OM603 semi-super pump testing, fitted with Bosch 6.0mm elements
OM603 semi-super pump testing, fitted with Bosch 6.0mm elements
You could try drilling out the bleed orifice on the WG body and threading it to accept a needle valve. That will keep the valve closed longer and give a little more adjustment range. Or even brazing a counter-boost fitting onto the atmosphere side of the actuator.