sfort......solenoid reaction time is too slow to work well. AND, to get the force, the current draw would be horrendous. Solenoid valves run in the 60-70 Hz reaction time.....a 6000 rpm engine has a valve event at about 500 Hz rate but, in reality, it is much faster since part of the time, the valve is held open. Formula cars have pneumatic valve actuators but dont use solenoid valves in the air circuit because they are too slow also. Plus, the formula cars have extremely lightweight valve trains with ultra small and light valves.