S60 14L GT4708 what is a safe max psi boost ?

Just a little background, I have a S60 14L Pre EGR with a GT4708, ECM reprogrammed, high flow donaldson intake filters, turbo boost controller set at 40 psi, pyro temps post turbo on a hard pull 520C / 968f maybe a little higher at times. Turbo builds 40 psi very very quickly with no hesitation. My question /concern is - how high psi is safe for a S60 , I read somewhere that a GT should not go above 50psi, but what about the engine of a daily used engine that earns money to put food on the table ? I'm thinking that my setup will easily build an extra 5psi to 10 psi (45psi to 50 psi) but is that safe and reliable ? P.s the boost reaches 40 psi around 1450rpm and I change gears at 1650/1700 rpm so that's 1 reason I'm looking at increasing boost psi.

 

Thanks, I finally managed to find a little info on here also.

My plan is to reduce EGT a little, so next weekend I'm match porting the exhaust manifold, installing Donaldson M100463 muffler, installing turbo blanket and exhaust wrap. Then I will monitor EGT and water temps and see how things are, if EGT are still above 480c (900f) I will increase boost to 45 psi and see what happens. Trial and error , sometimes I hate myself for being so fussy!

 

So I have the answer after what seems a eternity, the max boost on a factory/stock Pre EGR 14L series 60 GT4708 turbo should be 38psi, below is a little info to help explain why 38psi is the max boost you want it to be;
38psi @2100rpm = 108 lb/min & 70% efficiency and any higher than 38psi @ 2100rpm will be off the compressor map, which is bad.

38psi @1700rpm = 87.5 lb/min & 73% efficiency

Just for reference, the stock setting of 32psi @1700rpm = 75 lb/min & 76% efficiency


As you can see 38psi @ 1700rpm = 87.5 lb/min and that is 12.5 lb/min more airflow getting into the engine at the same RPM. Or a little over 16% increase in airflow.