A quick note on timing: ideally timing is set to achieve peak cylinder pressure around 15-20* ATDC. This is the point where the cylinder pressure is most efficiently converted into power.

We have to compromise a bit due to the fact we also have to"feed" a turbine as well. Fuel octane also limits those of us who are using pump gasoline.

My point being that knock isn't the best way to get best timing (although it may the biggest limiting factor).

Mike