Supertech Subaru/Toyota FA20/4U-GSE 86mm Bore 12.5:1 CR Pistons - Set of 4 (Excl Rings)

If you're rebuilding the engine in your Subaru FA20 or Toyota 4U-GSE powered vehicle and aiming for a significant bump in compression, this set of Supertech forged pistons is a solid choice. These pistons are designed to increase the compression ratio to 12.5:1, which can lead to improved power output when paired with appropriate tuning and supporting modifications. The 86mm bore size is specific to these popular four-cylinder engines, ensuring a proper fit for your rebuild.

Forged pistons like these are built to handle the increased stresses that come with higher compression and more aggressive engine builds. They are made from strong aluminum alloy, which is then forged into shape. This process creates a denser, more durable piston compared to cast pistons, making them more resistant to detonation and mechanical fatigue. This particular set is for the 86mm bore common in these engines and features a 12.5:1 compression ratio. Keep in mind that these pistons do not include piston rings, so you'll need to source those separately to complete your engine assembly.

When undertaking an engine rebuild with higher compression pistons, proper engine management and fuel system upgrades are crucial to take advantage of the increased power potential and ensure reliability. It's also important to note that these pistons are not CARB approved and cannot be shipped to California. Always refer to your vehicle's specific service manual for detailed installation procedures and torque specifications.