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The best aftermarket Subaru piston company just got even better with our new Turbo Tuff lineup targeted specifically for EJ25 engines. By incorporating proven design enhancements from our "Formula-Won" piston forging, we've created the ultimate Subi piston to withstand the rigors of the highest boosted and stressed applications yet still run "quietly" and trouble-free for the daily driver. Like all Manley Subaru pistons, these are made from 2618 alloy, utilize an offset wrist pin design, are skirt coated and include our standard 2.500" x .180" wall premium chrome moly wrist pin (P/N 42346).
Premium steel top rings with Napier style second rings and higher tension oil rings for ultimate oil control are included with each set along with round wire locks.
Recommended clearance: .003" for mildly boosted and .0035" for highly boosted measured .850" (79/83mm Strokes) and 1.100" (75mm Stroke) from the bottom of the oil ring groove.
Manley Subaru EJ257 pistons now include Napier style second rings and higher tension oil rings (by Total Seal) for superior oil control.
These pistons feature skirt diameters that correspond to the OEM Grade A or B bores resulting in a piston to wall clearance range of .0023” - .0031”.
Check the bore grades on the top of your block and order the appropriate quantities of Grade A or B pistons.
Features
- "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.






