Hola Marcelo,
According to
GINFO Search Results Summary | Aircraft Register | Operations and Safety
most of the UK Turbulents are fitted with the Volkswagen 1600, some with the ARDEM 4C02 (based on the VW 1500?) and one has a Jabiru 1600.
I believe the original Tubulent was designed to be powered by the 30hp VW 1200.
Do you have the plans to complete your project? I imagine that it will be possible to fit a Rotax 447 or 503, but they will be lighter than the VW and require considerable modification of the engine support and cowling.
Donald