Complex sentence: Many manufacturers are reducing engine capacity and number of cylinders but adding turbochargers and direct injection technology to provide a powerful engine with similar perfomance to a much larger engine but with much improved efficiency and reduced carbon emissions.
Split into simpler sentences: Many manufacturers are reducing engine capacity and number of cylinders. By adding turbochargers and direct injection technology, they provide a powerful engine with similar perfomance to a much larger engine, but with much improved efficiency and reduced carbon emissions.