JE Pistons Subaru EJ257 Ultra Series Piston Kit - 99.50mm (Set of 4)

JE Pistons has built a reputation for making some of the strongest, most feature-packed pistons you can get right off the shelf, and their Ultra Series is a prime example. If you're building a high-boost Subaru EJ257 engine, this kit is designed to handle the extreme cylinder pressures that come with serious power adders. These aren't just basic pistons; they're packed with custom-level features that make a real difference when you're pushing the limits.

What sets these Ultra Series pistons apart is JE's proprietary Aligned Grain Flow forging technology. This in-house process maximizes the material's tensile strength, giving you a solid foundation for high-performance builds. You'll also find a thermal barrier crown coating, which is a ceramic-based material that reflects heat back into the combustion chamber. This helps keep piston crown temperatures down and can even improve how efficiently exhaust gases are scavenged. On the sides, a skirt coating is applied to reduce friction and wear against the cylinder walls, which also helps quiet things down, especially during a cold start. Plus, these pistons include lateral gas ports designed to help maintain a strong ring seal, even at high RPMs and under significant boost.

This kit includes four pistons, each measuring 99.50mm in bore diameter. They also come with high-strength, thick-wall wrist pins made by Trend Performance in the USA, built to handle the demands of power-adder applications. The optimized pin oiling features are there to ensure the pin, bores, and small-end stay well-lubricated, reducing heat and wear. Every part of this kit is made 100% in the USA, reflecting JE Pistons' commitment to quality and performance.