Forged connecting rods Nissan VR38DETT 3.8 V6 24v biturbo (GT-R R35) 25.15 mm pin 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, and 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. This version keeps the 165.1 mm center-to-center length and adopts an enlarged 25.15 mm piston pin, intended for custom forged-piston builds.

Technical specifications of the VR38DETT forged rods (25.15 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

300M forged steel

This rod is forged from 300M, an ultra-high-strength steel derived from 4340 enriched with silicon and vanadium, chosen for the most heavily stressed engines. 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 rod gains about +19% yield strength, +8% tensile strength and +19 to +37% in fatigue, with an even greater margin for 300M on extreme engines.

Rod profiles

This rod uses Manley's I-HD 300M profile: a reinforced Heavy Duty I-beam (Pro Series I-Beam Turbo Tuff) forged from 300M, chosen for the best stiffness / weight compromise on heavily boosted VR38DETT builds. The specification table gives the steel, center-to-center length, big-end diameter and weight.

I-HD 300M profile: reinforced Heavy Duty I-beam (Manley Pro Series I-Beam Turbo Tuff) forged from 300M steel, designed for the most heavily stressed VR38DETT builds.

How to choose your rod bolts?

ARP 2000: the versatile benchmark alloy, tensile strength about 220,000 psi (1,517 MPa). Supplied here in large-diameter 7/16" for the Manley rod, it handles the high boost and high rpm of the VR38DETT, up to about 8,500 rpm. Tightening is controlled by bolt stretch, measured with a gauge.

Measuring bolt stretch

Discover the ARP stretch gauge

The featured brand

This rod is made by Manley Performance (USA), a long-standing reference in engine building, renowned for its I-HD profiles and 300M steels. It is supplied as a complete set of 6, weight-matched, with its dedicated ARP 2000 bolts (7/16").

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 (25.15 mm piston pin version), 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.