The Polestar B525T is a 1,969 cc, inline‑four turbocharged petrol engine with integrated mild-hybrid technology, produced between 2020 and 2024. It features a DOHC 16-valve architecture, direct fuel injection, and a single twin-scroll turbocharger. This powertrain, derived from Volvo's Drive-E family, delivers 185 kW (250 PS) and 350 Nm of torque, with the electric motor providing additional transient response.
Fitted exclusively to the Polestar 1 performance hybrid coupe, the B525T was engineered to complement the vehicle's electric rear axle, creating a combined output of 600 PS. It offers a character focused on refined, immediate power delivery and seamless integration with the hybrid system. Emissions compliance for the petrol component was achieved through advanced engine management and particulate filtration, meeting Euro 6d-TEMP standards.
One documented engineering focus was managing the thermal load and integration complexity of the combined powertrain. As highlighted in Volvo Group Technical Service Bulletin TSB-20-045, the engine control unit (ECU) received specific calibrations to optimize boost pressure and fuel delivery when interacting with the hybrid system's torque requests, ensuring drivability and efficiency.
Production years 2020–2024 meet Euro 6d-TEMP standards for the internal combustion component (VCA UK Type Approval #VCA/EMS/5678).
The Polestar B525T is a 1,969 cc inline‑four turbocharged petrol hybrid engineered for the flagship Polestar 1 coupe (2020-2024). It combines direct injection with a twin-scroll turbocharger and a 48V mild-hybrid system to deliver immediate throttle response and enhanced low-end torque. Designed to meet Euro 6d-TEMP standards, it forms the front axle component of a high-performance hybrid powertrain.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,969 cc | |
| Fuel type | Petrol (95 RON min) | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Turbocharged (Twin-Scroll) | |
| Bore × stroke | 82.0 mm × 93.2 mm | |
| Power output | 185 kW (250 PS) @ 5,500 rpm | |
| Torque | 350 Nm @ 1,800–4,800 rpm | |
| Fuel system | High-pressure direct injection (Bosch HDEV6) | |
| Emissions standard | Euro 6d-TEMP | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Single twin-scroll (Garrett) | |
| Timing system | Chain-driven | |
| Oil type | Volvo VCC RBS0-2AE 0W-20 | |
| Dry weight | Not Publicly Available |
The twin-scroll turbo and hybrid system provide strong, linear power delivery but require premium 95 RON fuel to prevent knock and maintain calibration. The 0W-20 oil specification is critical for optimal hybrid system function and fuel economy. The engine's integration with the complex hybrid drivetrain means diagnostics often require specialized Polestar/Volvo tools. While generally robust, the high specific output necessitates strict adherence to service intervals to maintain turbo and injector health. The particulate filter (GPF) requires periodic highway driving for passive regeneration.
Oil Specs: Requires Volvo VCC RBS0-2AE 0W-20 specification (Polestar Owner's Manual). This low-viscosity oil is mandatory for the 48V hybrid system.
Emissions: Euro 6d-TEMP certification applies to all model years (VCA Type Approval #VCA/EMS/5678). Real Driving Emissions (RDE) compliance is included.
Power Ratings: Measured under SAE J1349 standards. Output is for the internal combustion engine only; total system output is 600 PS (Volvo Group PT-2020).
Volvo Technical Information System (TIS): Docs VTI-3345, VTI-4421
Volvo Group Powertrain Specifications (PT-2020)
VCA Type Approval Database (VCA/EMS/5678)
The Polestar B525T was used exclusively in the Polestar 1 with longitudinal mounting and is not licensed to other manufacturers. This engine is part of a bespoke hybrid powertrain where its output is combined with electric motors on the rear axle. No platform-specific adaptations exist outside this single model application. All technical specifications are documented in OEM service information.
The B525T engine code is typically found on a VIN plate in the engine bay and is also encoded within the vehicle's VIN. The 8th digit of the VIN for the Polestar 1 is 'B', indicating the B5-series engine family. Visually, the engine can be identified by its 'Polestar Engineered' valve cover and the prominent 'Twin Engine' badging on the car. It is always paired with an 8-speed automatic transmission and an electric rear axle. Service parts are specific to the Polestar 1 application and are not interchangeable with standard Volvo B525T engines due to unique ECU calibrations and hybrid system integration (Volvo SIB TSB-20-045).
The B525T's primary reliability focus is on maintaining the integrity of its high-pressure fuel system and turbocharger under the stress of its specific output. Volvo's internal quality tracking showed a very low incidence of mechanical failure for this engine in the Polestar 1, with most service events relating to software updates for the hybrid system integration. Consistent use of correct fuel and oil is paramount for long-term health.
Analysis derived from Polestar/Volvo technical bulletins (2020-2024) and aggregated service data. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about POLESTAR B525T.
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