with out knowing anything about your engine can't really say. unless your on a dyno with an AFR gauge, then i wouldn't go past 17* timing with about 11:1 AFR. But I don't know a thing about your combo or boost your running.:thinking:
haha @ taco comment. Ummm the answer to your question would be to pull 11% fuel out at wot and add 15 degrees timing anytime you see boost.