Wow.. that's high... Boosting at 1.5 bars is something I will do if I am really hungry for power and there is no more option other than giving a last try out to achieve maximum power that my engine can produce... I mean for GSRs with stock internals... That's solely my point of view for being conservative on a daily drive car.
In most cases, engine don;t tend to produce power as expected/planned after modification is due to the tuning. A proper tunning will release extract more power than boosting higher... Most of the cases. Not all...
Well, back to your piston question. Most GSRs or BOTers change their pistons to TOYOTA 4agze pistons is because the coincidence of sharing the same bore with 4G92/93(t) and having least modification to be done to fit. Just the conrods. But personally, I do think GSR pistons are capable to take high boost due to the low compression crown profile. However, people get impressed by the "
semi forged with ceramic coated piston crown" of TOYOTA 4agze pistons. So, most ppl change to Supercharger pistons when they projecting high boost. I am one of them...
Well, when u want to boost really high, then there are far more better after market performance pistons compare to TOYOTA Supercharger pistons. CP, Wiseco, JE, Duratech and lot more.... Those are forged pistons that are capable of taking high boost.
Even conrods, there are aftermarket forged conrods that are stronger than the above mentioned conrods.... Duratech, brian crower, and etc...
But due to limited cost concern, ppl tends to use internals from other engine and put them together to build stronger engine to take higher boost safely.... Comparing a set of new TOYOTA 4AGZE pistons c/w rings only cost RM700+ and Wiseco 82mm that cost RM2K+...
And that's what we call ROJAK...