Forged connecting rods Toyota 1.6 12v G16E-GTS (GR Yaris) for forged pistons

The Toyota G16E-GTS engine

The G16E-GTS is the 1.6-litre turbocharged inline three-cylinder, 12-valve engine that Toyota developed for its GR range. Displacing 1,618 cc (bore 87.5 mm, stroke 89.7 mm) with a 10.5:1 compression ratio, it delivers 261 to 300 hp depending on the version and up to 390 Nm of torque. Introduced in 2020 in the GR Yaris, it became one of the most power-dense production engines the brand has ever built, with nearly 100 hp per cylinder.

This power density places exceptional loads on the reciprocating assembly: high combustion pressures, rapid revving and repeated hard use on track, in rallying or in tuned builds. As soon as boost pressure is raised or more power is targeted, the standard rods become the weak link. Forged rods then take over to withstand the increased mechanical and thermal stress without failing.

The forged connecting rods

Our forged rods for the G16E-GTS are machined from aerospace-grade 4340 steel, the reference material in motorsport. They offer far greater resistance to fatigue, bending and tensile loads than the original rods while keeping the crankshaft and piston dimensions. Supplied as a set of 3, they come in two profiles (I and H) and two centre distances (143.75 mm stock and 147.75 mm), with the matching high-strength bolts.

They cover every tuning programme: Stage 1 reliability, Stage 2 raised boost, and Stage 3 high power for track, rally, drift, drag, hillclimb or time attack. Depending on the chosen profile and bolts, the set secures the power increase up to around 250 hp per cylinder, with no compromise on reliability.

Technical specifications of the G16E-GTS forged rods

Tightening torque and stretch

The exact tightening torque and bolt stretch depend on the fasteners fitted to each rod (ARP Custom Age 625+ on the Manley rods, Carrillo WMC or CARR bolts on the Carrillo rods). They are provided in the manufacturer’s instructions supplied with the kit and must be followed precisely.

Torque tightening remains approximate because it depends on thread friction. For optimum clamping, it is recommended to measure the bolt stretch with a micrometric gauge, which is more precise than torque alone. The target values are shown on the fastener data sheet supplied with the bolts; we do not publish any torque or stretch value not confirmed by the manufacturer.

Technical guide

Forged 4340 steel: what is it?

4340 is a low-alloy steel containing nickel, chromium and molybdenum. Forging aligns the metal grain along the rod, removes internal porosity and delivers mechanical strength far above that of a cast or sintered original rod. It reaches a tensile strength of around 930 to 1,080 MPa and excellent fatigue resistance, essential when the engine gains power and revs. It is the standard for competition rods, able to absorb combustion shocks without deforming or breaking.

Connecting-rod profiles

	The I profile (I-Beam) has an I-shaped section, with a slender central web and two flanges. This geometry favours lightness and longitudinal stiffness: it limits reciprocating mass, helps the engine rev and suits power-oriented, high-rpm builds. The Manley rods offered for the G16E-GTS use this I profile.
	The H profile (H-Beam) has an H-shaped section, with two flat flanks joined by a central web. This geometry offers excellent bending and compression stiffness for a controlled weight, making it a favourite on high-torque, hard-use engines. The Carrillo rods offered for the G16E-GTS use this H profile.

How to choose your rod bolts?

	ARP 2000 is a high-strength alloy steel offering about 220,000 psi (nearly 1,517 MPa) tensile strength. It covers up to around 150 hp per cylinder and supports speeds up to 8,500 rpm. It is a robust, versatile fastener with no particular storage constraints.
	ARP L19 is a very-high-strength steel for more demanding builds: it covers up to around 200 hp per cylinder and speeds up to 10,000 rpm. Prone to oxidation, it requires oiled storage and careful assembly.
	ARP Custom Age 625+ is the top grade: it covers up to around 250 hp per cylinder and speeds beyond 10,000 rpm, with excellent fatigue resistance. This is the fastener fitted to the Manley rods offered here.

The Manley rods in this kit are fitted with ARP Custom Age 625+ bolts, while the Carrillo rods receive Carrillo’s proprietary bolts (WMC or CARR), also designed for high-performance use. The choice depends on the targeted power and maximum operating speed.

Measuring bolt stretch

Torque tightening remains an approximate method because it depends on thread friction. The most precise method is to measure the bolt-body stretch with a micrometric gauge: the bolt is tightened until it reaches the stretch specified by the fastener manufacturer. This method ensures an even preload across the three rods and maximum reliability at high rpm.

See the ARP stretch gauge

The brands offered

	Manley Performance Products, founded in 1966, is an American manufacturer renowned for its high-performance engine components: forged pistons, forged rods and crankshafts. Its 4340-steel rods, available in H and I profiles, are known for their machining quality, weight matching and reliability in severe use. For the G16E-GTS, Manley offers the I profile fitted with ARP Custom Age 625+ bolts.
	Carrillo Industries is a benchmark American manufacturer whose forged rods have equipped the most demanding competition engines for decades. Known for their strength and precision, they are supplied with Carrillo’s in-house bolts (WMC or CARR). For the G16E-GTS, Carrillo offers the H profile, particularly suited to high-torque engines.

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 Toyota G16E-GTS engine

Why is it the most cost-effective solution?

On a tuned G16E-GTS, a failing original rod often destroys the block, crankshaft and pistons. Investing in a forged rod set from the outset costs far less than an engine failure and a full rebuild. You permanently strengthen the reciprocating assembly, preserve the engine’s value and drive with peace of mind, on the road as in competition.