I agree I think trying to run ideal ignition timing is not as popular as it was in the past. I still think you should try to stay as close to ideal timing as possible.
Food for thought, the aircraft folks probably have done more testing and development on high performance piston engine in high load environments than all the automotive folks combined.
Many of them have timing fixed near ideal timing for max power. The way they handle max power for take off is they richen the mixture until the engine runs rough and then crank up the boost to the maximum recommended manifold pressure ( just short of det).
I think we should look more at managing boost pressure curves and less with playing games with the ignition timing.
I think the issue is it is much easier from a control system point of view to solve problems by pushing the timing values all over the map. It is much more difficlult to get fast acting stable boost control with enough head room so you can reach knock limited performance at high rpm with boost rather than ignition timing.
Most street turbos simply can't deliver knock limited boost at high rpm.
So they fake it by jacking in a lot of ignition advance, and create an electronic variable compression ratio by lighting the fire a bit early. It works to a point, but in theory it should not produce as much power as maintaining ideal timing and running the boost necessary to reach the knock limit.
Larry
|