JB Racing BMW Drivetrain Parts for BMW Z Series E85/6 (2003-2008)

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Building your perfect BMW is more than just adding horsepower and stiff suspension. Your drivetrain needs attention in order to deliver power effectively. Most BMWs feature comfortable clutch discs, heavy flywheels, long shifter throws, and open differentials. The drivetrain transmits power to the wheels, but can also be a source of power loss when it is designed for comfort rather than performance. Everything on this page will help you improve your power delivery and driving experience by providing custom Limited Slip Differentials, Short Shift Conversions, Performance Clutch Discs, Lightweight Flywheels, and anything else your BMW needs to be the perfect driving experience.

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E60, E82, E85, E9X, E89 (N52 Engine) JB Racing Lightweight Aluminum Flywheel
E60, E82, E85, E9X, E89 (N52 Engine) JB Racing Lightweight Aluminum F...
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T#:2801
Part#: 520-200-240
Ships in 6 Business Days
$ 714.00 USD
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Aluminum flywheels are much lighter than the stock steel flywheel and that produces better throttle response and more available horsepower to the wheels for faster acceleration. The JB Racing aluminum flywheels are a direct replacement for the stock flywheel and work with stock clutch components for an easy upgrade with very little downside.

Modern flywheels are built with additional components and features that are designed to dampen and minimize vibrations from the engine and transmission. As a result they have become bloated in weight and that means more energy is used up just making the flywheel spin. The weight difference between an aluminum and steel flywheel is huge - sometimes more than 50% less. Without the additional mass, more energy can be diverted to where it counts most - moving the car. The flywheel and clutch is one of the first areas that engine builders address when making the rotating assembly lighter for race engines. The dampening effect is just not needed on cars that are focused on performance.

In addition to releasing more power to the wheels, the lighter flywheel allows the engine to spin more freely, which improves throttle response. Again, the difference is huge as you watch the revs build faster than before. With the engine spinning easier the power band comes up much sooner. The stock steel flywheel feels lazy in comparison. There is a driving adjustment required to get used to how much faster the engine revs but that's not really a downside.

The JB lightweight flywheel is designed to be used with a factory organic clutch - the same clutch kit that you would get from any BMW dealer. This makes replacement clutch components easy to source and inexpensive when compared to specialized racing clutches. By using the factory BMW clutch, JB has also made the whole assembly easy to live with when used on the street. The clutch behaves the same as it originally did - just with better throttle response and more power! The JB flywheel can also be rebuilt with a new clutch contact surface - you don't have to buy a new flywheel.

Aluminum flywheels are considered 'single-mass' flywheels because they do not have the same dampening designs as an original 'dual-mass' flywheel. With a single-mass design more noise and vibration may be noticeable. There are steps you can take to minimize the noise - heavier weight transmission oil and clutch discs with anti-rattle springs (sprung-hub clutch).

This JB flywheel replaces the stock flywheel and can be used with either the stock 228mm or stock 240mm clutch discs. Depending on the model you may have either clutch size in your car but this flywheel is compatible with both. You can install a 240mm clutch as a mild upgrade.

Stock Flywheel Weight = 24-31.0lbs
JB Flywheel Weight = 12.0lbs

This item fits the following BMWs:
2006-2010 E60 BMW - 525i, 528i, 530i
2006-2013 E90, E91, E92, E93 BMW - 325i, 328i, 330i
2007-2013 E82 BMW - 125i, 128i
2006-2008 E85, E86 BMW - Z4 3.0i, Z4 3.0si
2009-later E89 BMW - Z4 3.0i
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Z4 M HD Clutch and Flywheel Kit
Z4 M HD Clutch and Flywheel Kit
JB Racing - Corporate Logo
T#:878
Part#: 520-010S-S873G
Ships on Jul 29, 2025
$ 1,488.61 USD
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This lightweight aluminum flywheel w/ Heavy Duty "sprung-hub" clutch package is the best-engineered solution for E46 325 and 330 models with the 6-speed transmission, Z4 2.5/3.0, and Z4 M Roadster and M Coupe. Instead of picking a clutch from another car that may or may not work at all, the engineers at JB Racing have taken all of the guess work out of this upgrade and incorporated a Sachs sport sprung-hub clutch with the correct pressure plate and combined it with their most-popular aluminum lightweight flywheel. The Sachs HD clutch disc has a sprung hub to minimize noise and vibration and organic linings to give the feel and engagement of a stock clutch. Mixing and matching of the incorrect clutch, pressure plate, and flywheel components can lead to inconsistent engagement and feel -- why make your clutch feel worse?

In addition, the Sachs HD pressure plate will clamp with greater force -- allowing approximately 350 ft-lbs of torque, which makes it an obvious upgrade from the stock clutch kit. And with the aluminum flywheel weight savings is substantial over the stock dual-mass flywheel - which allows your motor to spool up faster and transmit more HP to the ground.

Because Sachs is an OE supplier to most German cars, replacement parts are just a phone call away. This kit uses the stock throw-out bearing (included in the price).

Z4 M Sport Clutch and Flywheel Applications:
2006-2008 E85 Z4, E86 Z4 Z4 M Roadster, Z4 M Coupe
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JB Racing Single Mass Lightweight Aluminum Flywheel - 6-speed - E46 325i/330i, E60 525/530i, E83 X3, Z4 3.0i
JB Racing Single Mass Lightweight Aluminum Flywheel - 6-speed - E46 3...
JB Racing - Corporate Logo
T#:3474
Part#: 520-190-240
Ships in 5 Business Days
$ 672.00 USD
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$ 672.00 USD
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This is a performance replacement for BMW Part # 21207533868 Aluminum flywheels are much lighter than the stock steel flywheel and that produces better throttle response and more available horsepower to the wheels for faster acceleration. The JB Racing aluminum flywheels are a direct replacement for the stock flywheel and work with stock clutch components for an easy upgrade with very little downside.

Modern flywheels are built with additional components and features that are designed to dampen and minimize vibrations from the engine and transmission. As a result they have become bloated in weight and that means more energy is used up just making the flywheel spin. The weight difference between an aluminum and steel flywheel is huge - sometimes more than 50% less. Without the additional mass, more energy can be diverted to where it counts most - moving the car. The flywheel and clutch is one of the first areas that engine builders address when making the rotating assembly lighter for race engines. The dampening effect is just not needed on cars that are focused on performance.

In addition to releasing more power to the wheels, the lighter flywheel allows the engine to spin more freely, which improves throttle response. Again, the difference is huge as you watch the revs build faster than before. With the engine spinning easier the power band comes up much sooner. The stock steel flywheel feels lazy in comparison. There is a driving adjustment required to get used to how much faster the engine revs but that's not really a downside.

The JB lightweight flywheel is designed to be used with a factory organic clutch - the same clutch kit that you would get from any BMW dealer. This makes replacement clutch components easy to source and inexpensive when compared to specialized racing clutches. By using the factory BMW clutch, JB has also made the whole assembly easy to live with when used on the street. The clutch behaves the same as it originally did - just with better throttle response and more power! The JB flywheel can also be rebuilt with a new clutch contact surface - you don't have to buy a new flywheel.

Aluminum flywheels are considered 'single-mass' flywheels because they do not have the same dampening designs as an original 'dual-mass' flywheel. With a single-mass design more noise and vibration may be noticeable. There are steps you can take to minimize the noise - heavier weight transmission oil and clutch discs with anti-rattle springs (sprung-hub clutch).

The JB Flywheel includes the pilot bearing mounted in the flywheel hub, just like the factory configuration.

Stock Flywheel Weight = 25.0lbs
JB Flywheel Weight = 10.5lbs

This item fits the following BMWs:
2002-2005 E46 BMW 325i 330i (with 6-speed manual transmission)
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JB Racing Lightweight Steel Flywheel - Grand-Am Legal - E46, MZ3, Z4
JB Racing Lightweight Steel Flywheel - Grand-Am Legal - E46, MZ3, Z4 ...
JB Racing - Corporate Logo
T#:40748575
Part#: 520010240SGA
Ships Jul 21, 2025
New Item
$ 868.00 USD
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$ 868.00 USD
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This lightened steel flywheel is specifically designed (and approved) for use in Grand-Am road racing but can also be used as a mild street upgrade if a full aluminum lightweight flywheel is not called for. The Grand-Am flywheel is 20% lighter than stock to meet the rules for the GS and ST classes.Modern flywheels are built with additional components and features that are designed to dampen and minimize vibrations from the engine and transmission. As a result they have become bloated in weight and that means more energy is used up just making the flywheel spin. A lightweight flywheel does away with the dual mass design and its additional mass so more energy can be diverted to where it counts most - moving the car. The flywheel and clutch is one of the first areas that engine builders address when making the rotating assembly lighter for race engines. The dampening effect is just not needed on cars that are focused on performance.

In addition to releasing more power to the wheels, the lighter flywheel allows the engine to spin more freely, which improves throttle response. The engine revs much faster than before. With the engine spinning easier the power band comes up much sooner. The stock steel flywheel feels lazy in comparison. There is a driving adjustment required to get used to how much faster the engine revs but that's not really a downside.

Grand-Am approved this flywheel to be used with a factory E36 M3 clutch. This opens up a lot of clutch and pressure plate options but we typically used this with a stock Sachs OEM clutch kit. This makes replacement clutch components easy to source and inexpensive when compared to specialized racing clutches.

Lightweight flywheels are considered 'single-mass' flywheels because they do not have the same dampening designs as an original 'dual-mass' flywheel. With a single-mass design more noise and vibration may be noticeable. There are steps you can take to minimize the noise - heavier weight transmission oil and clutch discs with anti-rattle springs (sprung-hub clutch). In addition to the standard replacement clutches, we also sell Sachs Performance sprung hub clutches that also work with the JB flywheels.

If being used on a 330i 6-speed or Z4 6-speed an additional pilot bearing hub is required. Select your appropriate model and transmission from the list below.

Stock Flywheel Weight = 25.0lbs
JB Flywheel Weight = 20.0lbs

This item fits the following BMWs:
2001-2002 E46 BMW 330i 330ci 5-speed
2003-2006 E46 BMW 330i 330ci 6-speed
2001-2006 E46 BMW M3
1998-2002 Z3 BMW Z3 M Roadster M Coupe
2003-2005 E85 BMW Z4 2.5i Z4 3.0i
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