ziemniak was propagated in place of kartofel
pyra (Great Poland), kartofel (from German), barabola (Lwów), kompera (£emko - Beskid), grula (górale - Eastern Podhale), bulwa (Kashubian), perka (from Peru), rzepa (Western Podhale, Orawa).
So it was not just the fight between ziemniak and kartofel. :-). I can confirm that pyra and grula are definitely still in use.
Other examples that I remember:
- szlafrok => podomka = dressing-gown
- nakastlik (from German: Nacht (night + something)), apparently still in use => szafka nocna = bedside table, bedside cabinet