Forged connecting rods Nissan VR38DETT 3.8 V6 24v biturbo (GT-R R35) for forged pistons

The Nissan VR38DETT engine

The VR38DETT is the 3.8 L 24-valve twin-turbo V6 that has powered the Nissan GT-R R35 since 2007. Hand-assembled in a controlled environment, it delivered 485 hp originally, rose to 570 hp, and up to 600–608 hp on NISMO versions. Its twin turbochargers, generous fuelling and low-end torque make it one of tuning's favourite platforms: exceeding 800 or even 1,000 hp at the wheels with larger turbos and proper management is common. At that level of boost and torque, the factory rods become the weak link: replacing them with forged rods is the first safeguard of a hard, lasting build.

The forged connecting rods

Drop-forged and precision-machined, these rods withstand bending, compression and fatigue loads far beyond the factory sintered rods. They cover every sporting use of the GT-R: circuit, time attack, drift, drag, rally and hillclimb. Depending on the profile and brand chosen, they support builds from Stage 2 to Stage 4 and beyond, on a VR38DETT pushed in boost, rpm and torque. Supplied as a complete set of 6, weight-matched, they preserve the balance of the rotating assembly and reliability at high rpm. All share the factory center-to-center length (165 mm) and the 23 mm piston pin of the GT-R R35.

Technical specifications of the VR38DETT forged rods (23 mm pin)

Tightening torque and stretch

On these rods, tightening is controlled by bolt stretch, measured with a gauge, rather than by torque. The stretch values below are indicative: always follow the bolt manufacturer's instructions.

Forged rods technical guide

4340, 817M40T and 300M forged steels

Most of these rods are forged from 4340 low-alloy nickel-chromium-molybdenum steel, the benchmark for high-performance rods: forged, then quenched and tempered, it keeps a continuous grain flow giving high tensile strength and excellent fatigue life. Compared with a cost-optimised sintered factory rod, a forged 4340 rod gains about +19% yield strength, +8% tensile strength and +19 to +37% in fatigue. The ZRP Pro Series references use 817M40T steel (EN24 equivalent, high-purity nickel-chromium-molybdenum), while the top Manley references are forged from 300M, an ultra-high-strength steel derived from 4340 enriched with silicon and vanadium, chosen for the most heavily stressed engines.

Rod profiles

This range comes in three profiles, all I-beam: the BoostLine I-3P, the reinforced I-HD (ZRP and Manley) and the ZRP I Pro Series. The choice depends on the power target and the type of use; the specification table gives the steel, center-to-center length, big-end diameter and weight of each reference.

	I-3P profile (BoostLine): three-pocket I-beam optimised by BoostLine to deliver maximum stiffness at controlled weight on heavily boosted engines.
	I-HD profile: reinforced Heavy Duty I-beam (Manley Pro Series I-Beam Turbo Tuff), the best weight / stiffness compromise for the vast majority of turbo builds.
	I profile (Pro Series): standard ZRP I-beam in 817M40T steel, lightened, for builds seeking a reduced reciprocating weight.

How to choose your rod bolts?

	ARP 2000: the versatile benchmark alloy, tensile strength about 220,000 psi (1,517 MPa). Offered here in 3/8" (ZRP and BoostLine rods) and large-diameter 7/16" (Manley rods), it covers turbo builds up to about 200 hp per cylinder in 3/8", more in 7/16", at speeds reaching 8,500 rpm.
	ARP L19: a higher-grade alloy (≈ 260,000 psi / 1,793 MPa) for high-boost, high-rpm engines, up to about 250 hp per cylinder in 3/8". Sensitive to corrosion and hydrogen, it must be oiled and stored with care.
	ARP Custom Age 625+: the highest-performing alloy in the range (≈ 260,000 to 280,000 psi), immune to corrosion and hydrogen embrittlement, with no storage constraints. Reserved for the most extreme engines, it equips the BoostLine rods here in 3/8".

Measuring bolt stretch

Discover the ARP stretch gauge

Available brands

This range brings together three renowned makers of forged competition rods: ZRP (precision-machined rods, weight-matched to ± 1 g), BoostLine (patented I-3P profile, specialist in heavily boosted engines) and Manley Performance (USA, a long-standing tuning reference, I-HD and 300M profiles). Each reference is supplied as a complete set of 6, weight-matched, with its dedicated ARP bolts.

ZRP

Boostline

Manley

Glossary

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

Vehicle compatibility of the Nissan VR38DETT engine

Rods compatible with the Nissan VR38DETT engine (23 mm piston pin), which powers every version of the Nissan GT-R R35:

Why it is the most economical solution

A set of forged rods costs far less than an engine failure: on a boosted VR38DETT, an original rod that lets go takes out the block, the crankshaft and often a cylinder head. By fitting weight-matched forged rods from the start, you make your GT-R reliable for the long term and avoid a full rebuild, for a negligible extra cost compared with the price of a new engine.