Audi RS4 B7 8E Bare Engine BNS 4.2 FSI 420HP Petrol 99k miles, WARRANTY

Warranty and technical condition of the part

The engine is sold with a 90-day warranty.

The power unit was tested before removal and is in full working order.

Listing details

The offer applies to a bare engine.

The engine is sold without accessories (e.g. alternator, starter motor, manifolds, injectors, turbocharger, etc.).

Audi RS4 B7 8E Bare Engine BNS 4.2 FSI 420HP Petrol 99k miles, WARRANTY is a factory-spec V8 powertrain designed for the Audi RS4 B7 generation models. It offers the characteristic combination of high revs, strong torque, and precise throttle response typical of this version, serving as a solid foundation for professional repair or replacement of an existing engine. By maintaining the original specifications, it is an attractive option for users seeking compatibility with factory drivetrain requirements.

Specifications and technical data

• SKU: 079100031K
• Mark: Audi
• Condition: Used
• OEM Part Number: 079100031K
• Substitutable numbers: 079100031K, 079 100 031 K, 079100031KX, 079 100 031 KX
• Fuel type: Petrol
• Number of cylinders: 8
• Part type: Engine Long Block
• Category: Engines
• Engine code: BNS
• Mileage: 99 000

Technical characteristics of the BNS 4.2 FSI unit

The presented engine belongs to the Engines category and is designed for petrol operation in a V8 configuration. The BNS code denotes a naturally aspirated 4.2 FSI unit, known for its high maximum power and linear torque delivery across a wide rev range. The use of FSI direct fuel injection allows for precise control of the combustion process, which translates into dynamic load response and stable operation across the entire RPM range.

The "bare" engine version is a short block prepared for further assembly with accessories compatible with the specific configuration of an Audi RS4 B7. This solution is particularly beneficial for advanced repairs when the previous unit has suffered severe mechanical damage or requires comprehensive regeneration of the block and heads.

Application in Audi RS4 B7 8E

The BNS 4.2 FSI unit is dedicated to the sports version of the Audi RS4 B7 generation, where it is responsible for the characteristic high-revving handling and the distinctly sporty nature of the car. The V8 construction ensures appropriate refinement, and the naturally aspirated configuration facilitates predictable behavior during dynamic track and road driving. For users who want to maintain the original character of the RS4, using a factory engine with this code is crucial from the perspective of mechanical and electronic compatibility.

The unit's mileage allows for an assessment of its operational history and the planning of potential service activities after installation, such as checking the timing system, lubrication system, or verifying seals. This allows the engine to be consciously incorporated into a vehicle repair or upgrade project, while maintaining control over the further service cycle.

Benefits of choosing an original Audi engine

Choosing an original unit from the Audi family allows you to maintain the consistency of the entire drivetrain – from the engine control unit and wiring harness to the exhaust and transmission systems. The factory V8 FSI construction minimizes the risk of compatibility issues with accompanying components, which is particularly important in the case of such a high-performance unit as the one used in the RS4 B7.

The "bare" engine is a good starting point for both standard replacement and more advanced projects where, for example, upgrades to accessories, intake, or exhaust systems are planned. Retaining the original engine code also facilitates later computer diagnostics and the use of Audi service documentation.

Condition, origin, and purpose

The unit is offered as a used engine, which means it comes from vehicle dismantling and has undergone real-world road use. This type of solution is often chosen as an economical alternative to a full overhaul or purchasing a new short block, while maintaining the manufacturer's original specifications. The engine is intended for informed users and workshops that plan professional installation and potential service activities before starting it in the target vehicle.

Thanks to maintaining compliance with Audi's factory assumptions, the unit fits well into renovation projects, post-collision rebuilding, or replacement after mechanical failure. Engines of this type are particularly sought after by RS model enthusiasts who want to maintain the original drivetrain configuration without interfering with the body structure or electrical installation.

Installation recommendations and additional information

Before installation, it is recommended to carry out a standard package of preparatory activities, such as checking for leaks, verifying the condition of internal components, and replacing consumables in accordance with Audi service procedures. Professional installation in a specialized workshop will allow you to fully utilize the potential of the BNS 4.2 FSI unit and reduce the risk of improper operation after startup.

If you are planning a comprehensive repair or upgrade of the engine area in your Audi and need other components from the same group, such as blocks, heads, or complete short blocks, check out the available parts in the Audi Engines category.

For a comparison of the characteristics of different powertrains and a better understanding of potential operating costs, it is worth reading our guide: BMW E90 problematic engines: check what can ruin your budget!. This will allow you to better assess how important it is to choose the right unit and proper service maintenance in high-performance cars.