Originally Posted by rstdave
Na, didn't use a proper tester to be honest! Never used one in the past tho and not had the same problem! Just a bit baffled why it only overboosts in 3rd, 4th and 5th??? It's a new -31 actuator. Have to get hold of a pressure tester i spose.
The reason it boosts more in 3rd onwards is the engine is under more load. This always happens on big turbos, they will not produce their full boost in the lower gears. The actuator setting u used before means nothing. You should set the actuator to half a hole preload, that is the longest the rod can be, and with the bleed valve totally closed, this will be the lowest boost you can run.
Secondly, you need to get the car setup, as your going to melt it. The new turbo will be flowing a lot more air than the last.