E36, E46, Z3, Z4 JB Racing Midweight Steel Flywheel

Want the benefits of a lightweight flywheel but are put off by all the talk of 'flywheel rattle'? This machined steel flywheel slots in between a heavy original dual mass steel and the lightweight aluminum flywheels. It weighs in at 15.5lbs - providing better throttle response and power gains without losing factory-type refinement.

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. There is a driving adjustment required to get used to how much faster the engine revs but that's not really a downside.

JB Racing has engineered this flywheel to accept the E36 M3's 240mm 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. The Sachs sprung hub clutch kit can also work for greater torque capacity and silent operation.

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 but since this flywheel is not as 'radical' as our other lightweight designs the gear rattle and other noises should be kept to a minimum. 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.

Stock Flywheel Weight = 25.0lbs
JB Flywheel Weight = 15.5lbs

This item fits the following BMWs:
1992-1999 E36 BMW 323is 323ic 325i 325is 325ic 328i 328is 328ic M3
1999-2002 E46 BMW 323i 323ci 325i 325ci 328i 328ci 330i 330ci (5-speed)
1997-2002 Z3 BMW Z3 2.3 Z3 2.5i Z3 2.8 Z3 3.0i M Roadster M Coupe
2003-2005 E85 BMW Z4 2.5i Z4 3.0i (5-speed)
T#: 182519 | Part#: 520-010-240S
868.00 $868.00
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Direct Ship, Expected Ship Date: Aug 10, 2021
E36, E46, Z3, Z4 JB Racing Midweight Steel Flywheel