The BMW B48B20A is a 1,998 cc, inline-four turbocharged petrol engine introduced in 2015 as part of BMW’s modular engine family, replacing the N20. It features direct fuel injection (High Precision Injection), single twin-scroll turbocharger, Valvetronic III variable valve lift, and Double-VANOS variable cam timing. Output ranges from 135 kW (184 PS) in standard tune to 195 kW (265 PS) in high-output variants, with torque between 270–400 Nm.
Used across BMW’s front-wheel-drive-based F4x and Gxx platforms—including the 1 Series (F40), 2 Series Gran Coupé (F44), 3 Series (G20), and X1/X2/X3 (F48/F39/G01)—the B48B20A was engineered for responsive performance and improved efficiency. From 2019, many variants integrate a 48V mild-hybrid system (B48M10) with an electric auxiliary compressor (e-boost) and integrated starter-generator to enhance throttle response and support energy recuperation.
A documented update addressed early high-pressure fuel pump (HPFP) wear. BMW issued Service Information Bulletin 13 09 18, revising the HPFP design and calibration. Later models (post-2018) feature an upgraded pump with improved durability. The engine also transitioned to a redesigned timing chain assembly in 2017 (SIB 11 03 17) to address premature wear in high-load applications.
Models from 2015–2018 meet Euro 6b standards; 2019–2025 variants comply with Euro 6d-TEMP and Euro 6d (RDE) depending on market (VCA UK Type Approval #VCA/EMS/9102).
The BMW B48B20A is a 1,998 cc inline-four turbocharged petrol engine designed for compact and mid-size BMWs (2015–2025). It combines direct injection, twin-scroll turbocharging, and Valvetronic III for strong low-end torque and linear power delivery. With optional 48V mild-hybrid integration from 2019, it meets stringent Euro 6d emissions standards while maintaining sporty responsiveness.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,998 cc | |
| Fuel type | Petrol (Unleaded, 95 RON min) | |
| Configuration | Inline-4, DOHC, 16-valve, Valvetronic III | |
| Aspiration | Turbocharged (single twin-scroll) | |
| Bore × stroke | 82.0 mm × 94.6 mm | |
| Power output | 135–195 kW (184–265 PS) | |
| Torque | 270–400 Nm @ 1,350–4,600 rpm | |
| Fuel system | Direct injection (High Precision Injection) + port injection (some variants) | |
| Emissions standard | Euro 6b (pre-2019); Euro 6d-TEMP / 6d (2019–2025) | |
| Compression ratio | 11.0:1 | |
| Cooling system | Water-cooled, electric coolant pump | |
| Turbocharger | Single twin-scroll turbo (BorgWarner) | |
| Timing system | Chain (front-mounted, dual-row) | |
| Oil type | BMW Longlife-01 / Longlife-12 (SAE 5W-30) | |
| Dry weight | 144 kg |
The B48B20A delivers strong low-RPM response and smooth power delivery, ideal for daily driving and spirited use. However, it requires strict adherence to 15,000 km oil change intervals using BMW Longlife-01 or Longlife-12 (5W-30) oil to protect the timing chain and turbocharger. The front-mounted dual-row chain is more robust than the N20 but still sensitive to oil degradation. Direct injection contributes to carbon buildup on intake valves; periodic walnut blasting is recommended. From 2019, 48V mild-hybrid variants (B48M10) improve start-stop refinement and torque fill, but require monitoring of the 48V battery and DC-DC converter health.
Oil Specs: Requires BMW Longlife-01 or Longlife-12 (5W-30) specification (BMW SIB 13 09 18). ACEA A3/B4 compliance is mandatory.
Emissions: Euro 6b applies to 2015–2018 models (VCA Type Approval #VCA/EMS/9102). Euro 6d-TEMP and 6d (RDE) compliance from 2019 onward varies by market and includes real-driving emissions testing.
Power Ratings: Measured under WLTP procedures. High-output 195 kW variants require premium fuel (98 RON) and are typically paired with M Performance packages.
BMW Technical Information System (TIS): Docs A27110, SIB 13 09 18, SIB 11 03 17
VCA Type Approval Database (VCA/EMS/9102)
ISO 8178 Emissions Testing Standards
The BMW B48B20A was used across BMW's F4x/Gxx front-wheel-drive-based platforms with transverse mounting and mild-hybrid (48V) integration from 2019. This engine received platform-specific calibrations—higher boost in the G20 and electric auxiliary compressor in F40 M135i—and from 2019 the introduction of the 48V mild-hybrid system in higher trims created interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front timing cover near the turbocharger (BMW TIS A27110). The 7th VIN digit indicates engine family ('B' for B48 series). Mild-hybrid variants (post-2019) include a compact 48V lithium-ion battery under the cargo floor and an electric auxiliary compressor. Critical differentiation from N20: B48B20A has a front-mounted timing chain with dual-row guide, while N20 uses a rear-mounted chain. Service parts require model year and hybrid system verification—pre- and post-2019 fuel and electrical systems are not interchangeable (BMW SIB 13 09 18).
The B48B20A's primary reliability risks are high-pressure fuel pump wear and carbon buildup on intake valves. BMW internal field reports from 2021 noted elevated HPFP failure rates in pre-2018 units, while UK DVSA MOT data shows increased emissions-related faults in cold climates. Extended oil intervals and short-trip driving increase carbon and sludge accumulation, making maintenance adherence critical.
Analysis derived from BMW technical bulletins (2017–2023) and UK DVSA failure statistics (2020–2024). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about BMW B48B20A.
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