The ZRP I-shaped forged connecting rods for the BMW M5 E34 with the S38B36 engine are designed for engine upgrades requiring high mechanical resistance and rigidity. Manufactured from high-strength 4340 steel, they have a center distance of 144 mm and accommodate 22 mm gudgeon pins.
Their AMPCO 18 connecting rod small ends feature a radial groove that serves as an oil reservoir. The set of 6 connecting rods (R-BMW-001-I-6) includes 3/8" ARP2000 fasteners, ARP mounting lubricant, and instructions.
Technical Specifications
- Brand: ZRP
- Manufacturer Part Number: R-BMW-001-I-6
- Application: BMW M5 E34
- Engine Code: S38B36
- Profile: I-beam
- Material: 4340 forged steel
- Center-to-center length: 144.00 mm
- Gudgeon pin diameter: 22.00 mm
- Connecting rod bush diameter: 52.00 mm
- Connecting rod top end width: 23.90 mm
- Connecting rod small end rings: AMPCO 18
- Fasteners: 3/8" ARP2000
- Rated tensile resistance of fasteners: 220,000 psi
- Specified weight per connecting rod: 566 g
- Weight matching: ± 1 g
- Packaging: set of 6 connecting rods
Design and Manufacturing
- Separately forged body and cap: two-piece construction.
- I-beam profile: geometry designed for rigidity.
- Double-ribbed connecting rodcaps with humps: reinforcement of the connecting rod top end.
- Centering sockets: precise repositioning of the cap during reassembly.
- Grooves on the bearing flanks: weight reduction in the affected areas.
- Multi-stage heat treatments: resistance, dimensional stability, and fatigue resistance.
- Shotpeening: improved fatigue resistance.
- Magnetic particle inspection: detection of defects in forged parts.
- CNC machining: specified precision up to 0.0002", or approximately 0.005 mm.
- Center distance tolerance: less than 0.001", or 0.0254 mm.
- Bending and torsion testing: verification of geometry.
- Finite element analysis: computer-aided stress analysis.
Mounting on a BMW S38B36 engine
Before assembly, verify that the pistons, shafts, bearings, and crankshaft journals match the sizes of the connecting rods. Check the operating clearances and clearance between moving parts. Follow the oiling and tightening specifications specific to the supplied ARP2000 fasteners.
Key Features
- 4340 forged steel and I-beam profile.
- 144 mm center distance and 22 mm gudgeon pin diameter.
- AMPCO 18 piston rings with oil reservoir.
- ARP2000 fasteners included.
- Set of 6 connecting rods matched in weight to within ± 1 g.
