I'll share my insight. My supercharger was slow-ish and somehow seemed weak.
After receiving an electric shock from my supercharger ramp when installing a flasher, I measured and found the ramp itself to sit on +72 V.
Reason for this was the diverter coil, which had made contact to the ramp metal.
Fixing this issue did a lot to the game in terms of supercharger speed and general snappiness of the coils.
If you have a slow SC and dont know why, you might want to measure he voltage on the ramp. if it is at +72V, fix that and your SC times should improve.