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Thanks for the good wishes, guys
JKM removed and inspected my turbo and, as suspected, the casing around the 'Penny Valve' Wastegate has a small crack. When I was chatting with VW Racing about my problem yesterday, they said it was probably Wastegate area or Penny Valve as JKM had exhaustively tested other possibilities.
I'll post pics at the weekend - Am off to APS tomorrow.
My original turbo is a Rev C, whereas my 'new' one is Rev G but there's no obviously visible difference!
Instead of trying so hard to meet boost requests that we were seeing >90% effort in the data logs, we are now seeing as little as 65% and mostly in the 70's - So now there's plenty headroom (tolerance).
JKM also set my Revo to Boost 6 instead of 7. It'll run 7 fine but we decided 6 just as an extra margin of safety.
So initially she making just over 240 bhp with a very healthy torque curve but we need to let the whole ECU learn the new setup and settle before another dyno session.
The dyno has been invaluable as a tool for assessment and diagnosis and then checking everything afterwards. Jim did some road testing with the laptop as well.
JKM are a great team - Jim is the mechanical expert and Keith the electronics expert and they specialise in VAG cars.
The probable cause of the crack is heat - Turbo's are subjected to extremely high temperatures - And a weakness in the metal casing. At first it's easy to regret that it didn't happen while still under warranty but I doubt very much if VW would have accepted my issue with my other modifications being present. There have been cases of metal failure in the K03 turbo on standard 2.0T FSI engines, so it's not a problem exclusive to remapped engines.
It's great to have that extra power back!
