Been lurking and reading lots on here, but as my chequebook build NB2 has been performing faultlessly, I have not been posting much. I am hoping for some troubleshooting help though now.
The car has been perfect on road for a year, and for its first turbo'd trackday session over the weekend. The car was not as happy in the second session though, I was getting significantly more lag than normal and the car felt slightly down on power even when reaching full boost.
Datalog graph below shows the difference between session 1 and session 2 on the same 6 second slice of corner entry to exit.
You can see how much more throttle I needed to use in session 2, and how much slower the boost builds in this session.
Any tips on where to start looking? I cannot see any leaks in the exhaust manifold, nor in the plumbing from turbo through intercooler to intake. Maybe the wastegate is staying slightly open, but cannot think how to test that?
The engine bay was getting quite hot, not sure if that is relevant. Coolant temp reached 228F (109C), oil temp was reaching 262F (128C) but manifold air temp was steady at 105F (40C) in both sessions.
Full spec for reference:
- 245bhp at the hubs, at 16psi.
- Standard VVT engine.
- e_1 manifold for Tial V-band housing and Tial MV-S external wastegate
- e_1 3" down pipe with re-introduced wastegate dump
- Garrett GTX2860RS with uprated metal bearing carriers and stainless heat shield
- Tial MV-S 38mm external wastegate with .4bar spring fitted
- Pierburg high-frequency boost solenoid
- Custom centre section reduces to 2.5" for Flyin' Miata catalytic converter
- Stock rear exhaust section (cat-back)
- Vibrant intercooler from Fab9
- Fully TIG welded hard-piped intercooler run
- Tial Q50 BOV
- Flyin' Miata Stage 1 clutch
- EV14 620cc/min fuel injectors
- Vishnu dual feed fuel rail
- MsLabs Basic MS3 with closed loop fuel and knock control enabled (and setup on dyno)