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HELP!--- AID-timing questions...(long) Posted by kenS [Email] ![]() ![]() |
I would like a reality check from the timing experts here--- I just installed an SPG9 AID on an '87900T, and I'm wondering if I did it correctly!
Basic timing, with the AID hose disconnected and plugged, was set to 19 or 20 deg. If I attach a mityvac to the AID and apply vacuum (about 15 inches), timing advances to 28 deg. If I apply positive pressure (about 10 psi), timing retards to around 8 or 9 deg. Applying more pressure didn't seem to add any more retard--- stayed at 8 or 9 deg. This is at standard idle (850-875 rpm). I did NOT try higher rpm's or engine loads.
The question is, do these settings sound about right? If I am going to limit my boost to 15 psi max, do I still need to worry about excessive retard and install a valve to bleed off pressure? Should I try and fine tune things any further than this, or look at timing settings at different rpm/ load factors?
Car is a 1987 900 turbo, 156K--- only other mods are stage I APC tweek, 2.8 bar fuel pressure regulator; still using stock injectors. I tried a quick test drive with the AID and it seemed to run ok--- boosts 1/3 to 1/2 into red (just below 15 psi limit switch).
posted by 12.234.20...
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