What stroke has a max power of 109 ps(80kw)@4000 rpm?
CREATE TABLE "engine_reference" (
  "code" text,
  "vehicle" text,
  "year" text,
  "displacement" text,
  "bore" text,
  "stroke" text,
  "c_r" text,
  "max_power" text
);
SELECT "stroke" FROM "engine_reference" WHERE "max_power"='109 ps(80kw)@4000 rpm';