Forged Piston Kit - CP 12:1 Compression Ratio - 4AGE & 4AGZE 16VForged Piston kit 81. 5mm or 82mm Bore Size 12: 1 Compression Ratio for 4AGE & 4AGZE 16V 290 grams with a 20mm wrist pin. CP Pistons is one of the most trusted names in the industry, and for good reason. Their extensive shelf catalog provides the user with many of the options that you'd normally be resigned to going to a custom piston for. Their standard offering already includes Dual Pin Oilers providing double the amount of oil to the wrist pin,