But you can also look at it this way... the idle, no-load timing would be excessive when the engine is loaded at launch. So you want the timing to drop back to centrifugal-only as the load comes on :)
That’s true...mostly. If the timing drops back too far it will be retarded for the load and make a bunch of heat. That’s why I try and make the curve delay a bit after initial timing is where I want it. Then you add in the VA timing while the mechanical advance isn’t adding any timing. Sometimes, depending on compression ratio, gearing, converter and such I try and delay the start of mechanical advance even without using an vacuum advance. Low throttle opening and transitory loads don’t always want more advance. If you give it more than it wants, you can get a tip in rattle.
