The Porsche MCY.NB is a 3,996 cc, V8 naturally aspirated petrol engine produced between 2019 and 2023. It features a 90-degree bank angle, direct fuel injection, dual overhead camshafts (DOHC), and a flat-plane crankshaft derived from motorsport applications. In standard tune it delivers 368–419 kW (500–570 PS) with torque ranging from 450–470 Nm, optimized for high-revving performance and acoustic character.
Fitted exclusively to the 911 GT3 RS and 911 Sport Classic (992 platform), the MCY.NB was engineered for track-focused performance with road legality. Emissions compliance was achieved via port-assisted direct injection, variable valve timing on intake and exhaust, and a gasoline particulate filter (GPF), ensuring adherence to Euro 6d standards from launch.
A documented concern involves excessive wear of the hydraulic chain tensioner guides under high-RPM sustained loads, potentially causing timing chain slack and misfires. This issue, highlighted in Porsche Service Information Bulletin 9830/2022, is linked to marginal surface hardness in early production tensioner rails. From 06/2022, Porsche implemented revised guides with hardened coatings.
All production years (2019–2023) meet Euro 6d standards (VCA UK Type Approval #VCA/EMS/9156).
The Porsche MCY.NB is a 3,996 cc V8 naturally aspirated petrol engineered for high-performance track applications (2019–2023). It combines a race-derived flat-plane crankshaft with port and direct injection to deliver explosive throttle response and linear power. Designed to meet Euro 6d from launch, it integrates a GPF without compromising high-RPM durability or acoustic signature.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,996 cc | |
| Fuel type | Petrol | |
| Configuration | V8, DOHC, 32-valve, 90° bank angle, flat-plane crank | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 102.0 mm × 60.8 mm | |
| Power output | 368–419 kW (500–570 PS) @ 8,500 rpm | |
| Torque | 450–470 Nm @ 6,300–6,900 rpm | |
| Fuel system | Combined port and direct injection (PFI+GDI) | |
| Emissions standard | Euro 6d | |
| Compression ratio | 13.5:1 | |
| Cooling system | Water-cooled with dual-circuit layout | |
| Turbocharger | None | |
| Timing system | Chain-driven DOHC with hydraulic tensioners | |
| Oil type | Porsche C3 (SAE 0W‑40) | |
| Dry weight | 212 kg |
The flat-plane crank enables an 8,500 rpm redline and race-inspired throttle response but demands strict adherence to RON 98 fuel and Porsche C3 oil. Oil changes every 10,000 km or 12 months are critical, especially for track use. Pre-06/2022 engines should have timing chain tensioner guides inspected per SIB 9830/2022. The GPF requires periodic high-RPM driving to prevent clogging, though carbon buildup is rare due to port injection cleaning intake valves.
Oil Specs: Requires Porsche C3 (0W‑40) specification (Porsche SIB 9150/2017). Equivalent to ACEA C3 and BMW LL‑04.
Emissions: Euro 6d certification applies to all MCY.NB models (2019–2023) (VCA Type Approval #VCA/EMS/9156). No market exceptions.
Power Ratings: Measured under ISO 1585. 419 kW output requires RON 98 fuel (Porsche TIS Doc. 992-ENG-405).
Porsche Technical Information System (TIS): Docs 992-ENG-401, 992-ENG-402, 992-ENG-405
Porsche Service Information Bulletin (SIB) 9830/2022, 9150/2017
VCA Type Approval Database (VCA/EMS/9156)
ISO 1585: Road vehicles – Engine test code
The Porsche MCY.NB was used exclusively in Porsche's 992 platform with rear-engine mounting and ultra-high-performance applications. This engine received model-specific calibration in the 911 GT3 RS versus the limited-edition 911 Sport Classic, with differences in intake resonance and exhaust valve control. From 2022, updated chain guides improved high-RPM reliability. All variants are documented in Porsche technical bulletins.
Locate the engine code stamped on the rear face of the right cylinder bank near the flywheel housing (Porsche TIS 992-ENG-410). The 7th VIN digit is ‘Y’ for MCY.NB applications. Pre-2022 engines use tensioner guide part number 9A4.110.801.00; post-2022 units use 9A4.110.801.01 with DLC coating. Visual ID: carbon-fibre reinforced valve covers with ‘GT3 RS’ or ‘Sport Classic’ plaque; individual throttle bodies visible from top. ECU is Bosch MDG9 mounted near firewall—calibration distinguishes power output and exhaust behavior.
The MCY.NB's primary reliability risk is hydraulic chain tensioner guide wear on pre-2022 builds, with elevated incidence in track-driven vehicles and sustained high-RPM usage. Porsche internal durability reports from 2022 indicated a notable rate of timing-related repairs before 30,000 km in motorsport-oriented builds, while UK DVSA records show minimal emissions-related failures due to robust GPF and catalyst integration. Oil quality and driving style make adherence to OEM oil and fuel specifications critical.
Analysis derived from Porsche technical bulletins (2019–2023) and UK DVSA failure statistics (2020–2023). Repair procedures should follow manufacturer guidelines.
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