Application: 2004-2013 Subaru Impreza WRX STi
Bore Size (mm): 99.75
Comp. Ratio: 9.8
Over Size: +0.25mm
Stroke: 83mm Stroker
Rod Length: 5.137″
Comp. Distance: 1.130″
Dome Volume (cc): -14
Cylinder Head (cc): 51
Piston Type: dish
Piston wt (Gms): 401
Included Ring Set: 46997-4

Note: Manley Sport Compact Platinum series pistons come complete with pistons, rings, pins, and locks

Manley’s signature “Platinum Series” pistons feature 2618 alloy forgings, proven cam and barrel skirt profiles, tool steel wrist pins, and moly skirt coatings on select part numbers. Join the ranks of professional engine builders and tuners who rely on Manley pistons for superior performance and durability.
2618 Alloy Forgings: We use domestic 2618 alloy forgings, ensuring superior strength and performance.Chrome Moly Wrist Pins: Premium Chrome Moly wrist pins come standard with our Standard Series Pistons. For select SKUs, we offer wrist pin upgrades to 9310 and Turbo Tuff/DLC alloys, providing additional durability.Exacting Ring Lands and Grooves: We adhere to strict standards for piston ring lands and grooves, resulting in enhanced ring seal and more power.Cam and Barrel Profiles: Our pistons boast cam and barrel (skirt) profiles that generate substantial power while being gentle on cylinder walls.Unique Fixturing: Manley’s unique fixturing allows for skirt turning and ring groove machining in a single operation, ensuring ultimate ring groove to skirt squareness.

Features: 

• Forging – 2618 alloy for maximum high temperature strength and fatigue resistance
• “Contour forgings” provide the optimum balance between strength and weight with no grain-interrupting internal milling.
• Proprietary multi-step top ring groove machining process assures optimum control of the groove’s size, geometry, flatness, and finish.
• All final turning is performed in one fixturing resulting in complete squareness of rings to the cylinder wall.
• Federal Form-Scan gauging validates ideal skirt indexing to pinhole and skirt-to-skirt polarity.
• Value – added features such as a pressure balance groove included in all series.
• Precise pinhole machining results in an exact compression distance as well as precise lock ring groove spacing, size, and concentricity.