Hey guys
Im having an issue with a BF xr6t which we have done a turbo back exhaust, larger intercooler, 1150cc injectors etc.
We have had the wastegate bore machined with larger flapper, and a turbosmart actuator. Had issues on the dyno with overboost close to 20psi.
Turned off closed loop boost control and lowered wastegate duty as low as possible, but found still overboosting.
Bypassed complete boost control system, running the wastegate just off spring pressure which was 12psi, found still overboosting.
Tried a 7psi spring to see if removing boost earlier would help found still going over spring pressure.
Removed Actuator and bench tested off turbo, and found it opens at 7psi.
So this leads me to believe that i have an issue with my internal wastegate bore size being to small or a restriction on my actuator rod or flapper arm,
which is causing it to open late or not open enough.
Currently stripping it down to see what i can find. Has anybody had similar issues?
What should be the optimum internal bore size after machining?
What angle should the flapper roughly be at when wastegate is fully open? i see it can only open so far due to fouling on flapper pivot.
Thanks in advance