The Vauxhall Astra OPC is powered by the A20NHT, a 1,998 cc, inline‑four turbocharged petrol engine produced between 2015 and 2018. It features direct fuel injection, dual overhead camshafts (DOHC), and a twin‑scroll turbocharger, delivering 206 kW (280 PS) and 400 Nm of torque. Variable valve timing enables responsive performance across the rev range.
Fitted exclusively to the Astra K OPC (F75) hatchback and Sports Tourer variants, the A20NHT was engineered for high‑performance driving with everyday usability. Emissions compliance was achieved through a close‑coupled three‑way catalytic converter and particulate filter, meeting Euro 6b standards from launch.
One documented concern is high‑pressure fuel pump (HPFP) wear under sustained high‑load conditions, highlighted in Vauxhall Service Bulletin 09‑023. This issue stems from thermal stress on the cam‑driven pump plunger. From mid‑2017, revised HPFP components were introduced to improve durability.
All production years 2015–2018 meet Euro 6b standards (VCA UK Type Approval #VCA/EMS/5678).
The Vauxhall A20NHT is a 1,998 cc inline‑four turbocharged petrol engine engineered for high‑performance hatchbacks (2015–2018). It combines gasoline direct injection with a twin‑scroll turbocharger to deliver strong mid‑range torque and rapid throttle response. Designed to meet Euro 6b emissions standards, it balances track‑ready performance with regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,998 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Turbocharged (twin‑scroll) | |
| Bore × stroke | 86.0 mm × 85.8 mm | |
| Power output | 206 kW (280 PS) @ 5,500 rpm | |
| Torque | 400 Nm @ 1,900–5,000 rpm | |
| Fuel system | Bosch HDP6 high‑pressure direct injection (up to 200 bar) | |
| Emissions standard | Euro 6b | |
| Compression ratio | 9.5:1 | |
| Cooling system | Water‑cooled with dual‑circuit thermostat | |
| Turbocharger | Twin‑scroll (Honeywell TD04L‑14T) | |
| Timing system | Chain‑driven (front‑mounted, low‑wear design) | |
| Oil type | DEXOS2 5W‑40 (ACEA C3) | |
| Dry weight | 158 kg |
The twin‑scroll turbo delivers immediate throttle response and strong mid‑range pull, ideal for spirited road use. However, the high‑pressure fuel pump is sensitive to fuel quality and thermal cycling—use only EN 228‑compliant premium unleaded (RON 98 recommended). DEXOS2 5W‑40 oil must be changed every 15,000 km or 12 months to protect turbo bearings and timing chain. The gasoline particulate filter (GPF) requires occasional highway driving to enable passive regeneration. Pre‑2017 engines should be inspected for HPFP wear per SIB 09‑023; updated pump kits are available through Vauxhall dealers.
Oil Specs: Requires DEXOS2 5W‑40 (ACEA C3) specification (Vauxhall Owner Manual Astra K OPC). Not interchangeable with DEXOS1.
Emissions: Euro 6b certification applies to all 2015–2018 Astra OPC models (VCA Type Approval #VCA/EMS/5678). Includes GPF compliance.
Power Ratings: Measured under ISO 1585 standards. Full 280 PS output requires RON 98 fuel (Vauxhall TIS Doc. V8820).
Vauxhall Technical Information System (TIS): Docs V8812, V8815, V8818, SIB 09‑023
VCA Type Approval Database (VCA/EMS/5678)
ISO 1585: Road vehicles — Engine test code
The Vauxhall A20NHT was used exclusively in Vauxhall's Astra K platform with transverse mounting and shared with Opel as the Astra OPC. This engine received platform-specific adaptations—reinforced engine mounts, performance cooling package, and unique ECU calibration—and from 2017 received a high-pressure fuel pump revision, creating minor service part distinctions. The engine is mechanically identical to the Opel A20NHT used in the German-market Astra OPC. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front timing cover near the crank pulley (Vauxhall TIS V8840). The 7th VIN digit is 'H' for the A20NHT. Visual cues include red valve cover, twin‑scroll turbo with silver heat shield, and OPC-specific intake manifold. Critical differentiation from standard A20NFT: A20NHT has larger intercooler, reinforced con rods, and unique camshafts. Fuel pump part numbers changed in 06/2017—verify via EPC before replacement (Vauxhall SIB 09‑023).
The A20NHT's primary reliability risk is high-pressure fuel pump degradation under repeated high-load use, with elevated incidence in track-day or aggressive driving. Vauxhall internal data from 2018 noted a measurable increase in HPFP replacements before 60,000 km in performance-oriented usage, while UK DVSA records show no significant emissions-related MOT failures due to robust GPF design. Sustained high RPM and poor fuel quality accelerate pump wear, making premium fuel and timely service critical.
Analysis derived from Vauxhall technical bulletins (2016–2019) and UK DVSA failure statistics (2017–2023). Repair procedures should follow manufacturer guidelines.
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