I have an Apex AFCII set to zero with Unichip tune. Got Chevron 91 octane gas this morning. When i started my car about 5 minutes ago, it started to knock around 30-34 on the meter. Could it be my gas or something else? Its pretty hot out side s well. Any help would be appreciated. Thanks..

 

Raising the octane will help. Retarding timing a few degrees will help too. Maybe your map is running too lean for the hot weather... Maybe you just got some bad gas if nothing has changed on your setup and it just started knocking. All just guesses on my part.

 

Do some research on how octane is tested at the refinery you will see this has little or no relavance to a modern performance engine.

Octane computer test at refinery have little correlation to what may come out of the pump nozzle a week or two later nor how your engine reacts.

Also winter grade and the transfer to summer grade [May1] may take a few weeks to trickle thru the system. California gasoline is always suspect.

Try some ultra premium racing fuel blend and note the results.