O2 (knock) sensor experts plz

[JShadzi at aol.com]

<< Well, you misled me with the O2 sensor intro, I was all set, but now I'm a
 little un-schooled.  Anyway, I think you're right, the sensor is basically a
 piezo-electric microphone. I don't think that it generates a variable voltage
 (per se) but that the Control unit interprets the sound for knock and retards
 timing until it this sound drops below threshold. Timing is then advanced 
until
 it detects knock. It attempts to hold timing just before knock occurs. 
>>

Whoops, sorry, my mistake!
 
 > I am working on a timing retard device based on boost for NA cars.
 
 Why do you need boost-based timing retard on a NA car... :-) 
 
 Nah, I get your question, and actually Saab used a system called APC in their
 late 80's turbo cars (86-93 900, 86-89 9000). Find one in the junkyard and 
pull
 the pieces. 
 
 Here's a great site that shows all the info (apparently Volvo guys use the
 system too). Shows pieces you need, location on car, and how to install. 
 
 http://www.teleport.com/~bertram/volvoapc/index.shtml  >>

Cool, I cheked out the site, looks interesting.
Javad