Put it on a load control/bearing dyno, measure torque output and start adding timing a degree at a time at the speed and load points you are trying to dial in. Sometimes this means doing a proper spark hook test and reviewing data after the run. Really helps to have a good understand of the dyno you are using so you can accurately plot your torque curves over each other.
Once your torque output levels off, back the timing up. How much you back it up will depends on the build, the fuel you are using and how much safety margin you want built in. Can you afford to blow it up? If yes then run it at max torque. If you can't pull out a few degrees and be a little safer with less power.
This is after you have already dialed in your airflow model to at least a 3% or less error. Then you can play with adding a little fuel and maybe adding some more timing.
28 degrees isn't unheard of but you will never truly know how much advance is required for best torque and no knock.
I think 26 degrees is a good max target for a GENIII on the street in a passenger car. If you have a heavier vehicle, you want a little less advance. Log knock on street driving as it can load a vehicle much different than a dyno depending on what kind of dyno you have access to.
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Originally Posted by fastslvblkcar
