it was only boosting to 0.5 bar when i was putting air into the engine, from a compressor, to do the boost test.
ive been out in the car today, the car drives fine it boosts to over 1 bar boost, and the 1st & second turbos come online when they should.
holds boost, doesnt feel like a boost leak.
but its just making a hissy/whistle, loud spooling noise when the 1st turbo comes online.
ive got the BOV working & sounding correct again (i had the vacuum for it Td into the boost controller vacuum, not on its own)
as the car is boosting fine, and the second turbo is coming in fine, i think the noise maybe coming from the intake manifold side, or a vacuum, or idle valve etc.
ill have a play about with it next week to sort. im still worried though that the hissy whistle noise maybe making the 1st turbo overwork & go bang