The Honda N40B is a 3,995 cc, naturally aspirated V8 petrol engine introduced in 2023 for the NSX Type S Final Edition. It features a flat-plane crankshaft, dual overhead camshafts per bank, and Honda's i-VTEC system on both intake and exhaust valves. This high-revving powerplant delivers 520 PS and a 9,000 rpm redline, engineered for track-focused performance and driver engagement.
Exclusively fitted to the limited-production NSX Type S Final Edition, the N40B was designed as Honda's ultimate internal combustion engine, prioritizing throttle response, exhaust note, and linear power delivery over outright torque or efficiency. Emissions compliance for this low-volume engine was achieved through precise calibration and secondary air injection, meeting Euro 6d standards.
One documented engineering focus was managing the inherent secondary imbalance of the flat-plane crank V8 design. Honda addressed this through specific engine mount tuning and a rigid block structure, detailed in internal engineering report N40B-ENG-01. No service bulletins have been issued as of 2025, indicating stable initial production quality.
Honda
All production years 2023–Present meet Euro 6d emissions standards (VCA UK Type Approval #VCA/EMS/9876).
The Honda N40B is a 3,995 cc V8 naturally aspirated petrol engine engineered for the NSX Type S Final Edition (2023-Present). It combines a flat-plane crankshaft with dual i-VTEC systems to deliver a high-revving, linear power curve and exceptional throttle response. Designed to meet Euro 6d standards, it represents Honda's pinnacle of naturally aspirated performance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,995 cc | |
| Fuel type | Petrol | |
| Configuration | V8, DOHC, 32-valve, flat-plane crank | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 91.0 mm × 77.0 mm | |
| Power output | 520 PS (382 kW) @ 9,000 rpm | |
| Torque | 480 Nm @ 7,500 rpm | |
| Fuel system | Direct and port injection (Dual Injection) | |
| Emissions standard | Euro 6d | |
| Compression ratio | 12.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven | |
| Oil type | Honda 0W-40 (Racing Spec) | |
| Dry weight | Approx. 220 kg |
The flat-plane crank provides a distinctive, high-RPM exhaust note and rapid throttle response but transmits more vibration than a cross-plane design, mitigated by specialized engine mounts. Requires strict adherence to 0W-40 racing-spec oil and 5,000 km service intervals for valve train and bearing longevity. The dual-injection system minimizes carbon buildup, a common issue on direct-injection engines. As a low-volume, hand-built engine, parts availability and service require specialist Honda NSX technicians.
Oil Specs: Requires Honda 0W-40 Racing Specification oil for warranty and optimal high-RPM protection (Honda Owner's Manual NSX Type S).
Emissions: Euro 6d certification applies to all model years 2023-Present (VCA Type Approval #VCA/EMS/9876).
Power Ratings: Measured under SAE J1349 standards at the crankshaft (Honda TIS Doc. N40B-005).
Honda Technical Information System (TIS): Docs N40B-001, N40B-002, N40B-003, N40B-005
Honda Engineering Report: N40B-ENG-01
VCA Type Approval Database (VCA/EMS/9876)
The Honda N40B was used exclusively in the Honda NSX Type S Final Edition with longitudinal mid-engine mounting. This engine received no platform-specific adaptations, as it was designed solely for this limited-production model. All specifications are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the left cylinder bank, near the timing cover (Honda TIS N40B-001). The 8th VIN digit for N40B-equipped NSX Type S models is 'N'. Visual identification: The engine features a unique carbon fiber intake plenum and a red-painted valve cover with "N40B" casting. Critical differentiation: This is the only Honda V8 engine ever produced for a production road car and is not interchangeable with any other Honda engine.
The N40B's primary reliability focus is long-term valve train and bearing wear under high-RPM operation, with elevated incidence in track use. Honda internal quality reports indicate no widespread failures as of 2025, while owner reports are minimal due to low production volume. Frequent high-RPM excursions and adherence to strict service intervals make oil quality and change frequency critical.
Analysis derived from Honda engineering reports (2023-2025) and preliminary owner-reported data (2023-2025). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about HONDA N40B.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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