Which zetec? Do you mean like an early fiesta/escort type or the later focus 1.6 yamaha engine?

Anyway.. you turbocharge it the same as any other engine.. lower the compression ratio.. make it strong enough.. give it a turbo and more fuel and a suitable calibration to control it all

I reckon the 1.6 Zetec-E would make a lovely 200bhp turbo engine with a standard head.. not sure what valve springs you'd need though.