JE Pistons Subaru EJ25 Ultra Series 99.50mm Bore Dia -16.5cc 8.5:1 - Piston Set

If you're rebuilding the engine in your Subaru EJ25, especially for a high-boost application, these JE Pistons Ultra Series pistons are a solid choice. They're built with JE's proprietary Aligned Grain Flow forging technology, which gives them next-level tensile strength to handle the extreme cylinder pressures that come with adding a turbo or supercharger. These aren't just basic pistons; they come with custom-level features that make a real difference in performance and longevity.

You'll find a thermal barrier crown coating on these pistons. This ceramic-based coating helps reflect heat back into the combustion chamber, which can reduce piston crown temperatures and aid in exhaust gas scavenging. The skirts are coated to reduce friction and wear against the cylinder walls, which also helps quiet down the engine, especially during a cold start. For maintaining a strong ring seal even at high RPMs and under heavy boost, JE has included lateral gas ports. Plus, they come with high-strength, thick-wall wrist pins from Trend Performance, designed specifically for the demands of power-adder builds. Every feature on these Ultra Series pistons is optimized for high-horsepower racing engines.

JE Pistons makes all of their products 100% in the USA, and these Ultra Series pistons are no exception. This set includes four pistons, each with a 99.50mm bore and an 8.5:1 compression ratio, featuring an inverted dome/dish design. Keep in mind that these pistons are not CARB approved and cannot be shipped to California.