The I-Beam Connecting rods for BMW S58B30 are built from the finest raw materials, 4340 high tensile steel with a specially optimized shape for high performance and extreme durability. These feature “straight cut” pin ends for increased durability, so they can only be used with aftermarket pistons. The bushings are made from AMPCO 18 material for excellent wear and fatigue resistance and have radial grooves acting as an oil reservoir. They are shot peened to relieve stress from the material and multi-stage heat treated to increase rigidity. The tight tolerances in the production process ensure a perfect fitment while optimizing the oil clearances. Bend and twist are tightly controlled. Each rod includes ARP 2000 cap fasteners rated at 220,000psi, optional ARP L19 material 260.00psi available as an upgrade, and the whole kit is supplied with ARP moly and full fitting instructions.

Additional machining processes

• “Straight Cut” Pin End – Suitable for aftermarket pistons
• Dowel sleeves for perfect fit and accurate re-assembling
• Lipped Cap Relief for improved big-end integrity at extreme application
• Grooves in Thrust Face for weight reduction

Technical Features of ZRP Connecting Rods

• I-Beam Shape for extra rigidity
• Two-Piece forging for great strength
• Shot Peening for improved fatigue life
• Magnaflux Inspection guarantees that the consistency of the forged material meets our high-quality standard
• Double ribbed caps for added support
• Multi Stage Heat Treatment for maximum strength, dimensional stability, and fatigue life.
• CNC machining for superior tolerances, precise as much as 0.0002″
• Center to center is maintained under .001″ tolerance
• Finite Element Analysis (FEA) Computer generated stress analysis of con rods
• Optimal balancing for weight matched sets of ± 1gram