This makes sense now - and also makes other things make sense. I was having a chat with Stu the other day who was explaining to me that the best performance from the turbo was actually at the point when the wastegate begins to open.

I guess that at this point, we have a situation where the turbo is making peak boost, and the engine is allowed to flow maximum air. Cool - that actually makes sense now!

Credit also to Chip who explained it again on the phone to me today!

JJ