An alternative is to use transorb, or add Zener in series with diode (cathode to cathode) to raise the clamp voltage to around 60V. The higher clamp voltage will significantly speed the solenoid release. The stored coil energy discharges at the higher voltage, and power is current times voltage. A voltage clamp around 60V will reduce or eliminate arcing, and also reduce starter run-on. Fuel injector circuits employ a similar clamp to reduce off time of fuel valving.
