[Flr Power]

Tripling the hp would not mean the bolts sees 3x the stress imposed on it. Normaly, the crankshaft pulley bolt sees abnormal stress when an imbalance occur between the pulley and crankshaft. Is the pulley vibration free when you look at it and rev the engine?

Also some drivers can be pretty hard when they force the engine acceleration rate to change abruptly. Like when upshifting, downshifting and releasing the clutch very fast.