ZRP Connecting Rods for Honda B18A / B18B / B20 HD Series

The "Heavy Duty" I-Beam connecting rods for Honda B18A, B18B, and B20 engines are designed for high-horsepower/forced-induction applications. Manufactured from the highest quality 4340 high-tensile steel, they feature a specially optimized shape for high performance and extreme durability. The bushings are made from AMPCO 18 material, which offers excellent wear and fatigue resistance, and feature a radial groove that acts as an oil reservoir. They undergo shot-peening to relieve material stress and a multi-stage heat treatment to increase their rigidity. Strict tolerances in the production process ensure a perfect fit and optimize oil clearances. Bending and twisting are strictly controlled. Each connecting rod includes 3/8" ARP 2000 head bolts with a tensile strength of 220,000 psi. Optionally, ARP L19 material with a tensile strength of 260,000 psi can be purchased. The complete kit includes ARP Moly lubricant and full assembly instructions.

Additional machining processes

Alignment dowels for a perfect fit and precise reassembly

Flanged cap relief for greater big-end integrity in extreme applications

Grooves on the thrust face to reduce weight

Technical features of ZRP connecting rods

I-beam shape for greater rigidity

Two-piece forging for high strength

Shot-peened for increased fatigue resistance

Magnaflux inspection ensures the consistency of the forged material meets our high-quality standards

Dual-ribbed caps for extra support

Multi-stage heat treatment for maximum strength, dimensional stability, and fatigue resistance

CNC machined for superior tolerances, with precision down to 0.0002"

Center-to-center distance is maintained within a tolerance of 0.001"

Finite Element Analysis (FEA): computer-generated stress analysis of the connecting rods

Optimal balancing for sets weight-matched to ± 1 gram