I just picked up a 1990 Audi 90 20V quattro 2 days ago.. struggling to find info as easily as it is on vortex and other VW sites.. This place looks pretty good however.. Already on car I have a few questions.. Timing. Where should be set at and at what RPM do you set it. I will just run premium (91 octane) if it lets me run more advance. I had timing gun out yesterday and verified all cylinders had something going on with every plug wire (inductive gun was triggering off spark that is). I also checked compression and got about 130 psi on every cylinder. It was idling rough. I read somewhere else to advance timing some. At about 2500 rpm (as best I could tell by sound from under hood) it was showing about 12+ is that too much.. It runs smooth and don't appear to be pinging. Thanks for your help. I live over 7200 feet elevation so i think a 20V turbo swap is in order hehe.