When conducting acoustic researches and finishing works on combustion engines specialized technological equipment
and tools mounted mainly in anechoic chambers are used. In order to ensure the high quality and objectivity of the research results of
the sound fields produced by the research object it is crucial to achieve a sufficiently low parasitic background noise produced by technological
equipment and tools of an engine test bench. The source of a high background noise re-emited to the anechoic chambers
interior is structural vibrations of the solid objects of load carrying and flatsheet box-type structures of the bench. The article considers
tested technical methods of improving vibroacoustics of load carrying and envelope structures of the engine test bench, which is in
startup, commissioning and preliminary operation phase in the research center of a car manufacturer. Therewith there was a requirement
to prevent any fundamental changes of the bench original basic construction, in order to minimize potential material and financial
expenses for its reengineering process. Tested design solutions allow to reduce the level of parasitic noise disturbances, produced
directly by the bench equipment in an anechoic chamber, up to 12 dBA.