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      06-29-2008, 10:19 PM   #82
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Drives: 09 AW E92 M3 w/DCT
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Originally Posted by scalbert View Post
I will keep it simple as I believe you are set in your beliefs. That said, I have taken the DP's off, applied vacuum, tested vacuum at multiple points which none support what you have stated. If you apply vacuum to either tee, both wastegates close.
No need to keep it simple for me. I agree with this portion of your statement. I think you should re-read what I wrote. If the yellow hose is connected between the Tees, yes the vacuum would be the same.

Originally Posted by scalbert View Post
In fact, if BMW designed it the way you suggest, it would be an awful design
Please do me a favor and read what I posted. I did not suggest BMW should have designed it this way. I suggested that if Shiv had bypassed it this way, that the piggyback would have had control of the rear wastegate actuator. My reference to BMW was that they did it the correct way. Perhaps I need to make my statements more clear.

Originally Posted by scalbert View Post
You might as well run a single solenoid like the B5 S4. The dual set up is to provide quicker response than a single could provide while still providing a back up mechanism.
Duh. This is the whole point I am making. Why bypass something that is meant to make the system more efficient? Why do so in a manner that removes control from the rear system?

Originally Posted by scalbert View Post
That two inch section of tubing does not act as a buffer for anything. Unless there is orifice plate or sintered filter in between, the vacuum at the tee, and subsequently the actuators, will be the same.
Nowhere did anybody say buffer. It (the yellow hose as BMW designed it....just to be clear) is a damper to smooth response. It can't act as a backup if the solenoid fails. All a solenoid does is open or close and allows the pressure to temporarily equalize. If it fails to open, there is no connection between the two sides. BTW, when solenoids open and close and the pressure is not equal on both sides, pressure pulses are created, hence the reason for the yellow tube between the solenoids.

Once again, my point is that the bypass, not the design of the existing system, is a poor method and an example of poor engineering.