Aftercooler Solve Detonation Problems?

[Murdock]

I think you are running to much advance under boost. What is happening is when your on 91 octane only, the increased cylinder pressure (caused by boost) is causing the fuel to have a faster burn time. If you add timing advance to this situation you would be getting pre-ignition/detonation. The reason it goes away with a higher octane is because high octane fuel will burn slower so you are not getting pre-ignition. I would not suggest the timing adjuster for the soul fact if you retarded the timing 4 degrees to help with detonation at the top end you are also taking timing out from the bottom end. The best way to control timing with boost is with a boost timing retard box such as the MSD. You want to be able to run 14-16 degrees timing at low RPM and retard with high RPM. Remember you are running a centrifugal blower that needs to build boost.

A PMS is a piggyback system for your PCM from Anderson Ford. It lets you adjust the fuel and timing on NA or Blown applications.

Murdock