Recently replace my aging Speed Demon 750 with a new one with anular discharge boosters. My preignition problem went away. 9.8 comp had been to much for available 91 octane. Can the new booster be that much better at atomizing? I have been using a water/meth injection system.

Secondly I chased a problem for a long time to finally find an idle fuel limit jet loose.(pressed in to the metering block.) Fixed it and then the threads for the bowl screws pulled out. Alcohol in the fuel?

Thoughts?