What year(s) was the race status piston?
CREATE TABLE table_181892_4 (year VARCHAR, race_status VARCHAR)
SELECT year FROM table_181892_4 WHERE race_status = "Piston"
### Context: CREATE TABLE table_181892_4 (year VARCHAR, race_status VARCHAR) ### Question: What year(s) was the race status piston? ### Answer: SELECT year FROM table_181892_4 WHERE race_status = "Piston"