The Alfa Romeo AR 66301 is a 2,891 cc, 90° V6 naturally aspirated petrol engine produced between 2020 and 2025. It is derived from the Ferrari F154 engine family, co-developed with Maserati and adapted for longitudinal mounting in Alfa Romeo's high-performance models. Featuring direct fuel injection, variable valve timing, and a flat-plane crankshaft, it delivers 375 kW (510 PS) and 600 Nm of torque. This engine was engineered for high-revving performance and track-capable dynamics.
Fitted exclusively to the Alfa Romeo Giulia Quadrifoglio (952) and Stelvio Quadrifoglio (956), the AR 66301 serves as the flagship naturally aspirated powerplant in select performance variants. Its design emphasizes lightweight construction, rapid throttle response, and motorsport-derived engineering, achieving Euro 6d-FULL compliance through close-coupled three-way catalytic converters and dual lambda sensors.
One documented engineering enhancement is the integration of dry-sump lubrication, as specified in Alfa Romeo Technical Bulletin 57 00 01 24. This upgrade improves oil control during high-lateral-g cornering and sustained track use. Additionally, forged titanium connecting rods and a flat-plane crankshaft were implemented to reduce rotating mass and enhance high-RPM responsiveness.
Production years 2020–2025 meet Euro 6d-FULL emissions standards (VCA UK Type Approval #VCA/EMS/7892).
The Alfa Romeo AR 66301 is a 2,891 cc V6 naturally aspirated petrol engine designed for high-performance applications (2020–2025). It combines Ferrari-derived architecture with advanced direct injection and high-RPM tuning to deliver 510 PS and 600 Nm. Built for track and spirited road use, it meets Euro 6d-FULL standards while maintaining sharp throttle response and high-RPM power delivery.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,891 cc | |
| Fuel type | Petrol | |
| Configuration | 90° V6, DOHC, 24-valve with variable valve timing | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.0 mm × 82.0 mm | |
| Power output | 375 kW (510 PS) @ 7,000 rpm | |
| Torque | 600 Nm @ 3,000–5,500 rpm | |
| Fuel system | Direct injection (up to 200 bar) | |
| Emissions standard | Euro 6d-FULL | |
| Compression ratio | 11.3:1 | |
| Cooling system | Water-cooled, dual-circuit with electric thermostat | |
| Valvetrain | DOHC, 4 valves per cylinder, variable valve timing | |
| Timing system | Chain-driven (non-interference design) | |
| Oil type | Fiat 9.55535-S3 MOPAR S5 0W-40 | |
| Dry weight | 162 kg |
The flat-plane crankshaft enables high-RPM responsiveness ideal for track use but requires strict adherence to 15,000 km oil service intervals using MOPAR S5 0W-40 to prevent bearing degradation and oil starvation. The dry-sump system prevents oil surge during high-G cornering but demands precise oil volume management. Aggressive driving without cooldown increases thermal stress; front-mounted oil coolers help mitigate this. Direct injection necessitates periodic intake valve cleaning. The non-interference valvetrain reduces risk of catastrophic damage in case of timing chain failure. OBD-II monitoring should include catalyst efficiency and knock control stability.
Oil Specs: Requires Fiat 9.55535-S3 / MOPAR S5 0W-40 specification (Alfa Romeo SIB 57 00 01 24). Supersedes ACEA C4.
Emissions: Euro 6d-FULL certification applies to all models 2020–2025 (VCA Type Approval #VCA/EMS/7892). No market-specific variants outside EU.
Power Ratings: Measured under UN ECE Regulation 85. Output achieved with RON 98 fuel (Alfa Romeo TIS Doc. A66301-TEST1).
Alfa Romeo Technical Information System (TIS): Docs A66301-TECH1, A66301-TECH2, SIB 57 00 01 24
VCA Type Approval Database (VCA/EMS/7892)
UN ECE Regulation 85: Power Measurement Standards
The Alfa Romeo AR 66301 was used exclusively in Alfa Romeo's 952/956 platform high-performance variants with longitudinal mounting. This engine received model-specific calibrations, including track-tuned throttle mapping in the Quadrifoglio trims and enhanced cooling systems for circuit use. From 2020, it featured dry-sump lubrication and forged titanium connecting rods per Technical Bulletin 57 00 01 24, distinguishing it from turbocharged variants. All specifications are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the rear-facing side of the engine block, near the bellhousing (Alfa Romeo TIS A66301-ID1). The 8th VIN digit indicates engine type ('V' for V6 petrol units). Quadrifoglio models feature a red-painted cam cover and a prominent "6C" badge on the intake manifold. Critical differentiation from AR 66201: AR 66301 has a naturally aspirated configuration with no turbochargers and uses dry-sump lubrication. Service parts are not interchangeable with turbocharged engines due to fundamental architecture differences (Alfa Romeo SIB 57 00 01 24).
The AR 66301's primary reliability risk is intake valve carbon buildup under mixed driving conditions, with elevated incidence in vehicles with frequent short trips. Internal Alfa Romeo field reports from 2021 indicated a measurable share of units requiring intake cleaning before 70,000 km, while VCA emissions data shows increased catalyst degradation in vehicles with delayed maintenance. Aggressive driving without cooldown cycles increases thermal stress, making oil quality and cooling system integrity critical.
Analysis derived from Alfa Romeo technical bulletins (2020-2025) and UK DVSA failure statistics (2021-2024). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about ALFA-ROMEO AR66301.
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