Manley Single Piston with Rings / 79mm Stroke 99.50mm Bore | 2004-2021 Subaru WRX STI (612000CB-1)

Manley Performance
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EJ25 Platinum Series Lightweight Piston

Manley pistons are machined of high-strength 2618 material. Each design is lightweight yet robust enough to deliver long service life. Offset wrist pin design is utilized for quiet start-ups. Perfect ring groove to skirt squareness is achieved through our unique "one fixturing" manufacturing method that assures maximum horsepower. All pistons come with moly coated skirts. Round wire locks, premium chrome moly wrist pins, and premium steel top ring sets from Total Seal are included with every kit at no additional charge. 9310 alloy upgraded wrist pins are available. 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.


  • Bore: 99.50mm Grade B
  • Oversize: STD
  • Rod Length: 5.137"
  • Stroke: 79mm
  • Comp. Distance: 1.209"
  • Dome Volume: -22cc
  • Cylinder Head: 51cc
  • Comp. Ratio: 8.5
  • Piston Type: Dish
  • Piston Weight: 395g
  • Included Ring Set: 46995DT-1


  • 2004-2021 Subaru WRX STI
  • Subaru EJ257

What's In The Box?

  • 1 - Piston w/ Rings


  • Manufacturer Standard Warranty

    Customer Reviews

    Based on 4 reviews
    Great fit and finish

    Bern installed in my engine for about 10k now at 380/370tq hp. Doesn't use a drop of oil and and are decently quiet for being forged. Would recommend!

    Jacob Spidle
    Piston rings are different from grade A

    I ordered two grade A pistons and two grade B, and the oil rings are different between the two. It's a different procedure to install them, but they have the same instructions supplied in the box. So I was very confused, and pulled an already installed piston to make sure I did it correctly - perhaps it was an older model. For the A grade there was no notch for the oil ring tab, so I put it in the oil hole, similar to OEM. Better instructions for the newer type/grade B are here

    Julio Vallecillo
    Excellent and professional

    Thanks guys thanks Leo for taking your time helping me get what I need it everything fit perfect

    Nicholas Panozzo
    So far so good

    Just installed in an all B bored block... barely any piston slap at idle, goes away completely when at temp. Nothing bad to say. After blowing Ringlands at 450whp, this is for peace of mind. 2015 sti