BMW i8’s B38K15T0 1.5L engine

BMW i8’s B38K15T0 1.5L engine.

Specifications and Compatibility

 BMW i8’s B38K15T0 1.5L engine is one of BMW’s most advanced compact power plants, engineered specifically for the brand’s flagship hybrid sports car. Designed to deliver exceptional efficiency without sacrificing performance, the B38K15T0 works in harmony with the i8’s electric motor to create a responsive, futuristic driving experience. 

As a highly specialized version of BMW’s B-series engines, this unit features reinforced internals, optimized cooling, and a unique turbocharging setup to ensure strong acceleration despite its compact size. For customers looking to restore a BMW i8 to its original performance, this engine offers unmatched precision, durability, and hybrid-ready capability.

This 1.5L turbo petrol engine is exclusively used in the BMW i8 Coupe and BMW i8 Roadster (2014–2020). Its design is tailored to work with the i8’s hybrid drivetrain, making it the only correct petrol engine for these models. While other B38 engines exist in BMW’s lineup, the B38K15T0 is uniquely tuned, calibrated, and strengthened for hybrid sports performance. This makes it essential for owners, workshops, and rebuild specialists seeking an authentic, OEM-spec replacement engine for the i8.

 Common weaknesses and Maintenance.

In terms of specifications, the B38K15T0 produces around 228 horsepower on its own, with a combined output of over 350 horsepower when paired with the i8’s electric motor. The engine displaces 1,499 cc, utilizing a lightweight aluminium block, high-precision direct injection, and a single twin-scroll turbocharger to maximize efficiency and throttle response. Its advanced cooling system, low-friction internals, and compact packaging were engineered to support high thermal loads, making it capable of handling both spirited driving and extended hybrid operation. The optimized exhaust and integrated manifold help reduce emissions and maintain quick turbo spool, contributing to the i8’s signature quiet yet powerful character.

Despite its advanced engineering, the B38K15T0 has a few common weaknesses. Some units may experience coolant system leaks, particularly at the water pump or thermostat housing, due to the high thermal cycles of hybrid operation. Carbon build-up on intake valves can develop over long mileage, typical of direct-injection engines. Additionally, oil consumption may appear if maintenance intervals are stretched or if the engine is frequently subjected to aggressive driving. 

Electric-hybrid components place added demand on the thermal management system, making cooling system health critical for engine longevity.

To maintain long-term reliability, timely oil changes with premium synthetic oil, regular coolant system inspections, and periodic intake cleaning are recommended. With proper care, the BMW i8 B38K15T0 engine delivers outstanding durability, remarkable efficiency, and the exhilarating performance expected from BMW’s futuristic hybrid sports car.