Alternator BMW F87 M2 F80 M3 F82 F83 M4 S55 Engine Generator 250A Denso 7848603

Alternator BMW F87 M2 F80 M3 F82 F83 M4 S55 Engine Generator 250A is an original component from the Alternators and generators group, designed for BMW sports models with the S55 petrol engine. It ensures stable power supply for all electrical consumers and proper battery charging even during dynamic driving.

Specifications and technical data

• SKU: 7848603-1
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7848603
• Substitutable numbers: 7848603, 12317848603
• Fuel type: Petrol
• Category: Alternators & Generators

Purpose and compatibility

The presented generator is designed for installation in BMW F87 M2, F80 M3, and F82/F83 M4 models with the S55 petrol engine. The alternator's construction is adapted to the high electrical loads typical of M versions, including extensive onboard electronics, safety systems, and driver assistance systems.

Thanks to its factory origin, the alternator maintains full compatibility with the vehicle's electrical system, engine control units, and factory charging parameters. Proper fitment of mounts and connectors allows for installation without the need to modify wiring or brackets.

Operating parameters and technical characteristics

The 250A capacity alternator has been engineered for the high energy demands of BMW sports models. Such high current output enables stable power supply for:

• engine control systems and M Performance systems,
• advanced safety and driver assistance systems,
• extensive multimedia and comfort systems,
• additional consumers installed in track-oriented or tuned vehicles.

The generator works with the S55 petrol engine system, ensuring appropriate charging characteristics across the full RPM range – from city driving to intensive use at high revs.

Application in the S55 engine and benefits of installation

In the S55 unit, the alternator is responsible not only for charging the battery but also for the stability of all electronic systems that directly impact performance and safety. A functional generator:

• reduces the risk of voltage drops under high electrical load,
• supports the proper operation of boost and injection control systems,
• provides power reserves for additional consumers (e.g., telemetry, sports cooling systems, or track lighting).

For BMW M2, M3, and M4 users, replacing the alternator with a functional OEM component is crucial for maintaining stable engine operating parameters and repeatable performance in both road and track conditions.

Condition, verification, and part selection

The offered alternator is a used component, which in practice represents a favorable compromise between cost and maintaining BMW factory specifications. Before installation, it is recommended to perform a standard verification of the vehicle's charging system (condition of the battery, ground cables, and drive belt) to fully utilize the generator's potential.

When selecting an alternator for a specific BMW M vehicle, it is worth paying attention to compatibility with the S55 engine and fuel type (petrol), as well as the body version (F87, F80, F82, F83). This ensures that the installation proceeds smoothly and the charging system maintains the parameters specified by the manufacturer.

BMW alternators and generators – expansion and service

If you are planning a comprehensive repair or upgrade of the engine area in your BMW and need other components from the same group, such as additional generators, alternators with different capacities, or compatible mounting elements, check the available parts in the BMW alternators and generators category.

For a comparison of engine characteristics and how high-performance engines affect the load on the charging system, the material comparing RS sports versions with standard models may be helpful – more information can be found in the article Audi RS vs other models – what is hidden under the hood and chassis?.