FORGED PISTON KIT + H-BEAM CONROD SET Explanation of the product Application chart

Code No. 21004-AN016




To improve the performance of R35 GT-R using the factory pistons and connecting rods, the durability of these factory parts restricts the improvement.

GT800 Package can release the restriction by replacing the pistons and connecting rods with the HKS Piston Kit and Connecting Rod Set which enables higher performance.

This HKS Piston Kit and Connecting Rod Set are the best to use with GT800 Package to upgrade the engine properly.




<POINT-1> High Output Part
  • The bore sizes of both Piston Kit and Connecting Rod Set are the same as the factory sizes so they can be replaced with the factory parts.
  • To avoid piston land breakage, HKS pistons are made with forged material instead of casting like the factory pistons.
  • It’s recommended to use with other items of the GT800 Package.
  • In-house test at 900PS confirmed the durability and safety.
  • The setting range is widened by reducing the compression rate from 9.0 factory ratio to 8.7. This is effective to increase the engine output using the aluminum block specs and/or bigger cylinder bore.


<POINT-2> Factory Replacement Type
  • The weight of the connecting rod is the same as the factory since the affect of the V6 engine’s peculiar vibration should be considered.
  • The piston is light-weighted to approximately 25g.
  • The weight is optimized to install with the factory crankshaft so it is not necessary to use a dummy weight to balance.


<POINT-3> ) Expertise on the Factory Parts & Reliable In-House Products
  • The 3D profile for the piston was chosen from various profile tests. The forged material exclusively for HKS and the optimal piston shape are utilized.
  • With the results of our analysis on the factory connecting rod, the durability is improved by approx 46% maintaining the balance.
  • All parts are MADE IN JAPAN (in-house product).




  HKS Stock
Bore x stroke φ95.5 X 88.4mm φ95.5 X 88.4mm
Compression ratio ε 8.7 ε 9.0
  Gasket thickness HKS t 0.8 t 0.80
Displacement (cc) 3799 3799
Piston Bore dia. φ95.5 ← same
Compression height 34.30 mm ← same
Concave portion on top 8.01 cc 4.49 cc
Material Forged (no hollow channel) Casting (with hollow channel)
Reference weight 420 g 445 g
Pin Size φ23 X 60mm φ23 X 62.5mm
Ring TOP B size 1.2 mm ← same
SEC B size 1.2 mm ← same
OIL B size 2.0 mm (3 piece) ← same
Connecting rods S. end hole size φ23 ← same
L. end hole size φ59 ← same
Center hole 165.1mm ← same
Material SCM + thermal refining Steel cast
Reference weight About 722 g About 724.6 g
Set weight dispersion Less than 1.0g
Bolt M9 X P1.0 / 14.9T ← same



■Engine Output Features (800ps Spec.)




Product Engine
Type Boring/
Full flow
Code # Price Remark
piston kit
VR38DETT 3799 φ95.5-23 Not required Not required 21003-AN009    
connecting rods
VR38DETT 3799 φ59-23 - Not required 23004-AN004   for standard stroke


Product Engine Capacity (ml) Type Boring, Honing Full Flow Modification Code No. Price Remarks
Forged Piston + H-beam Con'rod Set STEP1 VR38DETT 3799 φ95.5 - φ23 Not required Not required 21004-AN016 * Discontinued.