Product successfully added to your shopping cart
Quantity
Total
There are 0 items in your cart. There is 1 item in your cart.
Total products
Total shipping To be determined
Total
3.5L 24v - S38B36
Manufacturers
3.5L 24v - S38B36
Warning: Last items in stock!
New product
Set of 6 forged 4340 steel connecting rods for BMW M5 E34 (S38B36 engine, 315 hp).
The BMW S38B36 (commonly called the “S38”) is BMW Motorsport's naturally aspirated 3.6L 24-valve inline-six, a direct descendant of the M88 from the M1. It combines a cast-iron block, an aluminium twin-cam four-valve head and six individual throttle bodies. It displaces 3,535 cc (bore 93.4 mm × stroke 86 mm), produces 315 hp and was hand-assembled by the M division from 1988 to 1992.
Fitted to the BMW M5 E34, the S38B36 makes it one of the fastest saloons of its era. Reputedly robust, it nonetheless becomes sensitive as soon as you raise compression, the rev limit or consider forced induction: the original rods are then replaced with reinforced forged 4340-steel rods, combined with forged pistons, to secure higher power.
Machined from high-strength forged 4340 steel, these rods reinforce the S38B36's bottom end as soon as you go beyond stock power. They become essential with forged pistons, raised compression or higher revs, where the standard rod eventually bends or breaks.
Built for competition, they absorb the repeated loads of circuit, rally, hillclimb and historic motorsport, and comfortably support Stage 2 to Stage 4+ builds of an M inline-six.
| Reference | Brand | Profile | Bolts | Pin diameter OEM 22 mm | Small-end width | Big-end diameter OEM 52 mm | Big-end width | Center-to-center OEM 144 mm | Weight per rod |
|---|---|---|---|---|---|---|---|---|---|
| R-BMW-001-I-6 | ZRP | I | ARP 2000-3/8"-38mm | 22 mm | 52 mm | 23.9 mm | 144 mm | 566 g | |
| R-BMW-001-I-6-L19 | ZRP | I | ARP L19-3/8"-38mm | 22 mm | 52 mm | 23.9 mm | 144 mm | 566 g |
| Rod | Bolts | Torque | Recommended stretch |
|---|---|---|---|
| ZRP (R-BMW-001-I-6) | ARP 2000 | 61 N·m | 0.140 – 0.152 mm |
| ZRP (R-BMW-001-I-6-L19) | ARP L19 | 67.8 N·m | 0.152 – 0.165 mm |
Manufacturers recommend the stretch-gauge method as the reference: the instructions supplied with the kit always take precedence. The torque figures correspond to assembly with ARP lubricant.
| 4340 is a low-alloy nickel-chromium-molybdenum steel valued in aerospace and motorsport. Forged then quenched and tempered, it combines a high yield strength, excellent fatigue endurance and good ductility. Against the sintered metal fitted as standard, forged 4340 gains around 19% in yield strength, nearly 8% in tensile strength and 19 to 37% in fatigue life: the go-to material when revs and cylinder pressure climb. |
 | I-Beam. Its slimmer central section lightens the rod and cuts inertia: the engine revs more freely. It is the profile chosen for the S38B36, suited to a naturally aspirated inline-six that lives at high revs. |
The rod bolt is one of the most heavily loaded parts of the engine. Choosing well means matching the grade to the actual use, then strictly respecting the assembly torque and stretch.
 | ARP 2000 (tensile strength ~220,000 psi, i.e. ~1,517 MPa): the high-performance standard. It covers the vast majority of road and track builds with no storage constraint — the versatile choice for a tuned S38B36. |
 | ARP L19 (tensile strength ~260,000 psi, i.e. ~1,793 MPa): for the most extreme builds, sustained high revs and heavy loads. Sensitive to corrosion and hydrogen embrittlement, it must be stored and fitted oiled, away from moisture. |
| In addition to torque tightening, measuring stretch reflects each bolt's true tension, regardless of friction. A dedicated gauge lets you respect the manufacturer's value and achieve even clamping across all six rods. |
 | ZRP is a Greek brand of high-performance forged connecting rods, produced by Drakos Engineering in Athens. Each rod is forged from 4340 steel, carefully machined and balanced to ±1 g to handle high revs. For the S38B36 they are offered as an I-beam with ARP 2000 or ARP L19 bolts. |
 | 1) Small end 2) Small-end diameter 3) Rod beam 4) Rod bolt 5) Big end 6) Rod nut / bolt 7) Rod cap 8) Big-end diameter 9) Center-to-center |
These forged connecting rods are compatible with all vehicles fitted with the BMW S38B36 engine (3.0L 24V twin-turbo):
| Brand | Model (chassis) | Engine code | Power | Years |
|---|---|---|---|---|
| BMW | M5 (E34) | S38B36 | 315 hp | 1988–1992 |
OEM reference: 11 24 1 307 653 (set of 6 rods).
When the original bottom end gives out (a broken, bent or scored rod), returning the M5 to factory spec often means replacing rods and pistons together, both damaged at once. The bill climbs fast, just to get back to square one.
For a comparable, even lower budget, switching to forged 4340 rods and forged pistons brings far greater reliability and safety margin, with real room to grow. It has been the European tuners' reflex for over fifteen years.
For the same budget: more reliability, more potential, more longevity.
