azmir: i wont be worried about compression if i were u coz if the compression totally fails u would have noticed it coz the car will shudder like a vibrator. On a good engine i would say its about 170-180 but note that however 135-170 are average depends on the abuse and the condition and year of usage of the engine itself.Borderline i think should be around 120, i think.
lets say if you have 165-150-155-165-158-110 across the six cylinder u might want to check out the one with the 110 reading. Normally cylinder #6 run leans and if there is a problem its always cylinder 6 because of the design of rb engines not getting nuff oil on number 6. If u get odd ones like cylinder 2 or 3 or anything in the middle u might have a major prob there.
btw, a major shite with the goverment removing RON97, anybody wanan share their thoughts of putting RON95 in our car? any impact on higher compression engines like RBs?