Forged connecting rods Mitsubishi 2.0L 16V Turbo 4B11T Lancer Evolution X for forged pistons

The Mitsubishi 4B11T engine (Lancer Evolution X)

The Mitsubishi 4B11T is a 2.0L turbocharged inline-four petrol engine, introduced in 2007 with the Lancer Evolution X. Developed under the “World Engine” alliance (Mitsubishi, Hyundai, Chrysler), it broke with its predecessor, the legendary cast-iron 4G63, by adopting a much lighter all-aluminium open-deck block. It displaces 1,998 cc (86 mm bore × 86 mm stroke), pairs DOHC 16-valve MIVEC variable valve timing with a turbocharger, and delivers roughly 280 to 360 hp from the factory depending on the market.

At the heart of the Lancer Evolution X (CZ4A chassis), the 4B11T also powers the Lancer Ralliart, a more affordable road-going version (around 241 hp). On the British FQ special editions, output climbs as high as 446 hp (FQ-440). Being an aluminium block, its bottom end calls for forged connecting rods as soon as boost pressure and engine speed rise: the original rods are then replaced with 4340 forged steel rods, usually combined with forged pistons, to make high power outputs reliable.

Forged connecting rods

Machined from high-strength 4340 steel, these forged connecting rods reinforce the bottom end as soon as power climbs. They become essential when switching to forged pistons, raising the rev limit, increasing boost pressure or gaining displacement, all situations where the stock rod reaches its limits.

Designed to withstand the heavy loads of tuned engines, whether turbocharged or supercharged, they cover every discipline, rally, drift, drag, circuit and track days, hillclimb, time attack, and support Stage 2, Stage 3 and Stage 4+ builds, right up to full competition engines.

Technical specifications of the 4B11T forged rods (23 mm pin)

Torque and bolt stretch

Manufacturers recommend the stretch-gauge method as the reference; the instructions supplied with the kit always take precedence. The torque figures given assume assembly with ARP lubricant.

Technical guide

4340 forged steel: what is it?

Connecting rod profiles

	I profile. Its slimmer central section makes the rod lighter: less inertia, freer pick-up. It is the preferred profile for modern turbo engines such as the 4B11T. Its I-HD (Heavy Duty) variant is a reinforced version built for the highest loads.
	I-3P profile (3-pocket I, Boostline). A patented design that keeps the lightness of an I-beam while adding triangulated reinforcements on the big end: its bending strength is about 60% higher than an H-beam’s. Ideal on heavily boosted engines such as a built 4B11T.
	H profile. Its “H” section delivers great stiffness and excellent resistance to both bending and compression. Slightly heavier than an I-beam, it prioritises strength: the choice for high-torque engines, large displacements and drag racing. On a torque-focused, endurance-minded 4B11T it is a safe bet, with its H-HD variant pushing the reinforcement further.

How to choose your rod bolts?

The rod bolt is among the most heavily loaded parts of the engine. The key is to match the ARP grade to the real use of the build, then to follow the assembly torque and stretch precisely.

	ARP 2000 (tensile strength around 220,000 psi, or ~1,517 MPa) is the high-performance standard. Suited to builds up to 150 hp per cylinder in 5/16″ or 200 hp per cylinder in 3/8″, and up to 8,500 rpm, it is the most common grade in circuit, track-day, drift, rally, drag and hillclimb use, valued for its strength, reliability and versatility, with no particular storage constraints.
	L19 (tensile strength around 260,000 psi, or ~1,793 MPa) is designed for engines pushed to the extreme: up to 200 hp per cylinder in 5/16″ or 250 hp per cylinder in 3/8″, and up to 10,000 rpm, under very high boost, sustained high rpm and high cylinder pressure. It is the choice for big-power builds, drag, drift, rally and circuit. Caution: sensitive to corrosion and hydrogen embrittlement, it must always be stored and fitted oiled, away from moisture.
	CA625+ (Custom Age 625+, tensile strength 260,000 to 280,000 psi, or ~1,793 to 1,931 MPa) is ARP’s premium alloy. With very high strength, it targets the most extreme builds (over 200 hp per cylinder in 5/16″ or over 250 hp per cylinder in 3/8″, beyond 10,000 rpm), while offering better resistance to atmospheric corrosion and oxidation than ARP 2000 and remaining immune to hydrogen embrittlement (without the storage constraints of L19). Ideal for the most demanding rod and cylinder-head applications.

Measuring bolt stretch

Buy the ARP stretch gauge →

The brands offered

	ZRP, a Greek brand of high-performance forged connecting rods, designed by Alex Drakos in Athens. Each rod is forged from 4340 steel, precision-machined and balanced to ±1 g to stay reliable at high rpm. Available in I or H profile with ARP 2000, L19 or Custom Age 625+ bolts, they are designed and inspected in Greece and proven in rally, on circuit and in drift.
	BOOSTLINE (Wiseco group), the forged-rod range of the American Wiseco group, a benchmark since 1941. Its patented 3-pocket design combines the stiffness of an I-beam with the strength of an H-beam. Forged from 4340 steel and machined in the United States, they ship with ARP 2000 bolts (Custom Age 625+ optional) and are built for boosted engines.
	MANLEY, an American forged-rod manufacturer since 1966. Machined from vacuum-degassed aerospace-grade 4340 steel, shot-peened and inspected one by one, its “Turbo Tuff” rods come in H and I profiles, with ARP 2000 or Custom Age 625+ bolts. A great name in engine building, from road to competition.

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 for the Mitsubishi 4B11T engine

These forged connecting rods are compatible with all vehicles fitted with the Mitsubishi 4B11T engine (2.0L 16V turbo):

OEM reference: (set of 4 rods).

Why it’s the most cost-effective solution?

When a stock bottom end fails (a broken, bent or scored rod), returning to the factory configuration means replacing the rods and, very often, the pistons damaged at the same time. The bill rises quickly for a mere repair.

For an equivalent, or even lower, budget, fitting 4340 forged steel rods together with forged pistons delivers far greater reliability and safety margin, plus genuine room to increase power. It is the route European engine builders have taken for over fifteen years.

For the same budget: more reliability, more potential, more longevity.