Fuel Map Scaling

[SterlingM]

I would like to change the fuel usesd in my racecar from 98 octane to 93 octane. Is it possible to rescale the map and then use a datalog to make minor adjustments or is a full retune required?

This is on a Motec M600

[David Ferguson]

I would not expect you to need to change the fuel map with octane.

If your engine is knock limited with 93 octane, then you would probably want to have the ignition table updated on a dyno, with audio knock detection equipment used.

Or you could just reduce your overall ignition timing a few degrees at high load to be safe.

[SterlingM]

Thanks David. I just got the car over the weekend so I'll start digging into the Motec software and see what I can figure out. I know we'll log a few sessions and see how it looks from there.