The common name for that is "waste gate".

On the 1992 that is controlled by the EDS box and a vacuum transducer. The flow is maifold pressure -> MAP sensor -> EDS controller -> vacuum transducer -> vacuum actuator -> waste gate.

There is a mod thread out there for converting the waste gate actuator to a simple pressure type. Mainfold pressure -> pressure actuator -> waste gate. Hmm which one has less things that can go wrong???

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech