A rotary engine, parts thereof, and methods associated therewith is provided. The engine is modular and adjustable to accommodate a variety of requirements and preferences. The system includes a combustion assembly having a housing and a power rotor positioned therein. The power rotor rotates in a first direction from the beginning of each combustion process through the end of each exhaust process. The system also includes a compression assembly linked to the combustion assembly such that the compression rotor rotates in the first direction from the beginning of each intake process through the end of each compression process. A tank assembly in fluid communication with the compression assembly and the combustion assembly provides stability to the system while eliminating or otherwise reducing transitional loses.