Question: when did porsche go to water cooled engines
[{'answer': '1998', 'provenance': [{'wikipedia_id': '48345830', 'title': 'Porsche 911', 'start_paragraph_id': 1, 'start_character': 399, 'end_paragraph_id': 1, 'end_character': 403, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '48345830', 'title': 'Porsche 911', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 508, 'bleu_score': 0.6735064336858201, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10441051212699376102}, 'section': 'Section::::Abstract.'}]}]