re- boost controller options- autoworlds article

[Alan Pritchard]

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Hmm autoworlds article seemed very good, until i thought about it....
For those who havent read it the author installed a "pop off valve" in his
actuator line, the idea being that until x psi is reached the wastegate does
not open, thats fine, but then he needed a way of setting the maximum boost
level.  So he installed after the pop off valve a pressure regulator and set
it 1 psi above that of the first valve.  The idea of the regulator is that
when it reaches its set psi it will not allow any additional pressure
through, thats sounds ok you all say, BUT this isn't regulating inlet
pressure, this is regulating wastegate actuator pressure therefore the
wastegate actuator can not recieve any additional pressure than that is set.
So he was wondering why sometimes he was gettin 12.5 psi, rather than the
set 11 psi. So here goes....
Boost is rising but the wastegate is not opening, when 10 psi is set in the
wastegate line the pop off valve opens and allows the wastegate to start
opening but the wastegate can not open as fast as possible because of the
pressure regulator set at 11 psi, therefore while the wastegate is still
opening to its full amount the turbo is still spooling!!!!!!