JE Pistons Subaru EJ25 Ultra Series 8.5:1 (Set of 4)

If you're building a high-performance Subaru EJ25 engine, especially one that will see significant boost, JE Pistons' Ultra Series forged pistons are a solid choice. These aren't your average off-the-shelf pistons; they're packed with advanced features designed to handle the extreme pressures found in boosted applications. They're made from 2618 aluminum, a strong material commonly used in performance pistons, and come in a set of four with a 3.927-inch bore and an 8.5:1 compression ratio, which is ideal for forced induction builds.

What sets these Ultra Series pistons apart is JE's proprietary Aligned Grain Flow forging technology. This process maximizes the tensile strength of the aluminum, making the pistons incredibly strong and able to withstand the intense cylinder pressures that come with high boost. You also get a thermal barrier crown coating, which is a ceramic-based material that reflects heat back into the combustion chamber. This helps reduce piston crown temperatures and can improve how efficiently exhaust gases are scavenged. The skirts are coated to reduce friction and wear against the cylinder walls, which also helps quiet down operation, especially when the engine is cold. Plus, they feature lateral gas ports to help maintain a strong seal on the top compression ring, even at high RPMs and under heavy boost.

These pistons also include high-strength wrist pins from Trend Performance, designed specifically for the demands of power-adder engines. The pin oiling is optimized to ensure the pin, bores, and connecting rod small end stay well-lubricated, reducing heat and wear. Every feature on these pistons is geared towards high-horsepower racing engines, and they're made 100% in the USA. Keep in mind these are not CARB approved and cannot be shipped to California.