Right, bit of a strange one to me. Had a blast round silverstone at japfest and noticed an issue with boost.
Going to add a picture of the track to help explain
My issue seemed to occur in 3rd gear on the exit of Beckett's and 4th gear coming out of woodcote.
I had a couple of leisurely laps to get me warmed up and used to the track, the car was already up to temperature but wanted to let the tmic cool a bit. Once I was happy I went for a good fly about while grinning like a Cheshire cat. Unfortunately my fun was spoiled when the car didn't feel like it wanted to boost when applying the gas on the exits. It would get to about 0.6bar and felt like it was holding back. I'd have to let off the gas get straight and then gun it again. No issues when straight. Full throttle and full boost all the way. Once it hit that low boost it didn't matter if I applied more throttle or not it would just hold back until I let off and got flat.
Don't feel like I've explained that to well but any help will be appreciated.
Few bits of extra info:
It had just over half a tank of fuel. It wasn't boost cut it would just seem to hold revs/boost until I let off and got flat. No CEL came up during or after it happening. Air filter and plugs were replaced within 500 miles of trackday. No detrimental signs since. I've pushed it on way home from silverstone and it done everything it should.
Good luck!