advantage of slipper skirt piston
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Pistons with slipper skirts are lighter in weight. Reducing piston weight is one of the steps taken to get to a high rpm engine.
It would help if you posted the kind of vehicle and engine you’re asking about. Also, what kind of RPMs are you planning to operate it at (that require slipper skirt pistons)? Is this the only change you’re making or are you making similar enhancements needed to sustain high RPMs.
Advantage: lighter weight, less reciprocating mass.
Disadvantage: scuffing, binding. The piston skirt keeps the piston axially oriented in the cylinder.