11.5 on an N/A car at wide open throttle is too rich, especially on a VQ motor. It will kill power and too rich of mixture can knock just as much as too lean. Most people will find the "sweet spot" around 12.3 - 12.9 at wide open throttle, then you adjust timing accordingly for the best power output. At idle and normal cruise you want to be around 14.7 for best fuel economy. Anything leaner, you may have idle and backfiring / exhaust popping issues.
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'08 Infiniti G37s - Forced Induction Fed
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