Vacuum operated cutout?
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I've been working (lackadaisically) on various cutout
schemes, haven't gotten to the vacuum scheme other
than acquiring a big box of vacuum actuators.
It seems like a decent scheme other than that some
regions of operation are likely to partially-open the
butterfly (like where mid-throttle low RPM drops
vacuum to below the counter-spring force). And it
is uncommon to find a biscuit with a lot of stroke
length, short ones mean a short arm and a weak
holding force -> rattling plate.
So far my efforts make me prefer a solenoid-closed,
spring-opened scheme. But I also kind of like the
idea of a pressure operated biscuit, that takes the
exhaust gas pressure off something like the EGR or
AIR fittings (I know there is significant pressure at
the head of the Y, because I've blown out O2 sensors
at WOT) and the pressure-biscuit would be working
off exactly what it's meant to mitigate.
Solenoid-open, spring-closed in my experience is
too weak to not rattle, closing strength being set
by the wrong end of both spring closing force and
solenoid pull-in force.
schemes, haven't gotten to the vacuum scheme other
than acquiring a big box of vacuum actuators.
It seems like a decent scheme other than that some
regions of operation are likely to partially-open the
butterfly (like where mid-throttle low RPM drops
vacuum to below the counter-spring force). And it
is uncommon to find a biscuit with a lot of stroke
length, short ones mean a short arm and a weak
holding force -> rattling plate.
So far my efforts make me prefer a solenoid-closed,
spring-opened scheme. But I also kind of like the
idea of a pressure operated biscuit, that takes the
exhaust gas pressure off something like the EGR or
AIR fittings (I know there is significant pressure at
the head of the Y, because I've blown out O2 sensors
at WOT) and the pressure-biscuit would be working
off exactly what it's meant to mitigate.
Solenoid-open, spring-closed in my experience is
too weak to not rattle, closing strength being set
by the wrong end of both spring closing force and
solenoid pull-in force.