Quote:
Originally Posted by arcosine
I don't like over square engines. Fine for performance, but not fuel economy. combustion surface area increases buy the bore squared. 100 mm bore has 50% more area than a 80 mm bore.
• Prius:
1,497 cc 1.5 liters in-line 4 front engine with 75.0 mm bore, 84.7 mm stroke, 13.0 compression ratio.
Honda CRX HF: Engine Bore/Stroke 75.0x84.5mm
Saturn S series: 82 Bore× 90 mm stroke
Honda Insight: 72 bore × 81.5 mm stroke
Subaru EJ25
Displacement: 2457 cc
Bore: 99.5 mm
Stroke: 79.0 mm
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And the most efficient mega diesels in giant ships have a 3 foot bore and a 9 foot stroke, with a scotch yoke to eliminate piston side loads. Longer stroke means a better lever. Not many short stroke engines are in the top percentages for best BSFC.
regards
Mech