Single Mass Flywheel for BMW Z4 M Roadster S54 (2003-2008)

Adapt an N54 or N55 GS6-53BZ transmission to your M5x/S5x engine to unlock superior torque capacity and optimized gear ratios.

Engineered for the BMW enthusiast who demands more strength and better gear ratios, the Turner Motorsport Transmission Swap Flywheel Kit provides a direct solution for mating a modern N54 or N55 6-speed gearbox to your M20, M5X, or S5X engine. This kit bridges the gap between generations, allowing you to run a high-capacity GS6-53BZ transmission without the typical fabrication nightmares.

The technical core of this kit is our dual-geometry flywheel. By utilizing this specialized design, you can retain your engine-side stock starter while using the factory clutch and throw-out bearing from your donor transmission. This ensures a precise fit and a firm, factory-like shifting feel that can handle significantly more power than older 5-speed setups. To guarantee a fitment, we’ve included a precision drill guide for bellhousing alignment and a universal pilot bearing pin to simplify the installation process.

Features and benefits:

Compatible with the starter from your original motor.
Uses factory clutch and throwout bearing from the donor transmission (GS6-53BZ).
Comes with necessary tools and a provided drill guide to adapt the top transmission mounting holes.
Kit contents:

Swap Flywheel
Pilot bearing input adapter for late N54 and N55 GS6
Drill guide, bit, and hardware.
Flywheel bolts
Optional pilot bearing
Optional clutch
Swap notes:

Fits M20/M50/M52/S50/S52/S54 engines
Needs a custom driveshaft and rear transmission mount. (We used https://www.hdtautoparts.com/driveshafts)
For E46 only: Rear transmission mount can be used from E46 330 6 Speed. Part numbers (22316760531 & 22316760532)
Installation and Support:

Click HERE for installation instructions:

BMW E46 E39 Z3 Z4 Lightweight Steel Flywheel is an exceptional performance upgrade designed to enhance your driving experience by providing quicker revs and reducing turbo lag. Engineered by Turner Motorsport, this flywheel is constructed from high-quality 6061-T6 billet aluminum with a high-carbon steel replaceable friction surface, ensuring durability and improved acceleration.

• Increased Acceleration: Reduced mass results in quicker engine revs and enhanced acceleration.
• High-Quality Materials: Made from 6061-T6 aircraft-grade billet aluminum for exceptional strength and performance.
• Durable Construction: Features a high-carbon steel replaceable friction surface and an OE steel ring gear secured by bolts.
• Lifetime Warranty: Comes with a limited lifetime warranty, underscoring its reliability and long-term performance.
• SFI Certification: Meets SFI Spec 1.1 or 1.2 standards, ensuring high-quality construction and safety.

This lightweight flywheel fits the following BMW models:

• 1999-2002 E46 BMW 323i, 323ci, 325i, 325ci, 328i, 328ci, 330i, 330ci (with 5-speed manual transmission)
• 2001-2005 E46 BMW 325xi, 330xi
• 1997-2002 Z3 BMW Z3 2.3, Z3 2.5i, Z3 2.8, Z3 3.0i