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Old 02-15-2012, 11:41 AM
gary@germanautosolutions's Avatar
gary@germanautosolutions gary@germanautosolutions is offline
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Mein Auto: E39 528i, E60 M5
MJLavelle - Here is a copy/paste of the original question and answer. It's easy to miss in seven pages of posts.

Question: Is the diaphragm robust enough to handle the extra mass of the new flapper and pivot? I wonder if this fix will move the failure point of the DISA valve from the flapper to the diaphragm.
1) There is really no mass related load put on the vacuum actuator. The system moves slowly enough that the small rotational inertia difference if insignificant.

2) The vacuum actuator is fully loaded the entire time that the valve is in the closed position, which is most of the time. That aspect doesn't change with the aluminum parts compared to the plastic ones. Since the OEM design has the diaphragm under full vacuum load to keep the valve seated against the molded in silicone rubber gasket, and since that load is many, many times greater than the force required to rotate the valve, it's a non-issue. Just for reference, the new parts only weigh 13.5 grams more than the stock plastic valve with steel pin.



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