Stage X Low Expansion Piston Set - WRX & STI 2006+ (V9+) EJ25

Forged low expansion piston set for WRX and STI 2006+ (V9+) EJ25 engines.

Why forged?

Forging is still the best way to make a piston, both for production and for strength. A correctly forged piston has an excellent grain structure; a piston machined from solid bar has no true grain flow. Forging creates optimal alignment within the material and, combined with the right heat treatment, gives the piston its strength.

Precision

The skirt is machined to a profile that works best at full operating temperature: elliptical rather than round, and barrelled along its length.

The pistons are individually weighed and batched to within 0.5 grams, so a set of four deviates by no more than 2.0 grams.