FJ Motorwerkes Rear Differential Bolt Collar Upgrade Kit – BMW X3M / X4M

Improve the precision, response and consistency of your BMW with the FJ Motorwerkes Rear Differential Bolt Collar Upgrade Kit.

This collar kit is designed to reinforce and stabilise the rear differential mounting arrangement in high-performance X3M and X4M applications. Designed for BMW F97 X3M and F98 X4M, this upgrade is suitable for performance road cars, track-focused builds and vehicles where more consistent suspension behaviour is required.

Key features

• Helps reduce unwanted movement around the differential mounting bolt
• Supports more consistent driveline behaviour under high torque
• Suitable for tuned, drag-raced and track-driven vehicles
• Purpose-built upgrade for F97 X3M and F98 X4M platforms

Installation

The differential mounting area should be inspected before installation. Professional workshop fitting and use of the correct torque procedure are strongly recommended.

Fitment note: Confirm exact kit contents, supported model years, supplied bolt compatibility and installation torque specifications before publishing.

Boost & Tune Bavarian can supply and professionally install this component in-house. A wheel alignment or suspension setup may be required after installation.

Supplier

FJ Motorwerkes

Product System

• Suspension & Brakes
• Transmission & Driveline

Vehicle Fitment

• BMW X3 M F97 chassis
• BMW X3 M F97 S58
• BMW X4 M F98 chassis
• BMW X4 M F98 S58

Confirm chassis, engine, drivetrain and production-year compatibility before ordering.

Supplier Part Number

FJM-F97-F98-DIFF-COLLAR

Built by Boost & Tune Support

BBT can assist with fitment review, installation, supporting modifications, configuration and calibration requirements where applicable.