My 83 Turbo ZX manual says that all timing advance curves are adjusted by the computer according to factors like engine load, throttle valve angle, intake air temperature and density, and engine RPM, so I'm not sure that adjusting the timing manually at idle will give you any noticeable improvement in power. I do know that I put a Nitrous Oxide kit on my Turbo Zx, and drilled a tiny hole in the vaccum line going to the wastegate valve actuator, this increased my boost considerably. My only problem is the Pressure Relief valve on the intake manifold is letting some of this excess boost pressure go straight out of the intake manifold. It does'nt really matter to me though, because I still have a Sh*t load more horsepower and torque. I beat most slightly modified Mustangs in the quarter-mile because my car is so much lighter than theirs. Also, the nitrous acts as an intercooler too, adding even more power! My best time is 13.8 at 103 MPH, it's not too bad.
> What is the optimum advance for the 83
> 280zx? the label on my car shows an 8 degree
> but I've heard theres better. Anyone know?
I have an 81 zx and I use 8 degrees also. If your timing is off, you wont have better performance, you'll have worse. Before I set my timing, it was 16 degrees, and there was a noticable improvement in power. the timing is set so that the spark occurs just as the piston is approaching the top of the cylinder, so that it is at the top at the maximal output of the explosion.
If your timing is more agressive, the explosion will tend to prevent the piston from getting to the top, decreasing output from the previous cylinder, see what I mean? Set the timing to 8 degrees, and look elsewhere for improving output (you might start with a less restrictive exhaust and a larger bore air intake . . .).