To shake or not to shake that is the question, when the gasifier and motor reaches an equilibrium?
Most of the time we are using the gasifier the throttle plates of the intake manifold are the bottle neck or restriction of the entire system . This includes the air entering the heat exchangers going through the complex fire tube housing, nozzles , wood , char bed and ash , grate back through the heat exchanger , cooling rails , hay filter , motor plumbing , throttle plate , intake manifold , the motor cylinders and out the exhaust .
Most of the time we are driving we can open or close the throttle to change the vacuum inside the motor as well as the vacuum in the gasifier. If we give more throttle the vacuum inside the motor decreases and the vacuum inside the gasifier increases.
There may be times when operating the gasifier that it reaches equilibrium. When opening the throttle more it changes no vacuum in the motor or the gasifier.
The gasifier can get in a state where the fine particles and the char depth can restrict the system more than the throttle settings.
One has reached this point when, for example, opening the throttle from ¼ to ¾ throttle has no effect on the system and the gauges stay the same.
This is no problem when out cruising especially on flat roads. You may be driving the speed limit or a comfortable speed. At this point the gasifier is usually making its cleanest gas and with the best efficacy.
If one has the need for speed, more power,rpms and air flow it only takes a flip of the grate shaker switch to open the restriction, but don’t over do it. If you over do it you have slipped char to the ash dump , thus wasting energy ( unless recycling the char after used) , loosened the char bed enough that oxygen might make it beyond the gate ( heater mode) and the possibility of making some tar.
My rule of thumbs are if I have enough power to do what I am doing, not to shake.