Code No. 21004-AN015



φ86.5 Piston is available for SR20DET 2.2L KIT.
Users can select between φ86.5 (STEP1) and φ87.0 (STEP2) for condition of cylinder block or required specification of the engine.






Displacement of SR20 is increased from stock 1,998cc to 2,139cc.
The larger displacement will increase torque. It enables to be used with large flow capacity turbines.
*STEP2 φ87.0 is 2,164cc.

φ86.5 Piston is considered as STEP1 of 2.2L Kit. The surface treatment of STEP2 (φ87.0) is not done for STEP1 to achieve the affordable price. This kit is also recommended for overhauling purpose. Feel the power of 2.2L.
*Although it is STEP1, it is forged piston. Forged connecting rod and forged crankshaft are the same items as STEP2 that means the maximum target horsepower is the same.
*φ87.0 piston is STEP2. It has nickel plating, which is more durable against knocking, on the piston top and ober coating, which reduces friction, is on skirt portion.

MADE IN JAPAN (HKS in house production).


φ86.5 piston was newly developed as STEP1. It is strong forged piston.
(STEP2 has nickel plating, ober coating and titanium coating top ring.)



■Selection of STEP1 (φ86.5) or STEP2 (φ87.0)
Piston Bore (mm) 86.5 87.0
Displacement (cc) 2,139 2,164
Compression ratio (ε) G/K1.2mm 8.7 8.8
G/K1.6mm 8.4 8.5
G/K2.0mm 8.2 8.3
Crown height 4.8 4.8
Crown volume 15.3 15.3
Top coating - nickel plating
Skirt coating - ober coating
Remark /oil ring: 2 piece /top ring: titanium coating
/oil ring: 2 piece
Connecting rods same → Forged H-beam Connecting rods
Crankshaft same → Forged full counter crankshaft 



【Using an used cylinder block】
Due to deformation, with 0.5mm diameter boring and honing may not be able to have accurate circle bore. (Same for other engine models.)
In case bore is not accurate circle, pistons cannot be installed accurately. Therefore, φ87.0 STEP2 with 1.0mm boring and honing is recommended.
φ87.0 STEP2 has nickel plating, which is durable against knocking.

【Using new or good condition cylinder block】
φ86.5 is recommended so that φ87.0 can be used for the next overhauling.

【For performance enhancement】
φ87.0 in a new block is recommended. (Larger displacement will be better performance.)



Product Engine Capacity (ml) Type Boring・Honing modification Full flow modification Code No. Manual Remarks
SR20DET 2.2L Kit STEP1 SR20DET 2139 φ86.5 - φ22 Required Not required 21004-AN015 Forged Piston Kit + H Beam Connecting Rod _ Forged Fully Counterweighted Crankshaft. Not Compatible with RNN14