What is the limit on compression for 91 octane gas before you need to start messing with the timing?

Im just curious if its even worth bothering trying to run my motor on 91 with 100% stock compression once its boosted.

 

if you are gonna boost even if you motor is stock in my opinion you should run at least 91 or 93 if you can get it



boost + engine knock = blown ring lands

 

Oh thanks for providing us the details about it.Its so helpful.