how to take out timing under boost?

Ive got a 2006 4.3 truck with vortech s/c, I just run a patch fix for timing. I dont really take out any timing, just copied the regular octane spark tables over to the high octane spark tables and run that, along with methanol injection/intercooler.

This gives me more octane (92-96+ octane w/ or w/out meth), and the pcm's spark table thinks it is 89 octane. Anyone know how much timing this would be equivalent of taking out?

I'm trying to get more efficient, get back a mpg or two with my tune. So I want to run full timing while not under boost, take out 1-2 degrees at 10psi, then work up to 3-4 degrees taken out at full boost (14psi). It'd also be the correct way for me to do this.

But with meth and an intercooler I could still be okay running just 1-2 degrees of timing taken out at 14 psi, but I wanted to be safe


I don't tune fuel anymore with HPTunders, I have secondary injectors with their own computer that comes on with boost (SDS EIC)

anyone? this really cant be hard I just need some advice to put me in the right direction

For my 3800, boost doesn't occur until 0.32 g/cyl so I would only add timing for MPG from 0.08 to 0.28 g/cyl. You need to scan and find out at what g/cyl you see a MAP of 100kpa or higher. HTH.