each object in scene hierarchy should use the name that game can recognize. You can't assign arbitrary names (well, you can, but you'll get a warning of unknown object name). Additionally, game behavior with unknown objects is unpredictable: it can ignore them and draw the model fine, or these objects could cause conflict with other parts.
In your case, the engine model should be a part of game-known "chassis" object. If your object exceeds limitations, you can group several objects and assign this group as L0 component.
The filter will learn object names/IDs when you import models. Thus, for example, if you import some original model with some specific names in it, the filter will remember them and will not report "unknown object name". Of cause, I assume you import GTA5 model file for the filter to learn names.