping. But, that's already been discussed. Not a BMW mechanic, but I did sleep at a Holiday inn
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Old 05-18-2013, 06:16 PM   #88
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Excuse the ignorance but, what if you were to move the O2 sensor to a spot after the SAS adds air, like welding a bung in the pipe further back?

Would that not solve the SAS problem without having to disconnect it and risk throwing an error code all the time?
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Old 05-18-2013, 06:31 PM   #89
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Excuse the ignorance but, what if you were to move the O2 sensor to a spot after the SAS adds air, like welding a bung in the pipe further back?

Would that not solve the SAS problem without having to disconnect it and risk throwing an error code all the time?
It's already setup that way. The SAS is adding air in the exhaust port of the head. The O2 sensor is #13 in this picture.


The purpose of this O2 sensor (sometimes called a lambda sensor) is to read the amount of oxygen in the exhaust gas. From this reading a pre-combustion air fuel ratio can be calculated by the engine control unit (the BMS-K on this model of BMW). The problem is the SAS is introducing fresh air (full of O2) into the exhaust after the combustion event thereby diluting the reading.
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Old 05-18-2013, 06:39 PM   #90
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Originally Posted by jscottyk View Post
It's already setup that way. The SAS is adding air in the exhaust port of the head. The O2 sensor is #13 in this picture.


The purpose of this O2 sensor (sometimes called a lambda sensor) is to read the amount of oxygen in the exhaust gas. From this reading a pre-combustion air fuel ratio can be calculated by the engine control unit (the BMS-K on this model of BMW). The problem is the SAS is introducing fresh air (full of O2) into the exhaust after the combustion event thereby diluting the reading.

Got it. Thanks for the clarification.
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