Part Number: 21004-AT008

Description: HKS High Comp Capacity Upgrade Kit 2.5L Stroker Step 1

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 1 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 1 is an excellent choice for people looking to keep their cars naturally aspirated and are merely looking for a dose of torque or for those going forced induction (see HKS GTIII-RS turbo and HKS GT2 supercharger)and keeping boost levels at a conservative level.

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

STEP1

• Exclusive conrods designed for longer stroke. The crank pin size is designed for a dedicated size. Thus it eliminates the modifications on the engine side.

• It optimizes the connecting rod bolt size and employs the high-strength split-type (not machined the cutting surface) I-beam.

POINT-3　Crankshaft

• Crankshaft uses a forged material.

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