Yes, but...... in most cases when people talk about "20psi boost" they tend to mean atmospheric pressure PLUS 20psi e.g. 14.7+20=34.7psi total, but when people talk about "turbo boost limited to 2.5 BAR", they normally mean 2.5 x atmospheric pressure e.g. 2.5x14.7=36.75psi total.
i.e. 1 BAR generally means 0psi boost (14.7psi absolute at sea level).
The following pages help explain the relationship between inches of mercury, psi and BAR, etc:
http://www.intendedacceleration.com/html/tip_1.html
http://www.sjmautotechnik.com/10vgauge.html