IRP forged pistons / rods, MERCEDES M178 4.0L, AMG GT series

Italian RP (IRP) Forged Pistons & Connecting Rods kit

Forged pistons and high-performance connecting rods, engineered for high-load applications such as Stage 3 builds and dedicated racing use. The components replace OEM parts to improve reliability under sustained boost, heat, and high RPM. Sets are available in multiple bore sizes and compression ratios (selectable from the variant menu). By default, this product is supplied as a combined pistons+rods kit, but a pistons-only option is also available from the drop-down menu if preferred.

By upgrading to forged pistons and rods, enthusiasts gain a solid foundation for tuning beyond stock limits. These components are designed to handle increased cylinder pressures and provide long-term reliability in both street and track builds.

What’s included

• Forged piston set with pins, locks, and rings
• Forged H-beam connecting rod set
• Rod bolts: VIMI2500 (standard). L19 or Custom Age upgrades available separately (see Related Products).

Kit levels

Choose the specification that fits your build goals:

• Silver – Balanced performance for robust street/track use.
• Gold – Enhanced materials and machining focus for higher power targets.
• Platinum – Top-tier package aimed at extreme power and endurance requirements.

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Specifications

Compatible model	MERCEDES AMG GT / AMG GTS / AMG GTC / AMG GTR / AMG GTR PRO (4.0LTR. V8 TT)
Engine type	M178 4000cc
Stroke length	OEM mm
Pin size	22.000 mm
Rod big end diameter	55.600 mm
Rod big end width	18.85 mm
C-to-C length	153.100 mm

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IRP Forged Pistons

• High-strength forged alloy construction for detonation resistance and thermal stability
• Optimized crown and skirt geometry for controlled expansion and reduced friction
• Multiple compression ratios and oversize bores to suit different turbo and fuel strategies
• Precision-matched ring pack and full-floating wrist pins

IRP Racing connecting rods

• Forged H-beam rods designed for high cylinder pressure and RPM durability
• Cap alignment and big-end roundness controlled for consistent oil film
• VIMI2500 high-strength rod bolts as standard; L19/Custom Age optional upgrades
• Finish honed to OEM-spec bearing clearances

Fitment & ordering

These parts are model- and engine-specific. Please select bore size and compression ratio from the variant menu.
If uncertain about fitment, feel free to contact us via WhatsApp, email, or our contact form – our experts are happy to help!

Rod bolt options

Standard kits include VIMI2500 bolts. For builds targeting very high cylinder pressures, RPM, or extended endurance use, upgraded L19 or Custom Age bolts are available as an option. These are sold separately as add-ons.

Useful links & information

• IRP Main Catalog (PDF)
• Installation instructions, Pistons
• Installation instructions, Conrods

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