The new engine produces 197bhp, 11% more than its 1.6-litre turbo predecessor.
The induction and exhaust systems have been tuned to keep noise down and make the engine smooth at all revs.
Prices plus economy and emissions figures will be released during the engine's unveiling at Frankfurt.
The Cascada 1.6 SIDI turbo can be ordered from October, with the first UK cars arriving in January 2014.
By William Stretton