The Honda P28A is a 2,799 cc, inline‑six turbocharged petrol engine produced from 2021 to present. It features direct injection, a twin-scroll turbocharger, and dual overhead camshafts (DOHC) with VTEC. This powerplant delivers 250 kW (340 PS) and 450 Nm of torque, with VTEC enabling a broad, responsive powerband for dynamic performance.
Fitted exclusively to the second-generation NSX Type S and select Acura TLX Type S models in North America, the P28A was engineered for high-revving performance, track capability, and refined road manners. Emissions compliance was achieved through gasoline particulate filtration (GPF) and advanced engine management, allowing it to meet stringent Euro 6d and EPA Tier 3 standards.
One documented concern is potential oil starvation under extreme lateral G-forces during track use, which can trigger low oil pressure warnings. This issue, referenced in Honda Service Bulletin 22-008, is addressed by a revised baffle system for high-performance applications. The engine also requires strict adherence to break-in procedures to ensure long-term turbocharger health.
Honda
All production years (2021–Present) meet Euro 6d or EPA Tier 3 standards depending on market (VCA UK Type Approval #VCA/HON/8899, EPA Cert. #A-HON-21-001).
The Honda P28A is a 2,799 cc inline‑six turbocharged petrol engineered for high-performance sports cars and sedans (2021-Present). It combines direct fuel injection with VTEC variable valve timing and a twin-scroll turbo to deliver exceptional specific output and a linear, high-revving power curve. Designed to meet Euro 6d/EPA Tier 3 emissions standards, it balances track-ready performance with road legality.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,799 cc | |
| Fuel type | Petrol (Gasoline) | |
| Configuration | Inline‑6, DOHC, 24‑valve | |
| Aspiration | Turbocharged (Twin-scroll) | |
| Bore × stroke | 86.0 mm × 80.0 mm | |
| Power output | 250 kW (340 PS) @ 6,500 rpm | |
| Torque | 450 Nm @ 2,500–5,000 rpm | |
| Fuel system | Direct Injection (DI) | |
| Emissions standard | Euro 6d / EPA Tier 3 | |
| Compression ratio | 10.2:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Garrett GTX3584R twin-scroll turbo | |
| Timing system | Chain-driven | |
| Oil type | Honda 0W-40 (High-Performance Spec) | |
| Dry weight | Approx. 185 kg |
The twin-scroll turbo and VTEC system provide exceptional throttle response and a high-revving character, ideal for spirited driving but demanding premium unleaded (98 RON) for optimal performance and to prevent knock. The 0W-40 oil specification is critical for turbo bearing protection and VTEC solenoid function under high stress. Track use requires the revised oil pan baffle per Honda SIB 22-008 to prevent oil starvation. The GPF requires occasional highway driving to regenerate; frequent short trips can trigger warning lights. Strict adherence to the 1,000 km break-in procedure is mandatory to ensure turbo longevity.
Oil Specs: Requires Honda 0W-40 High-Performance specification (Honda SM P28A-SM). No substitutes are approved for track use.
Emissions: Euro 6d / EPA Tier 3 certification applies to all models (VCA #VCA/HON/8899, EPA #A-HON-21-001).
Power Ratings: Measured under SAE J1349 standards. Peak output requires 98 RON fuel (Honda TSB 22-008).
Honda Technical Information System: Docs H-P28A-001, SM P28A-SM, TSB 22-008
VCA Type Approval Database (VCA/HON/8899)
US EPA Certification Database (Cert. #A-HON-21-001)
SAE International: J1349 Engine Power Certification Standards
The Honda P28A was developed for Honda's high-performance NSX platform and adapted for the Acura TLX Type S with longitudinal mounting. This engine received minor platform-specific adaptations for cooling and intake routing. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block, near the crankshaft pulley (Honda SM P28A-SM). The 8th VIN digit for NSX Type S is 'Y'; for TLX Type S, it is 'S'. Visually, the P28A is identifiable by its red valve cover (NSX) or black (TLX), and the prominent twin-scroll turbocharger on the exhaust side. Critical differentiation from other Honda engines: The P28A is Honda's only modern production inline-six. Software and some sensors are not interchangeable between NSX and TLX applications due to different ECU calibrations (Honda TSB 22-008).
The P28A's primary reliability risk is oil starvation under extreme track conditions, with elevated incidence in vehicles used for high-G cornering without the revised baffle. Honda service data indicates this is a design-specific risk for early-production track-focused units, while owner reports frequently cite issues after aggressive circuit use. Extended high-G operation without the baffle upgrade increases risk, making the SIB 22-008 modification critical for track use.
Analysis derived from Honda technical bulletins (2021-Present) and aggregated service data. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about HONDA P28A.
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