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<DIV>----- Original Message ----- </DIV>
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<DIV style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black">> Are
you sure that isn't vacuum retard?</DIV>
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<DIV dir=ltr class=gmail_attr>
<DIV dir=auto><FONT size=2></FONT><BR></DIV>
<DIV dir=auto> Yea, I wrestled with that for ages when restoring my car.
The early Biturbo turbos blow through the carburetor, which is enclosed in the
plenum. When boost comes up, vacuum advance fails so the other capsule takes
over. Its a nasty, complex system with flow restrictors in various
vacum/pressure lines to retard reaction time. It almost destroyed my love of
dynamic systems! :-P</DIV><FONT size=2></FONT></DIV>
<DIV dir=ltr class=gmail_attr><FONT size=2></FONT> </DIV>
<DIV dir=ltr class=gmail_attr><FONT size=2>Ah of course - boost kills 'vacuum'
advance, so 'pressure' advance takes over.</FONT></DIV>
<DIV dir=ltr class=gmail_attr><FONT size=2></FONT> </DIV>
<DIV dir=ltr class=gmail_attr>... When preignition or pinking occurs, the
computer modulates the waste gates to reduce the boost.</DIV>
<DIV dir=ltr class=gmail_attr><FONT size=2></FONT> </DIV>
<DIV dir=ltr class=gmail_attr><FONT size=2>For a long time I messed around
trying to get a 'knock-sensing retard' system onto the MGB, but the engine is
so noisy the knock sensor was triggering all the time! Early BL computer
controlled systems used that instead of (or maybe as well as) fixed maps,
suddenly tread on the throttle to pull away and you could hear it pink like
billy-oh, then rapidly reduce as the system retarded. Had it worked it
would have largely taken the place of centrifugal and vacuum advance, but
never mind.</FONT></DIV>
<DIV dir=ltr class=gmail_attr><FONT size=2></FONT> </DIV>
<DIV dir=ltr class=gmail_attr><FONT
size=2>Paul.</FONT></DIV></DIV></DIV></BLOCKQUOTE></BODY></HTML>