{"product_id":"manley-04-subaru-wrx-sti-ej257-std-stroke-99-75mm-25mm-bore-9-8-1-dish-piston-set-with-rings-612102c-4","title":"Manley 04+ Subaru WRX STi (EJ257) STD Stroke 99.75mm +.25mm Bore 9.8:1 Dish Piston Set with Rings - 612102C-4","description":"\u003cp class=\"font-claude-response-body break-words whitespace-normal\" dir=\"ltr\"\u003e\u003cstrong\u003eManley Platinum Series Forged Piston Set — Subaru EJ257 99.75mm, 9.8:1 (612102C-4)\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\" dir=\"ltr\"\u003eA +0.25mm dished set at 9.8:1, built for the EJ25 under real boost. The -10cc dish is what drops compression to a level that tolerates high boost without pulling timing, and 2618 forged construction is what holds it together when you get there.\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\" dir=\"ltr\"\u003eManley redesigned this line specifically for EJ25 engines, incorporating proven enhancements from their Formula-Won piston forging. The result withstands the highest boosted and most stressed applications while still running quietly and trouble-free as a daily driver — which is the usual compromise with a 2618 piston, and the reason for the offset wrist pin design and moly-coated skirts.\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\" dir=\"ltr\"\u003eCam and barrel skirt profiles make substantial power while staying gentle on cylinder walls. Manley's single-fixturing method turns the skirt and machines the ring grooves in one operation, giving ring groove to skirt squareness you can't get from a two-op process. Pressure balance groove included, and the crown accommodates +1mm valve sizes if the head's been worked.\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\" dir=\"ltr\"\u003e\u003cstrong\u003eSpecs:\u003c\/strong\u003e 99.75mm bore (+0.25mm over), 1.209\" compression height, -10.0cc dish, 23mm wrist pin, 423 grams. Sized for 79mm stroke with a 142mm rod. Replacement ring set is 46997DT-4.\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\" dir=\"ltr\"\u003e\u003cstrong\u003eFitment:\u003c\/strong\u003e 06-14 Subaru WRX, 04-21 STI — EJ257.\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\" dir=\"ltr\"\u003e\u003cstrong\u003eSet your clearance correctly.\u003c\/strong\u003e Manley recommends .003\" for mildly boosted and .0035\" for highly boosted builds, measured .850\" from the bottom of the oil ring. This is a 2618 piston and it grows with heat — a tight bore is how these get scuffed.\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\" dir=\"ltr\"\u003e\u003cstrong\u003eBlock work required\u003c\/strong\u003e — +0.25mm means boring and honing to size.\u003c\/p\u003e\n\u003cp class=\"font-claude-response-body break-words whitespace-normal\" dir=\"ltr\"\u003eIncludes 4 pistons, Total Seal premium steel top rings with Napier second rings and high-tension oil rings, 4130 chrome moly wrist pins, and round wire locks. 9310 pin upgrade available.\u003c\/p\u003e","brand":"Street Strip Supply","offers":[{"title":"Default Title","offer_id":47228760195245,"sku":null,"price":720.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0779\/8105\/7197\/files\/611100-4_86d4caf0-0243-4478-b4d2-b0169b2a10fb.jpg?v=1786813734","url":"https:\/\/streetstripsupply.com\/products\/manley-04-subaru-wrx-sti-ej257-std-stroke-99-75mm-25mm-bore-9-8-1-dish-piston-set-with-rings-612102c-4","provider":"Street Strip Supply","version":"1.0","type":"link"}