The I-Beam “Heavy Duty” series connecting rods for VW R32/R36 engines are designed for high horsepower and boost applications. Constructed from 4340 high tensile steel, these rods feature a specially optimized shape for enhanced performance and durability. The bushings are made from AMPCO 18 material, providing excellent wear and fatigue resistance, with a radial groove that acts as an oil reservoir. Each rod undergoes shot peening to relieve stress and is multi-stage heat treated to increase rigidity. Tight tolerances in the production process ensure a perfect fit while optimizing oil clearances, with controlled bend and twist. Each rod is equipped with 3/8 ARP 2000 cap fasteners rated at 220,000 psi, with an optional upgrade to ARP L19 material rated at 260,000 psi. The complete kit includes ARP moly and full fitting instructions.

Additional Machining Processes

• Dowel sleeves for perfect fit and accurate re-assembling
• Lipped cap relief for improved big-end integrity in extreme applications
• Grooves in thrust face for weight reduction

Technical Features of ZRP Connecting Rods

• Two-piece forging for great strength
• I-beam shape for extra rigidity
• Shot peening for improved fatigue life
• Magnaflux inspection ensures consistency of the forged material
• Double ribbed caps for added support
• Multi-stage heat treatment for maximum strength, dimensional stability, and fatigue life
• CNC machining for superior tolerances, precise to 0.0002″
• Center-to-center maintained under 0.001″ tolerance
• Finite Element Analysis (FEA) for computer-generated stress analysis of connecting rods
• Optimal balancing for weight-matched sets of ± 1 gram