Part Number: 21004-AT009

Description: HKS High Comp Capacity Upgrade Kit 2.5L Stroker Step 2

Fitment: 22+ Subaru BRZ / 22+ Toyota GR86 N/A

Notes: Not for sale in California not CARB Legal

Details:

The 86 platform has come a long way, and the current GR86 and BRZ twins have been offered a myriad of ways to make power. From cold air intakes to complete exhaust kits to ethanol tunes and everything in between. Well, HKS is here for that extra kick in the form of their Step 2 Capacity Upgrade Kit for the FA24 flat-four, enlarging your second-gen car's displacement from 2.4 to 2.5 liters! Experience a much-appreciated dallop of lower-range torque as well as strengthened internals for low-boost applications thanks to their upgraded pistons, piston rings, crankshaft, and connecting rods.

Step 2 is strongly recommended for higher-horsepower, high boost applications in turbocharged HKS GTIII-RS and supercharged cars HKS GT2. The thicker, stronger machined I-beam connecting rods will better resist the immense pressures of such builds, enabling you to crank up the power and stay off embarassing forum posts for bent con rods!

Features:

• Forged high-compression pistons for higher strength.

• Allowable torque has been increased by adopting high-strength I-beam connecting rods.
  *STEP 1: Forged split connecting rods
  *STEP 2: Machined connecting rods

• STEP 2 is recommended for supercharged/turbocharged cars.

• Forged crankshaft for strength and reliable increased stroke.

• Highly durable connecting rod bearings are used.

POINT-1: Piston Kit

• To prevent the breakage of the second land, the material employs A2618 material, which has high-temperature strength, to achieve a low pin height that eliminates the need for making any service holes.

• 2-layer molybdenum coated to help reduce friction.

• The cavity on the piston head optimizes the atomization of direct injection.

• 3D Piston crown shape sustains tumble flow.

• The uneven shape of the piston head allows using the high-lift camshaft.

POINT-2: Connecting Rod

STEP2

• Provide a dedicated high-strengthened billet connecting rod for the long stroke. Any clearance modifications to the stock engine block are unnecessary because of a specially designed crank pin.

• Optimized wall thickness based on strength analysis. Achieved approximately 30% increase in strength, which minimizing weight gain.

• I-beam shape was selected to increase the buckling strength.

• Manufacturing by the billet to makes it possible to ideal thickness shape and eliminate the damaged starting point on the surface. The surface is also exposed to a powerful shot penning process to improve fatigue strength.

• Optimum heat treatment is performed on the chrome-molybdenum steel to enhance its strength and toughness.

POINT-3　Crankshaft

• Crankshaft uses a forged material.

• It has a dedicated pin journal size. Combination use of the HKS connecting rod is recommended.